![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/08\/image.png\")
<\/figure><\/div>\n\n\n5. concept of biological properties of soil<\/h3>\n\n\n\n
\u3000By the way, when I present the above four conditions, I am often asked why they do not include conditions on the biological properties of the soil (from microbes to animals). Why is it that these four conditions do not include the biological properties of the soil (from microorganisms to animals)? It is not easy to fully explain why in the limited space of a paper. However, we can at least point out the following
\u3000All of the above four conditions for good soil have a significant impact on the life of organisms in the soil. However, we do not believe that the fulfillment of these four conditions has a negative impact on the life of organisms in the soil. For this reason, we have not added the biological condition of the soil to the conditions for good soil.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c\uff12\u56de\u3000\u3088\u3044\u571f\u306e\u6761\u4ef6\u3000\u7269\u7406\u7684\u6027\u8cea\u2212\u305d\u306e\uff11
\u6839\u3092\u652f\u3048\u308b\u571f\u306e\u539a\u307f<\/h2>\n\n\n\n
\u4ee4\u548c\uff13 (2021) \u5e74\u3000\uff16\u6708\u53f7 (\u7b2c731\u53f7)<\/p>\n\n\n\n
\u3000In last month's issue, we presented four conditions and their target values for good soil for crop production. From this month onward, each of the four conditions will be explained. In this issue, we will focus on the first condition, \"soil thickness and hardness,\" which is one of the conditions related to the physical properties of soil, and consider its thickness.<\/p>\n\n\n\n
First, let's dig up the soil.<\/h3>\n\n\n\n
\u3000In last month's issue, I mentioned that a veteran chef at a famous hotel in Sapporo remarked that he could harvest many delicious potatoes just by looking at the soil. However, I do not have the courage to say such a thing. I don't know what is inside the soil where the roots of the crops grow, even if I stand in the field where the crops are cultivated (the same is true in a home garden) and look at the soil from above. You cannot know what is inside the soil unless you dig it up. First of all, I would like you to choose an area where the crop growth is average in the field and dig the soil by yourself with a shovel.
\u3000\u6398\u308b\u6df1\u3055\u306f1m\u304c\u76ee\u5b89\u3002\u592a\u967d\u3092\u80cc\u4e2d\u306b\u53d7\u3051\u308b\u3088\u3046\u306b\u3057\u3066\u6398\u308b\uff08\u56f3\uff11) \u3002\u305f\u3060\u306a\u3093\u3068\u306a\u304f\u6398\u308b\u306e\u3067\u306f\u306a\u304f\uff0c\u81ea\u5206\u306b\u5bfe\u3057\u3066\u6b63\u9762\u3068\u306a\u3063\u305f\u3068\u3053\u308d\u306f\uff0c\u571f\u306e\u8868\u9762\u304b\u3089\u5782\u76f4\u306b\u58c1\u72b6\u306b\u3059\u308b\u3053\u3068\u306b\u6c17\u3092\u3064\u3051\u308b\u3002<\/p>\n\n\n\n![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/08\/image-1.png\")
<\/figure>\n\n\n\n\u3053\u306e\u58c1\u72b6\u3068\u306a\u3063\u305f\u3068\u3053\u308d\u3092\u571f\u306e\u300c\u65ad\u9762\u300d\u3068\u3044\u3046\u3002
\u3000When you are digging with a shovel, I want you to remember the hardness of the soil and the feel of the shovel. The reason is that whether you can dig soil easily or not is related to the condition of \"soil hardness,\" which will be discussed in the next article. If the soil becomes too hard to dig, or if it becomes too hard to dig because of rocks (Figure 2), the digging will be terminated.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/08\/image-2.png\")
<\/figure><\/div>\n\n\n2. soil has two different thicknesses<\/h3>\n\n\n\n
\u3000If you look at a cross section of soil, you will notice that there is a layer of black soil at the top of the cross section and a layer below that in which the black color has disappeared (Figure 3). This black layer of soil is called the surface soil (or crop soil). The layer of soil below this layer is the subsoil (or heartsoil). For the sake of convenience, we will consider the subsoil to be the area from the boundary with the surface soil to the point where it cannot be dug with a shovel.
\u3000There are two types of soil thicknesses that are one of the conditions for good soil for crop production. One is the thickness of the surface soil. The other is the thickness that allows roots to grow comfortably in the soil. This range of thickness is called the effective soil layer (Figure 3).
\u3000To be a good soil for crop production, the thickness of the surface soil should be about 20 to 30 cm, and the effective soil layer should be at least 50 cm thick. For example, in the cross section of soil shown in Figure 3, the thickness of the surface soil is about 20 cm. The thickness of the subsoil from the boundary to the point where it is too hard to dig is about 30 cm, so when combined with the thickness of the surface soil, the effective soil layer is about 50 cm. Therefore, it can be judged that the soil in Figure 3 just barely meets the two thickness requirements for good soil.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/08\/image-3.png\")
<\/figure><\/div>\n\n\n3. surface soil thickness is closely related to tillage operations<\/h3>\n\n\n\n
\u3000\u8868\u5c64\u571f\u306f\u571f\u306e\u65ad\u9762\u306e\u6700\u4e0a\u90e8\u306b\u3042\u3063\u3066\u9ed2\u8272\u3092\u5448\u3057\u3066\u3044\u308b\u3002\u8015\u5730\u3067\u306f\u683d\u57f9\u304c\u7d42\u308f\u3063\u305f\u5f8c\u306e\u53ce\u7a6b\u6b8b\u6e23\u3084\uff0c\u571f\u306e\u4e2d\u306b\u6b8b\u3055\u308c\u305f\u4f5c\u7269\u306e\u6839\uff0c\u3055\u3089\u306b\u306f\u5806\u80a5\u306a\u3069\u3082\u542b\u3081\u3066\u69d8\u3005\u306a\u6709\u6a5f\u7269\u304c\u571f\u306e\u8868\u9762\u306b\u6dfb\u52a0\u3055\u308c\u308b\u3002\u305d\u308c\u3089\u306f\u30d7\u30e9\u30a6\u8015\u3067\u571f\u306b\u3059\u304d\u8fbc\u307e\u308c\uff0c\u30ed\u30fc\u30bf\u30ea\u8015\u3067\u571f\u3068\u6df7\u548c\u3055\u308c\u308b\u3002\u571f\u3068\u6df7\u548c\u3055\u308c\u305f\u6709\u6a5f\u7269\u306f\u571f\u306e\u4e2d\u306e\u5fae\u751f\u7269\u306b\u3088\u3063\u3066\u5f90\u3005\u306b\u5206\u89e3\u3055\u308c\u3066\u3044\u304f\u3002\u5fae\u751f\u7269\u306b\u3088\u3063\u3066\u5206\u89e3\u3055\u308c\u306b\u304f\u3044\u90e8\u5206\u304c\u571f\u306b\u6b8b\u3063\u3066\u571f\u306e\u6709\u6a5f\u7269\uff08\u8150\u690d\uff09\u306b\u306a\u308b\u3002\u571f\u306e\u6709\u6a5f\u7269\uff08\u8150\u690d)\u306f\u9ed2\u8272\u306e\u8907\u96d1\u306a\u6709\u6a5f\u5316\u5408\u7269\u3067\u3042\u308b\u305f\u3081\uff0c\u305d\u308c\u304c\u8868\u5c64\u571f\u306e\u8272\u306b\u9ed2\u3055\u3092\u4e0e\u3048\u308b\u3002
\u3000As the added organic matter is repeatedly incorporated and mixed deeper into the soil, the thickness of the surface soil gradually increases. Thus, the surface soil is affected by human influence. Therefore, if the thickness of the surface soil does not reach 20 cm, which is the lower limit of the target value, it can be increased by actively feeding organic matter such as compost.
\u3000This topsoil is sometimes referred to as crop soil in agricultural terms. However, the thickness of the two is not always the same. The crop layer is the layer of soil within the area where the soil is plowed inverted by the plow. The depth at which the soil is plowed is the thickness of the crop layer.
\u3000The surface soil provides a place for crop roots to establish and absorb nutrients. In other words, this is the soil layer that has the greatest influence on crop growth. Human activities on the soil for crop production are also basically directed to the surface soil. The management of the surface soil is an important factor in determining the crop productivity of a field.<\/p>\n\n\n\n
4. soil thickness that allows roots to grow<\/h3>\n\n\n\n
\u3000\u6839\u304c\u4f38\u3073\u3066\u3044\u304f\u3053\u3068\u304c\u3067\u304d\u308b\u571f\u306e\u539a\u307f\uff0c\u3059\u306a\u308f\u3061\uff0c\u6709\u52b9\u571f\u5c64\u306e\u539a\u307f\u3092\u55b6\u8fb2\u4f5c\u696d\u3067\u5897\u3084\u3059\u3068\u3044\u3046\u306e\u306f\u4e8b\u5b9f\u4e0a\u4e0d\u53ef\u80fd\u3067\u3042\u308b\u3002\u8868\u5c64\u571f\u306b\u5bfe\u3057\u3066\u306a\u3089\uff0c\u3059\u3067\u306b\u8ff0\u3079\u305f\u3088\u3046\u306b\u4eba\u70ba\u7684\u306a\u6539\u5584\u304c\u53ef\u80fd\u3067\u3042\u308b\u3002\u3057\u304b\u3057\uff0c\u305d\u306e\u4e0b\u306e\u4e0b\u5c64\u571f\u306f\u571f\u6728\u5de5\u4e8b\u3067\u3082\u3057\u306a\u3044\u9650\u308a\uff0c\u4eba\u306e\u64cd\u4f5c\u3067\u539a\u307f\u3092\u6539\u5909\u3059\u308b\u3053\u3068\u306f\u3067\u304d\u306a\u3044\u3002\u6709\u52b9\u571f\u5c64\u3092\u6c7a\u3081\u308b\u5927\u304d\u306a\u8981\u56e0\u306f\uff0c\u6839\u304c\u901a\u904e\u3067\u304d\u306a\u3044\u77f3\u3053\u308d\uff08\u30ec\u30ad\uff1d\u792b\uff09\u306e\u5c64\u3084\u5ca9\u76e4\uff0c\u3055\u3089\u306b\u3061\u5bc6\u3067\u786c\u3044\u571f\u5c64\u306a\u3069\u3067\u3042\u308b\u3002\u3053\u3046\u3057\u305f\u5c64\u306f\u571f\u6728\u5de5\u4e8b\u3067\u9664\u53bb\u3057\u306a\u3044\u304b\u304e\u308a\u79fb\u52d5\u3057\u3066\u3044\u304b\u306a\u3044\u3002\u3053\u306e\u305f\u3081\uff0c\u79c1\u305f\u3061\u304c\u55b6\u8fb2\u4f5c\u696d\u306a\u3069\u3067\u6539\u5584\u3067\u304d\u308b\u3082\u306e\u3067\u306f\u306a\u3044\u3002
\u3000Figure 2 shows an example where a large amount of leki is present at about 50 cm from the soil surface, which limits the thickness of the effective soil layer. It is possible to use a machine to determine whether or not there is any rubble in the subsoil layer. However, such exploration is not common. Also, the presence of the hard, difficult-to-excavate soil layer shown in Figure 3 in the soil can basically only be determined by digging.
\u3000The effective soil layer is the soil layer within which the crop roots can spread. If the effective soil layer is too thin, not only will it not be able to adequately support the crop, but it will also limit the area where nutrient water can be absorbed. If the effective soil layer is restricted to a thickness of less than 50 cm, crop growth is inhibited. However, it is quite difficult to artificially increase its thickness.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c\uff13\u56de \u3088\u3044\u571f\u306e\u6761\u4ef6 \u7269\u7406\u7684\u6027\u8cea\u2212\u305d\u306e\uff12
\u571f\u306e\u786c\u3055\u306f\u3069\u306e\u3088\u3046\u306b\u3057\u3066\u304d\u307e\u308b\u306e\u304b<\/h2>\n\n\n\n
\u4ee4\u548c\uff13 (2021) \u5e74\u3000\uff17\u6708\u53f7 (\u7b2c732\u53f7)<\/p>\n\n\n\n
\u3000Last month, we discussed soil thickness in terms of \"soil thickness and hardness,\" one of the four conditions for good soil for crop production, which is related to the physical properties of soil. This month, we will focus on soil hardness.<\/p>\n\n\n\n
1. what determines soil hardness<\/h3>\n\n\n\n
\u3000\u571f\u306b\u306f\u30b9\u30b3\u30c3\u30d7\u3067\u6398\u308b\u3053\u3068\u304c\u3067\u304d\u306a\u3044\u304f\u3089\u3044\u786c\u3044\u571f\u3082\u3042\u308c\u3070\uff0c\u697d\u3005\u3068\u6398\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u571f\u3082\u3042\u308b\u3002\u3044\u3063\u305f\u3044\uff0c\u571f\u306e\u786c\u3055\u306f\u4f55\u306b\u3088\u3063\u3066\u6c7a\u307e\u308b\u306e\u304b\u3002\u57fa\u672c\u7684\u306b\u306f\u300c\u571f\u306e\u7c92\u300d\u306e\u5927\u304d\u3055\uff08\u7c92\u5f84\u3068\u3044\u3046\uff09\u304c\u571f\u306e\u786c\u3055\u3092\u6c7a\u3081\u3066\u3044\u308b\u3002\u571f\u306e\u7c92\uff1f\u3068\u4e0d\u601d\u8b70\u306b\u601d\u3046\u4eba\u304c\u3044\u308b\u304b\u3082\u3057\u308c\u306a\u3044\u3002\u3057\u304b\u3057\uff0c\u7802\u3068\u7c98\u571f\u3092\u601d\u3044\u51fa\u3057\u3066\u307b\u3057\u3044\u3002\u7802\u306f\u30b6\u30e9\u30b6\u30e9\u3057\u3066\u76ee\u3067\u898b\u3066\u4e00\u7c92\u4e00\u7c92\u3092\u78ba\u8a8d\u3067\u304d\u308b\u3002\u3057\u304b\u3057\u7c98\u571f\u306e\u7c92\u306f\uff0c\u76ee\u3067\u898b\u3066\u5927\u304d\u3055\u3092\u78ba\u8a8d\u3067\u304d\u305a\uff0c\u304b\u305f\u307e\u308a\u3067\u3057\u304b\u898b\u3089\u308c\u306a\u3044\u3002
\u3000When the organic matter contained in the soil is completely removed and only the soil particles are left, the soil is composed of three types of particles: sand (classified into two types: coarse sand and fine sand), clay (clay here does not refer to clay used for clay works but to the very fine soil particles shown in Figure 1), and silt (fine sand), which is intermediate in size between the two. The problem is how much proportion these three types of particles have. The question is what proportion of these three types of particles make up the soil.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image.png\")
<\/figure><\/div>\n\n\n2. the finer the soil grains, the harder the soil.<\/h3>\n\n\n\n
\u3000If a glass bead is packed in a certain container, the smaller the bead is, the more space it has. If the glass beads are large, they cannot be packed without gaps, and many spaces are created. The term \"denseness\" is used to describe how many particles are packed in a certain volume. The degree of density becomes larger when it is packed with a small glass ball than when it is packed with a large glass ball. Clay has the finest grains, so clayey soil has a high degree of density. On the other hand, sand has coarse grains, so sandy soil has a small degree of density. Therefore, clayey soil is tightly packed into a certain volume and becomes hard soil. Sandy soil with coarse particles does not often produce soil as hard as clayey soil.<\/p>\n\n\n\n
3. how is soil grain size determined?<\/h3>\n\n\n\n
\u3000Then, how is the size of soil grains determined? If soil grain size is innately determined, there would be no difference between sticky soil and sandy soil. Soil grain size is related to the way soil is formed.
\u3000The raw material of soil is basically rock (parent rock) (with the exception of black earth, which is derived from volcanic ash). The rock is broken into small pieces by weathering. The finely crushed rock is called the parent material of soil. The size of the particles that make up the soil is determined by the quality of the rocks used as raw material and the degree of weathering. If the soil has been exposed to weathering for a long time or if the rock is brittle and susceptible to weathering, the soil will have more fine particles, such as clay and silt. This results in fine-grained soil. The opposite is sandy (coarse-grained) soil. The intermediate state between the two is medium-grained soil.<\/p>\n\n\n\n
4. very long time is needed to change the hardness of the soil<\/h3>\n\n\n\n
\u3000The hardness of soil is due to the finer and denser particles of soil. The soil particles contain the time it took for the rocks to break up and for the soil to be formed by the action of living organisms. Thus, it takes a daunting, very long-term effort to essentially soften the hardness of the soil.
\u3000For example, by feeding coarse organic matter, such as compost, to the soil over many generations, a cushion of organic matter is created in the soil, which gradually softens the soil. In addition, one might think that mixing in sand or other materials would be a good idea. Of course, this is theoretically possible. It may be possible in a small area such as a home garden. However, in a large field, sand must be nearby in large quantities. Sand from the coast is not suitable because of its salinity. It must be river sand. Considering these factors, bringing sand into a fine-grained soil is a picture-perfect and unrealistic idea. It is impossible to change clayey soil into sandy soil.<\/p>\n\n\n\n
5. soil hardness is not determined by soil particles alone<\/h3>\n\n\n\n
\u3000So far, for the sake of simplicity, I have explained soil hardness only in terms of soil particles. However, soil hardness is not that simple. For example, soil hardness varies depending on the moisture content in the same soil. This can be seen from the fact that clay soil becomes hard and hard when it is dried. If such soil is gradually moistened with water, it becomes softer and softer, and finally liquefies into a sludge, which is outside the concept of hardness.
\u3000The nature of soil hardness is very complex, even when we speak of soil hardness in a nutshell. Here we are simplifying the story.<\/p>\n\n\n\n
6. hardness is not the only thing that affects root elongation<\/h3>\n\n\n\n
\u3000Last month and this month we discussed the issue of soil thickness and hardness. This is because we wanted to consider the thickness of the effective soil layer in which roots can grow. However, whether the roots can grow or not is not only determined by the hardness of the soil. There are three factors that inhibit the growth of crop roots. (1) mechanical resistance derived from soil hardness, (2) soil aeration, which indicates whether sufficient air is being pumped into the soil so that root respiration is not adversely affected, and (3) soil moisture conditions. These factors are not independent of each other, but are interrelated, making them even more complex.<\/p>\n\n\n\n
7. Hardness is not an inhibiting factor in general soil<\/h3>\n\n\n\n
\u3000Figure 2 shows the results of an experiment examining the relationship between the above three factors and root elongation. The volumetric weight of 1.0 in Figure 2 indicates that 1 cm3 contains 1 g of dry soil, which is a very normal value for ordinary soil. The increase in volumetric weight can be thought of as the soil particles becoming finer and more cohesive.
\u3000Therefore, according to Figure 2, when the soil is wet enough to form puddles, the gaps in the soil are filled with water and the soil lacks oxygen (poor aeration). Therefore, regardless of the volumetric weight of the soil, peas cannot fully extend their roots due to lack of oxygen.
\u3000When there is no puddle and the soil contains some water, mechanical resistance, i.e., soil stiffness, will now inhibit root growth. However, this is the case for slightly fine-grained (clayey) soil with a volume weight of more than 1.1. Ordinary soil with a volume weight of up to 1.0 has water and air in the spaces between the soil, so it is in optimum condition for root growth.
\u3000When the soil becomes dry, mechanical resistance due to hardness inhibits root elongation in soils with large volumetric weights (fine-grained and clayey). However, in a typical soil with a volume weight of 1.0, mechanical resistance due to hardness does not inhibit root elongation. And, of course, in a soil so dry that the crop wilts, lack of water inhibits root elongation regardless of the volume weight.
\u3000In other words, it is concluded that soil hardness is a problem in fine-grained soil (clayey soil), and that in general soil hardness itself should not be considered to be an impediment to root growth. For soils with low volumetric weight and light weight, such as black granite soil (soil derived from volcanic ash), soil hardness is hardly a problem. In fact, because of its lightness, black soil is susceptible to wind erosion (soil being blown away by the wind).<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-1.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c\uff14\u56de\u3000\u3088\u3044\u571f\u306e\u6761\u4ef6\u3000\u7269\u7406\u7684\u6027\u8cea\u2212\u305d\u306e\uff13
\u65ad\u9762\u3067\u308f\u304b\u308b\u6392\u6c34\u306e\u826f\u5426<\/h2>\n\n\n\n
\u4ee4\u548c\uff13 (2021) \u5e74 8\/9\u6708\u5408\u4f75\u53f7 (\u7b2c733\u53f7)<\/p>\n\n\n\n
\u3000In this issue, we will first consider how to judge whether the soil drains well or not, based on the second of the four conditions for good soil for crop production, which relates to the physical properties of the soil, namely, that it retains moisture reasonably well and drains well.<\/p>\n\n\n\n
1. observe the cross section of the soil closely<\/h3>\n\n\n\n
\u3000For example, if you have experienced a puddle of water in a field after a heavy rainfall, and the water remains there indefinitely, you should be able to feel that the soil has poor drainage properties. However, if you want to know more about how bad the drainage is, dig a hole in the soil to make a cross-section of the soil and observe it, as described in the second article of this series (June issue). You can determine whether the soil drains well or not by looking at the cross section of the soil as described below.
\u3000There is no special pattern in the cross-section of normal soil (Figure 1-a). The soil has a blackish topsoil followed by a brownish-brown subsoil with a fading black color. Soil with such a cross-section is considered to have good drainage.
\u3000However, you may find an iron rust (brownish-brown) pattern (this is called a mottled pattern) or, in some cases, a bluish-gray layer of soil (this is called a gully layer), as shown in Figure 1-b) on the cross section (Figure 1-c). When mottling is present, drainage is judged to be somewhat poor, and a gully layer indicates that drainage is so poor that groundwater stagnates.
\u3000Why is it possible to determine good drainage from mottled or blue-gray soil? It is due to the nature of iron, which is contained in large amounts in the soil (Figure 2).<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-2.jpg\")
<\/figure><\/div>\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-2.png\")
<\/figure><\/div>\n\n\n2. mottled cross section = soil with slightly poor drainage<\/h3>\n\n\n\n
\u3000\u7551\u306e\u571f\u306f\uff0c\u7a7a\u6c17\u304c\u571f\u306e\u3059\u304d\u9593\u306b\u306f\u3044\u308a\u8fbc\u3080\u306e\u3067\u9178\u7d20\u304c\u5b58\u5728\u3057\u3066\u3044\u308b\u3002\u3053\u306e\u3088\u3046\u306a\u72b6\u614b\u3092\u9178\u5316\u7684\u72b6\u614b\u3068\u3044\u3046\u3002\u9178\u5316\u7684\u72b6\u614b\u306b\u3042\u308b\u3068\uff0c\u571f\u306e\u9244\u306f\u6c34\u306b\u6eb6\u3051\u306a\u3044\u30b5\u30d3\u8272\u306e\u9244\u3068\u3057\u3066\u5b58\u5728\u3057\u3066\u3044\u308b\u3002\u3068\u3053\u308d\u304c\u571f\u306e\u6392\u6c34\u304c\u3084\u3084\u60aa\u3044\u3068\uff0c\u5927\u96e8\u304c\u964d\u3063\u305f\u3068\u304d\u306b\u96e8\u6c34\u304c\u571f\u306e\u4e2d\u3067\u6ede\u7559\u3057\uff0c\u7d50\u679c\u7684\u306b\u5730\u4e0b\u6c34\u4f4d\u304c\u4e0a\u304c\u3063\u3066\u304f\u308b\u3002\u3059\u308b\u3068\uff0c\u4e00\u6642\u7684\u306b\u571f\u306e\u3059\u304d\u9593\u304c\u6c34\u3067\u6e80\u305f\u3055\u308c\u3066\u9178\u7d20\u4e0d\u8db3\u306e\u72b6\u614b\u306b\u306a\u308b\u3002\u3053\u308c\u3092\u9084\u5143\u7684\u72b6\u614b\u3068\u3044\u3046\u3002\u9178\u5316\u7684\u306a\u6642\u306e\u9244\u306f\u30b5\u30d3\u8272\u3067\u6c34\u306b\u6eb6\u3051\u306a\u3044\u72b6\u614b\u306a\u306e\u3060\u304c\uff0c\u9084\u5143\u7684\u306a\u72b6\u614b\u306b\u306a\u308b\u3068\uff0c\u9244\u306f\u9752\u7070\u8272\u306e\u9244\u306b\u5909\u5316\u3057\u3066\u6c34\u306b\u6eb6\u3051\u51fa\u3059\u3002\u3057\u304b\u3057\uff0c\u305d\u306e\u5f8c\u518d\u3073\u4e7e\u71e5\u304c\u7d9a\u304f\u3068\uff0c\u6392\u6c34\u304c\u307e\u3063\u305f\u304f\u60aa\u3044\u308f\u3051\u3067\u306f\u306a\u3044\u306e\u3067\uff0c\u5c11\u3057\u305a\u3064\u571f\u306e\u4e2d\u306e\u6c34\u304c\u6392\u6c34\u3055\u308c\u3066\u3044\u304d\uff0c\u5730\u4e0b\u6c34\u4f4d\u304c\u4e0b\u304c\u3063\u3066\u571f\u306e\u3059\u304d\u9593\u306b\u7a7a\u6c17\u304c\u3082\u3069\u3063\u3066\u304d\u3066\u9178\u5316\u7684\u306b\u306a\u308b\u3002\u305d\u3046\u3059\u308b\u3068\uff0c\u9244\u306f\u518d\u3073\u6c34\u306b\u6eb6\u3051\u306a\u3044\u30b5\u30d3\u8272\u306e\u9244\u306b\u304b\u308f\u308b\u3002
\u3000As the groundwater rises and falls with each rainfall, and the soil repeatedly goes through oxidizing and reducing states, the iron that dissolves during the reducing state collects and clumps together. This is the rusty iron mottling. Since mottling is not produced unless the groundwater level rises and falls, the presence of mottling indicates that the groundwater rises and falls because the soil drainage is somewhat poor.<\/p>\n\n\n\n
3. blue-gray layer in cross section = poorly drained soil<\/h3>\n\n\n\n
\u3000On the other hand, if drainage is really poor, the groundwater table is relatively high because water is stagnant in the soil. Thus, the soil immersed in groundwater remains in a reduced state because the crevices are filled with water. As a result, iron continues to exist as blue-gray iron that is soluble in water, resulting in the formation of a blue-gray gley layer. Therefore, the presence of a gley layer means that groundwater is stagnant up to that point and that the soil drains very poorly.
\u3000\u3061\u306a\u307f\u306b\uff0c\u3053\u306e\u9752\u7070\u8272\u306e\u30b0\u30e9\u30a4\u5c64\u306e\u571f\u3092\u53d6\u308a\u51fa\u3057\u7a7a\u6c17\u306b\u89e6\u308c\u3055\u305b\u308b\u3068\uff0c\u7a7a\u6c17\u4e2d\u306e\u9178\u7d20\u306b\u3088\u3063\u3066\u5f90\u3005\u306b\u9178\u5316\u3055\u308c\uff0c\u30b5\u30d3\u8272\uff08\u8336\u8910\u8272\uff09\u306e\u6c34\u306b\u6eb6\u3051\u306a\u3044\u9244\u306e\u5f62\u614b\u306b\u5909\u5316\u3057\u3066\u3044\u304f\u3002\u571f\u306e\u8272\u306b\u4e0e\u3048\u308b\u9244\u306e\u9762\u767d\u3044\u6027\u8cea\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
4. method of improving soil with poor drainage<\/h3>\n\n\n\n
\u3000Now that we know whether drainage is good or bad, how can we improve soil with poor drainage? In a small-scale field such as a vegetable garden, there are methods such as making ditches to allow stagnant water on the ground surface to flow out, or raising the height of the cultivation area (ridges).
\u3000However, in a large area such as a farmer's field, civil engineering work is required to dig a drainage ditch (this ditch is called a culvert) or to bury a drainage pipe under the field (this is called a culvert) and connect it to a drainage ditch (Figure 3).<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-3.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c\uff15\u56de\u3000\u3088\u3044\u571f\u306e\u6761\u4ef6\u3000\u7269\u7406\u7684\u6027\u8cea\u2212\u305d\u306e\uff14
\u9069\u5ea6\u306b\u6c34\u3092\u4fdd\u6301\u3057\u6392\u6c34\u3082\u3088\u3044\u571f\u3068\u306f<\/h2>\n\n\n\n
\u4ee4\u548c\uff13 (2021) \u5e74\u300010\u6708\u53f7 (\u7b2c734\u53f7)<\/p>\n\n\n\n
\u3000The second of the four conditions for good soil, which concerns the physical properties of the soil, is that the soil should \"retain a moderate amount of moisture and have moderate drainage. In the previous article, I described how to determine whether the soil drains well or not from the cross-section of the soil. This time, we will consider how soil retains water, the fact that some water in the soil can be used by crops and some cannot, and what kind of soil retains water adequately and drains well.<\/p>\n\n\n\n
1. capillary tension is the key to water retention and drainage<\/h3>\n\n\n\n
\u3000See Figure 1. Two types of glass capillaries of different thicknesses are placed in water dyed with blue ink (hereinafter referred to as \"ink\"). In both glass capillaries, the surface of the water rises slightly. This is called capillary action, and the force that pulls up the water is capillary tension. The reason why the ink is raised higher in the thinner glass capillary is because the capillary tension is stronger than in the thicker glass capillary.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-4.png\")
<\/figure><\/div>\n\n\n\u3000When this glass capillary was lifted above the surface of the ink, the ink in the thin glass capillary remained in the capillary, while the ink in the thick capillary fell to the floor (Figure 2). The capillary tension in the thin glass capillary is stronger than that of gravity, and thus water is retained in the capillary. However, the capillary tension in the thick glass capillary is weaker than the downward pull of gravity, and as a result, the ink fell out of the capillary (drainage).<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-5.png\")
<\/figure><\/div>\n\n\n\u3000Let us consider this in terms of the gaps in the soil. The space between particles in soil is composed of small, thin gaps and large, thick gaps. Sandy soil with coarse grains (coarse-grained soil) has fewer small gaps and more large gaps, so the capillary tension in the gaps is weak and water tends to drain out. This results in poor water retention, which can lead to drought damage to crops. On the other hand, fine-grained and cohesive soil (fine-grained soil) has many small gaps and few large gaps, so the capillary tension in the gaps is strong. Therefore, water is retained in the narrow gaps, resulting in poor drainage.<\/p>\n\n\n\n
2. water that can and cannot be used by crops<\/h3>\n\n\n\n
\u3000Imagine that there has been a very heavy rainfall and that all the crevices in the soil have been filled with water. There is no space for air to enter the soil, and there are only soil particles and water. The amount of water in the soil at this time is called the \"maximum water capacity. However, about 24 hours after the rain stops, the water that was held in the thick crevices by a force weaker than gravity is pulled down by gravity and drains away. Air enters the gap where the water has been drained away. The amount of water in the soil at this time is called the \"field water capacity. Of course, the drained water cannot be absorbed and used by the crop.
\u3000\u3053\u306e\u72b6\u614b\u304b\u3089\u3057\u3070\u3089\u304f\u96e8\u304c\u306a\u3044\u3068\uff0c\u571f\u306f\u4e7e\u71e5\u3057\u3066\u3044\u304f\u3002\u4e7e\u71e5\u304c\u9032\u3080\u3068\uff0c\u571f\u306b\u6c34\u304c\u307e\u3063\u305f\u304f\u306a\u304f\u306a\u3063\u305f\u308f\u3051\u3067\u306f\u306a\u3044\u306e\u306b\u4f5c\u7269\u306f\u3057\u304a\u308c\u3066\u3044\u304f\u3002\u3053\u306e\u6642\uff0c\u6c34\u3092\u4e0e\u3048\u3066\u3084\u308b\u3068\u3057\u304a\u308c\u304c\u56de\u5fa9\u3059\u308b\u3053\u3068\u306f\u3088\u304f\u7d4c\u9a13\u3059\u308b\u3002\u3057\u304b\u3057\uff0c\u6c34\u304c\u4e0e\u3048\u3089\u308c\u308b\u3053\u3068\u306a\u304f\u4e7e\u71e5\u304c\u3055\u3089\u306b\u7d9a\u304f\u3068\uff0c\u4f5c\u7269\u306f\u3057\u304a\u308c\u3066\u67af\u6b7b\u3057\u3066\u3057\u307e\u3046\u3002\u305f\u3060\u3057\uff0c\u305d\u3093\u306a\u6642\u3067\u3082\u571f\u306e\u4e2d\u306e\u6c34\u304c\u5b8c\u5168\u306b\u6d88\u3048\u3066\u306a\u304f\u306a\u3063\u305f\u308f\u3051\u3067\u306f\u306a\u3044\u3002\u3053\u306e\u6642\u306e\u571f\u306e\u6c34\u5206\u91cf\u3092\u300c\u6c38\u4e45\u840e\u51cb\uff08\u3044\u3061\u3087\u3046\uff09\u70b9\u300d\u3068\u3044\u3046\uff08\u840e\u51cb\u3068\u306f\u3057\u304a\u308c\u308b\u3068\u3044\u3046\u610f\u5473) \u3002\u3053\u306e\u6642\u306e\u571f\u306e\u6c34\u306f\u975e\u5e38\u306b\u7d30\u304b\u3044\u3059\u304d\u9593\u3084\u7c98\u571f\uff08\u7c92\u5f84\u304c0.002 mm\u3088\u308a\u7d30\u304b\u3044\u571f\u306e\u7c92\u5b50\uff09\u306a\u3069\u306b\uff0c\u4f5c\u7269\u306e\u6839\u306e\u5438\u6c34\u529b\u4ee5\u4e0a\u306e\u529b\u3067\u4fdd\u6301\u3055\u308c\u3066\u3044\u308b\u3002\u305d\u306e\u305f\u3081\uff0c\u571f\u304b\u3089\u6c34\u304c\u5b8c\u5168\u306b\u306a\u304f\u306a\u3063\u3066\u3044\u306a\u3044\u306e\u306b\uff0c\u4f5c\u7269\u306f\u6c34\u3092\u5438\u53ce\u3067\u304d\u305a\u3057\u304a\u308c\u3066\u67af\u308c\u3066\u3057\u307e\u3046\u3002
\u3000Ultimately, the amount of moisture that is available to the crop in the soil is the amount of moisture at the permanent wilting point minus the amount of moisture at the field capacity, which is the state after drainage is completed. This moisture available to the crop is called effective moisture. The water remaining in the soil at the permanent wilting point is called invalid moisture because it is not available for crops.<\/p>\n\n\n\n
3. soil type and effective moisture content<\/h3>\n\n\n\n
\u3000Soil grain size and effective moisture content are very closely related (Figure 3). Coarse-grained soil has many large, thick crevices and good drainage, resulting in low water content at field capacity (Figure 3). As the soil grains become finer, the amount of water held in the soil increases due to the increase in the number of small crevices, and the amount of water in the field water capacity also increases. However, when the soil grains become finer to a certain degree, the large gaps related to drainage do not change, so the field water content does not change significantly even if the soil grains become finer, and the field water content reaches a ceiling (Figure 3).
\u3000\u4e00\u65b9\uff0c\u4f5c\u7269\u304c\u3057\u304a\u308c\u3066\u67af\u308c\u308b\u307b\u3069\u306b\u306a\u3063\u305f\u6642\u306e\u571f\u306e\u6c34\u5206\u91cf\uff0c\u3059\u306a\u308f\u3061\u6c38\u4e45\u840e\u51cb\u70b9\u306e\u6c34\u5206\u91cf\u306f\uff0c\u571f\u306e\u7c92\u304c\u7d30\u304b\u304f\u306a\u308c\u3070\u306a\u308b\u307b\u3069\u76f4\u7dda\u7684\u306b\u5897\u3048\u3066\u3044\u304f\uff08\u56f3\uff13) \u3002\u3053\u308c\u306f\uff0c\u571f\u306e\u7c92\u304c\u7d30\u304b\u304f\u306a\u308b\u307b\u3069\u7c98\u571f\u5206\u3084\u975e\u5e38\u306b\u7d30\u304b\u3044\u3059\u304d\u9593\u304c\u591a\u304f\u306a\u3063\u3066\uff0c\u305d\u3053\u306b\u5f37\u529b\u306b\u4fdd\u6301\u3055\u308c\u308b\u6c34\u5206\u91cf\u304c\u591a\u304f\u306a\u308b\u305f\u3081\u3067\u3042\u308b\u3002\u3057\u305f\u304c\u3063\u3066\uff0c\u5703\u5834\u5bb9\u6c34\u91cf\u3068\u6c38\u4e45\u840e\u51cb\u70b9\u306e\u5dee\u3067\u3042\u308b\u6709\u52b9\u6c34\u5206\u91cf\u306f\uff0c\u4e2d\u7c92\u8cea\u304f\u3089\u3044\u306e\u571f\u3067\u6700\u5927\u306b\u306a\u308b\uff08\u56f3\uff13)\u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-6.png\")
<\/figure><\/div>\n\n\n4. soil with reasonably good drainage and water retention and how to determine this<\/h3>\n\n\n\n
\u3000\u3088\u3044\u571f\u3067\u3042\u308b\uff14\u3064\u306e\u6761\u4ef6\u306e\u4e00\u3064\uff0c\uff62\u9069\u5ea6\u306b\u6392\u6c34\u304c\u3088\u304f\uff0c\u306a\u304a\u304b\u3064\u9069\u5ea6\u306b\u6c34\u5206\u3092\u4fdd\u3064\u300d\u3068\u3044\u3046\u77db\u76fe\u3059\u308b\u6761\u4ef6\u3092\u3046\u307e\u304f\u6e80\u305f\u3059\u571f\u3068\u3044\u3046\u306e\u306f\uff0c\u6975\u7aef\u306a\u7c97\u7c92\u3067\u3082\u7d30\u7c92\u3067\u3082\u306a\u3044\u4e2d\u7c92\u8cea\u306e\u571f\u3067\u3042\u308b\u3002\u4e2d\u7c92\u8cea\u306e\u571f\u306f\u6392\u6c34\u7528\u306e\u5927\u304d\u306a\u3059\u304d\u9593\u3068\uff0c\u4fdd\u6c34\u7528\u306e\u5c0f\u3055\u3044\u304c\u7d30\u304b\u3059\u304e\u306a\u3044\u3059\u304d\u9593\u306e\u4e21\u65b9\u3092\u3046\u307e\u304f\u6301\u3063\u3066\u3044\u308b\u3002\u3053\u306e\u307b\u3069\u3088\u3044\u3059\u304d\u9593\u306e\u69cb\u6210\u5272\u5408\u304c\u6392\u6c34\u3092\u826f\u597d\u306b\u3057\uff0c\u6709\u52b9\u6c34\u5206\u91cf\u3082\u591a\u304f\u4fdd\u6301\u3059\u308b\u571f\u3092\u3064\u304f\u308a\u3060\u3059\u3002
\u3000To determine if the soil is medium-grained, knead the moist soil with your thumb and forefinger and stretch it into a thread. The soil can be considered medium-grained if it can be stretched to the thickness and length of a matchstick, but not beyond that. If the soil is not matchstick-like, but rather difficult to form threads, it is considered coarse-grained soil.<\/p>\n\n\n\n
5. the size of soil particles cannot be easily changed<\/h3>\n\n\n\n
\u3000We know that medium-grained soils are reasonably good for drainage and water retention. However, the size of the soil particles is determined by the degree of weathering of the rocks from which the soil is made, which requires time enough to tell the geologic age of the soil. Turning coarse- or fine-grained soil into medium-grained soil is not something that can be done overnight. Creating gaps in the soil for water retention and drainage requires a generational effort to continue applying organic matter such as compost.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c\uff16\u56de\u3000\u3088\u3044\u571f\u306e\u6761\u4ef6\u3000\u5316\u5b66\u7684\u6027\u8cea\u2212\u305d\u306e\uff11
\u571f\u306e\u9178\u6027\u5ea6\uff08pH\uff09<\/h2>\n\n\n\n
\u4ee4\u548c\uff13 (2021) \u5e74\u300011\u6708\u53f7 (\u7b2c735\u53f7)<\/p>\n\n\n\n
\u3000I believe that good soil for crop production is soil that meets the four conditions that I presented in the first article of this series (May issue). Of these four conditions, I have discussed two that relate to the physical properties of the soil. From this month, I would like to move on to the two conditions related to the chemical properties of soil. This month, I will discuss one of them, acidity (pH).<\/p>\n\n\n\n
1. what is pH?<\/h3>\n\n\n\n
\u3000First, let's talk about the term pH. pH indicates the strength of acidity or alkalinity. pH ranges from 0 to 14, with neutral being pH 7. A pH value less than 7 is acidic, while a pH value greater than 7 is alkaline. Originally, pH was calculated from the concentration of hydrogen ions dissolved in water (strictly speaking, the degree of activity). The higher the hydrogen ion concentration, the more acidic the water is, and the lower the pH value. Conversely, the lower the hydrogen ion concentration, the greater the pH value, and the less acidic (more alkaline) the water. This is a little different from common sense, so it is easy to get confused.
\u3000For example, the difference between pH 5 and 6 is 1. The difference between pH 4 and 6 is only 2, but the hydrogen ion concentration is 100 times higher at pH 4.<\/p>\n\n\n\n
2. pH conditions suitable for crop production<\/h3>\n\n\n\n
\u3000In Japan, the optimum pH condition for good soil for crop production is in the range of 5.5 to 6.5, which is slightly on the acidic side. Of course, even within this range, the optimum pH varies slightly depending on the crop. For example, spinach, lettuce, chrysanthemum, and tomatoes prefer a pH closer to 6.5. On the other hand, balayasho (Japanese radish) prefers a pH closer to 5.5 for healthy growth, and radish and turnip are also tolerant of acidic conditions. Why is it that the optimal pH of soil in Japan is within this range? The reason is that Japanese soil tends to become acidic when left to nature.<\/p>\n\n\n\n
3. factors causing acidification of Japanese soil<\/h3>\n\n\n\n
\u3000So why does Japanese soil become acidic when left to nature? Two factors are mainly responsible: (1) rainwater and (2) chemical fertilizers, which are indispensable for crop cultivation. The two main factors are (1) rainwater and (2) chemical fertilizers, which are indispensable for crop cultivation.<\/p>\n\n\n\n
(1) Acidification by rainwater<\/h4>\n\n\n\n
\u3000\u96e8\u6c34\u306fpH7\u306e\u4e2d\u6027\u3067\u306f\u306a\u3044\u3002\u7a7a\u304b\u3089\u843d\u3061\u3066\u304f\u308b\u904e\u7a0b\u3067\uff0c\u5927\u6c17\u4e2d\u306e\u70ad\u9178\u30ac\u30b9\uff08\u4e8c\u9178\u5316\u70ad\u7d20\uff0cCO2<\/sub>\uff09\u3092\u6eb6\u304b\u3057\u8fbc\u307f\uff0c\u5929\u7136\u306e\u70ad\u9178\u6c34\u306b\u306a\u3063\u3066\u3044\u308b\u3002\u305d\u306epH\u306f5.6\u7a0b\u5ea6\u3067\u3042\u308b\u3002\u308f\u304c\u56fd\u306f\u4e16\u754c\u7684\u306b\u898b\u3066\u3082\u964d\u6c34\u91cf\u304c\u591a\u304f\uff0c\u3053\u306e\u9178\u6027\u306e\u6c34\u304c\u571f\u3092\u6d17\u3044\u6d41\u3059\u305f\u3081\uff0c\u571f\u304c\u9178\u6027\u5074\u306b\u50be\u304d\u3084\u3059\u3044\u3002
\u3000However, rainwater is naturally carbonated water when it falls in ideal, clean, unpolluted air. In areas with severe air pollution, various air pollutants are present in the atmosphere, such as sulfur oxides, nitrogen oxides, and chlorides from the oceans. These substances are also dissolved in rainwater and chemically transformed into strongly acidic substances such as sulfuric acid, nitric acid, and hydrochloric acid, respectively. This results in rainfall with a pH lower than the ideal pH of rainwater (carbonated water) of 5.6. This is acid rain (snow and fog also become acidic through the same mechanism as rain). Even ordinary rainwater, when washed away from the soil over a long period of time, causes acidification of the soil. Needless to say, acid rain (snow and fog) accelerates soil acidification.<\/p>\n\n\n\n(2) Acidification by chemical fertilizers<\/h4>\n\n\n\n
\u3000The second soil acidifying factor is chemical fertilizers. Chemical fertilizers are chemically manufactured crop nutrients. While they themselves may provide nutrients to crops, they do not have any specific detrimental effects on crops. However, if chemical fertilizers are not used properly, they can have a variety of negative effects. Acidification is one of them.
\u3000However, not all chemical fertilizers acidify the soil to the same degree. Urea, for example, is decomposed by microorganisms in the soil and then converted to ammonia for use by plants. Therefore, it acidifies the soil to a lesser degree than other fertilizers. Ammonium nitrate (ammonium nitrate) and ammonium phosphate (ammonium phosphate) are also members of this class of fertilizers.<\/p>\n\n\n\n
4. why soil acidification is bad for crop growth<\/h3>\n\n\n\n
\u3000The activity of soil microorganisms and the availability of nutrients to crops are greatly affected by soil pH (Figure 1). Table 1 summarizes the effects of soil acidification (low pH) on crop growth. Basically, soil acidification has a negative effect on crops. The most serious problem is that acidification causes aluminum, iron, manganese, and other elements to dissolve into the water in the soil (soil solution), which in turn damages crops.
\u3000\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u306f\uff0c\u901a\u5e38\uff0c\u571f\u306e\u4e2d\u306e\u7c98\u571f\u9271\u7269\u306e\u7d50\u6676\u3092\u69cb\u6210\u3057\u3066\u5b58\u5728\u3057\u3066\u3044\u308b\u3002\u3068\u3053\u308d\u304c\u571f\u306e\u9178\u6027\u5316\u306b\u3088\u3063\u3066\u5897\u3048\u305f\u6c34\u7d20\u30a4\u30aa\u30f3\u306f\u7c98\u571f\u9271\u7269\u306e\u7d50\u6676\u3092\u7834\u58ca\u3057\uff0c\u7d50\u6676\u3092\u69cb\u6210\u3057\u3066\u3044\u308b\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u3092\u571f\u58cc\u6eb6\u6db2\u306b\u6eb6\u3051\u3066\u3044\u308b\u5404\u7a2e\u306e\u967d\u30a4\u30aa\u30f3\u3068\u5165\u308c\u66ff\u308f\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u5f62\u614b\uff08\u4ea4\u63db\u6027\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\uff09\u306b\u5909\u5316\u3055\u305b\u308b\u3002\u3053\u306e\u305f\u3081\uff0cpH\u304c5\u7a0b\u5ea6\u3088\u308a\u4f4e\u4e0b\u3059\u308b\u3068\uff0c\u6025\u901f\u306b\u571f\u58cc\u6eb6\u6db2\u4e2d\u306e\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u6fc3\u5ea6\u304c\u9ad8\u307e\u308b\uff08\u56f3\uff11) \u3002\u571f\u58cc\u6eb6\u6db2\u306e\u9ad8\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u6fc3\u5ea6\u306f\uff0c\u4f5c\u7269\u306e\u6839\u306e\u7d30\u80de\u306b\u76f4\u63a5\u969c\u5bb3\u3092\u4e0e\u3048\uff0c\u990a\u5206\u5438\u53ce\u3092\u963b\u5bb3\u3059\u308b\u3002
\u3000\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u3060\u3051\u3067\u306a\u304f\uff0c\u571f\u306e\u4e2d\u306b\u591a\u304f\u542b\u307e\u308c\u3066\u3044\u308b\u9244\u3084\u30de\u30f3\u30ac\u30f3\u3082\uff0c\u9178\u6027\u5316\u3059\u308b\u3068\u6025\u306b\u571f\u58cc\u6eb6\u6db2\u306b\u6eb6\u3051\u51fa\u3057\u3066\u3044\u304f\uff08\u56f3\uff11) \u3002\u9244\u3084\u30de\u30f3\u30ac\u30f3\u306f\uff0c\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u3068\u3061\u304c\u3063\u3066\u4f5c\u7269\u306e\u5fc5\u9808\u990a\u5206\u3067\u3042\u308b\u3002\u3057\u304b\u3057\uff0c\u571f\u304c\u9178\u6027\u306b\u306a\u3063\u3066\u904e\u5270\u306b\u6eb6\u3051\u51fa\u3059\u3068\uff0c\u4f5c\u7269\u306b\u904e\u5270\u5438\u53ce\u5bb3\u3092\u4e0e\u3048\u751f\u80b2\u306b\u60aa\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u3002
\u3000Even more inconvenient is the fact that aluminum and iron are strongly bound to phosphorus, and the combined aluminum and iron phosphates are almost insoluble in water. This makes it difficult to absorb the phosphorus that is fed as fertilizer, and crops are prone to phosphorus deficiency.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-7.png\")
<\/figure><\/div>\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-8.png\")
<\/figure><\/div>\n\n\n5. proper acid amendment of soil as well.<\/h3>\n\n\n\n
\u3000You cannot tell its pH just by looking at the soil. It is practical to have the soil analyzed by soil diagnosis. If the analysis shows that the pH is lower than the optimum pH, the amount of alkaline material (calcium carbonate, etc.) needed to improve the pH to the optimum level is suggested. The acidity can be improved by giving the appropriate amount to the field and thoroughly mixing it with the soil. Conditions related to the chemical properties of the soil are relatively easy to improve, unlike the physical properties.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
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\u9178\u6027\u969c\u5bb3\u304c\u3067\u308b\u571f\u3068\u3067\u306b\u304f\u3044\u571f<\/h2>\n\n\n\n
\u4ee4\u548c\uff13 (2021) \u5e74\u300012\u6708\u53f7 (\u7b2c736\u53f7)<\/p>\n\n\n\n
\u3000\u5148\u6708\u306f\u4f5c\u7269\u751f\u7523\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6\u3067\u9069\u6b63\u306apH\uff08\u7d14\u6c34H2<\/sub>O\u3092\u4f7f\u3063\u3066\u6e2c\u5b9a\u3057\u305fpH,\u4ee5\u4e0b\u540c\u69d8\uff09\u306f5.5\u301c6.5\u306e\u7bc4\u56f2\u3067\u3042\u308b\u3068\u6307\u6458\u3057\u305f\u3002\u9069\u6b63\u7bc4\u56f2\u304c\u3084\u3084\u9178\u6027\u5074\u306b\u3042\u308b\u306e\u306f\uff0c\u308f\u304c\u56fd\u3067\u306f\u96e8\u304c\u591a\u304f\u571f\u304c\u9178\u6027\u5316\u3057\u3084\u3059\u3044\u6761\u4ef6\u306b\u3042\u308a\uff0c\u305d\u306e\u6761\u4ef6\u306b\u9069\u3057\u305f\u4f5c\u7269\u304c\u683d\u57f9\u3055\u308c\u308b\u304b\u3089\u3067\u3042\u308b\u3002\u307e\u305f\uff0c\u571f\u304c\u9178\u6027\u5316\u3057\u3066\u4f5c\u7269\u751f\u80b2\u306b\u60aa\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u8981\u56e0\u306e\u3046\u3061\uff0c\u3068\u304f\u306b\u60aa\u5f71\u97ff\u304c\u5927\u304d\u3044\u306e\u306f\u30a2\u30eb\u30df\u30cb\u30a6\u30e0(Al\uff09\u3067\u3042\u308b\u3053\u3068\u3082\u8ff0\u3079\u305f\u3002
\u3000However, there are various kinds of soils that are highly acidic with a pH lower than 5.0 but do not cause serious damage to crops. This month, we will consider why this is the case.<\/p>\n\n\n\n1. soil that allows corn to grow vigorously even in highly acidic conditions<\/h3>\n\n\n\n
\u3000First, look at Figure 1. This is the result of corn cultivation using two types of soil derived from volcanic ash widely distributed in Japan (commonly known as volcanic ash soil, or more correctly, black box soil).
\u3000The two soils on the left in Figure 1 are typical Japanese black granite soils called allophenolic black granite soils (hereafter abbreviated as A black granite soil). The name is derived from the presence of clay minerals (such as allophene and imogolite) that do not form a clear crystal structure. On the other hand, the two soils on the right are special black earths distributed in the Tohoku region, Hokkaido, and the Sea of Japan side of Honshu, and are called non-allophene black earths (hereafter abbreviated as N black earths). The main clay mineral in this soil is not allophene, but a clay mineral with a well-defined crystal structure.
\u3000The pH of the A black soil was 4.8 and that of the N black soil was 4.5, making them highly acidic soils. We compared the growth of corn plants in these soils with and without acidification with calcium carbonate (calcium carbonate), an alkaline material, after supplying sufficient lime superphosphate as a phosphorus material.
\u3000If the soil is highly acidic, as these two A black box soils are, corn growth should deteriorate unless the soil is acidified. However, strangely enough, there was no significant difference in the growth of corn in the left two A black soil, regardless of whether the soil was acidified or not. On the other hand, in the case of the two N black box soils on the right, the growth of corn plants was greatly suppressed without acidification. In other words, there were two types of soils: one in which acid damage appeared in the crop even when the soil was acidified (in the case of the two N black box soils on the right of Fig. 1), and the other in which this did not occur (in the case of the two A black box soils on the left of Fig. 1). Why is this?<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-9.jpg\")
<\/figure><\/div>\n\n\n\uff12\uff0e\u4ea4\u63db\u9178\u5ea6\uff08y1<\/sub>\uff09\u304c\u3061\u304c\u3063\u3066\u3044\u305f<\/h3>\n\n\n\n\u3000\u901a\u5e38\uff0c\u571f\u306epH\u306f\u7d14\u6c34\uff08H2<\/sub>O\uff09\u3092\u4f7f\u3063\u3066\u6e2c\u5b9a\u3057\u3066\u3044\u308b\u3002\u3057\u304b\u3057\uff0c\u3082\u3046\u4e00\u3064\u306e\u6e2c\u5b9a\u65b9\u6cd5\u3068\u3057\u3066\uff0c\u5869\u5316\u30ab\u30ea\u30a6\u30e0\uff08KCl\uff09\u6eb6\u6db2\u3092\u7528\u3044\u308b\u5834\u5408\u304c\u3042\u308b\u3002\u305d\u306e\u3068\u304d\u306fpH\uff08KCl\uff09\u3068\u8868\u793a\u3059\u308b\u3002
\u3000The idea of using potassium chloride solution to measure pH came from Gintaro Daikubara, who was the first in the world to research methods of improving soil acidity. He believed that soil acidification adversely affects crops because of aluminum ions dissolved in soil moisture (soil solution), and that the degree of adverse effect is determined by the amount of exchangeable aluminum retained in the soil. As a method to measure this, he devised an ion-exchange method in which the exchangeable aluminum retained in the soil was ion-exchanged with potassium ions in a potassium chloride solution and released into the solution.
\u3000\u571f\u304b\u3089\u5869\u5316\u30ab\u30ea\u30a6\u30e0\u6eb6\u6db2\u306b\u653e\u51fa\u3055\u308c\u305f\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306f\uff0c\u6eb6\u6db2\u306eH2<\/sub>O\u3068\u6b21\u3005\u306b\u53cd\u5fdc\u3057\u3066\u6c34\u7d20\u30a4\u30aa\u30f3\u3092\u3064\u304f\u308a\u3060\u3059\u3002\u3053\u306e\u305f\u3081\uff0c\u6c34\u7d20\u30a4\u30aa\u30f3\u6fc3\u5ea6\u304c\u6fc3\u304f\u306a\u3063\u3066\u9178\u6027\u5ea6\u304c\u5f37\u307e\u308b\u3002\u3053\u306e\u5f37\u307e\u3063\u305f\u9178\u6027\u5ea6\u3092\u30a2\u30eb\u30ab\u30ea\u6027\u306e\u6c34\u9178\u5316\u30ca\u30c8\u30ea\u30a6\u30e0\uff08\u82db\u6027\u30bd\u30fc\u30c0)\u6eb6\u6db2\u3067\u4e2d\u548c\u3057\uff0c\u305d\u306e\u4e2d\u548c\u306b\u5fc5\u8981\u306a\u6c34\u9178\u5316\u30ca\u30c8\u30ea\u30a6\u30e0\u306e\u91cf\uff08\u30df\u30ea\u30ea\u30c3\u30c8\u30eb\uff1d\u3396\uff09\u3067\uff0c\u9593\u63a5\u7684\u306b\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u3092\u6e2c\u5b9a\u3057\u3088\u3046\u3068\u3057\u305f\u3002\u3053\u306e\u3396\u5024\u3092\u4ea4\u63db\u9178\u5ea6\u3068\u3088\u3073\uff0c\u8a18\u53f7\u3092y1<\/sub>\uff08\u30ef\u30a4\u30ef\u30f3\uff09\u3068\u3057\u305f\u3002
\u3000\u56f3\uff11\u306e\u5b9f\u9a13\u3067\u7528\u3044\u305f\u4e8c\u3064\u306e\u9ed2\u30dc\u30af\u571f\u306ey1<\/sub>\u306f\uff0cA\u9ed2\u30dc\u30af\u571f\u306e\u5834\u54084.4\u3067\u3042\u3063\u305f\u306e\u306b\u5bfe\u3057\uff0cN\u9ed2\u30dc\u30af\u571f\u306f28.0\u3068\u5927\u304d\u304f\u3061\u304c\u3063\u3066\u3044\u305f\u3002\u3064\u307e\u308a\uff0cA\u9ed2\u30dc\u30af\u571f\u306f\u9178\u6027\u969c\u5bb3\u306e\u539f\u56e0\u7269\u8cea\u3067\u3042\u308b\u4ea4\u63db\u6027\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u304c\u3082\u3068\u3082\u3068\u5c11\u306a\u304f\uff0cN\u9ed2\u30dc\u30af\u571f\u306fA\u9ed2\u30dc\u30af\u571f\u306e\uff17\u500d\u8fd1\u304f\u3082\u591a\u304f\u6301\u3063\u3066\u3044\u305f\u3053\u3068\u306b\u306a\u308b\u3002
\u3000Therefore, it can be understood that corn, which is relatively tolerant to acidity, did not suffer from growth failure with the amount of exchangeable aluminum as low as that of A black soil, even if the pH was very acidic. On the other hand, if the amount of exchangeable aluminum is high, as in the case of N black soil, the amount of aluminum ions in the soil solution will increase and cause acid damage to the roots if the soil is not acidified.<\/p>\n\n\n\n\uff13\uff0e\u306a\u305c\u571f\u306b\u3088\u3063\u3066\u4ea4\u63db\u9178\u5ea6\uff08y1<\/sub>\uff09\u304c\u3061\u304c\u3046\u306e\u304b<\/h3>\n\n\n\n\u3000The reason that corn could grow without acidification even though the soil is highly acidic is because the A black box soil could not retain much exchangeable aluminum. The question is why.
\u3000This is a curious fact, but it is deeply related to the negative and positive electrostatic properties (positive and negative charge) of soil (details will be given later in this series).
\u3000A\u9ed2\u30dc\u30af\u571f\u304c\u6301\u3064\u8ca0\u8377\u96fb\u3084\u6b63\u8377\u96fb\u306f\uff0c\u5468\u308a\u306e\u571f\u58cc\u6eb6\u6db2\u306epH\u306b\u3088\u3063\u3066\u5927\u304d\u304f\u5909\u5316\u3059\u308b\uff08\u3053\u308c\u3092\u5909\u7570\u8377\u96fb\u3068\u3044\u3046) \u3002\u3053\u306e\u6027\u8cea\u3092\u3082\u3064\u8ca0\u8377\u96fb\u306f\uff0c\u571f\u304c\u9178\u6027\u306b\u50be\u304f\u3068\u305d\u308c\u4ee5\u4e0a\u9178\u6027\u5316\u3057\u306a\u3044\u3088\u3046\u306b\u4f5c\u7528\u3057\uff0c\u30d7\u30e9\u30b9\u306e\u96fb\u6c17\u3092\u5e2f\u3073\u305f\u6c34\u7d20\u30a4\u30aa\u30f3\u304c\u571f\u58cc\u6eb6\u6db2\u3078\u653e\u51fa\u3055\u308c\u306a\u3044\u3088\u3046\u81ea\u5206\u306e\u8ca0\u8377\u96fb\u306b\u9759\u96fb\u6c17\u7684\u306b\u3072\u304d\u3064\u3051\u3066\u4fdd\u6301\u3057\u305f\u72b6\u614b\u3092\u7dad\u6301\u3059\u308b\u3002\u305d\u3046\u306a\u308b\u3068\uff0c\u8ca0\u8377\u96fb\u306f\u6c34\u7d20\u30a4\u30aa\u30f3\u3067\u3075\u3055\u304c\u308c\u305f\u307e\u307e\u306a\u306e\u3067\uff0c\u7a7a\u3044\u305f\u8ca0\u8377\u96fb\u304c\u306a\u3044\u3002\u30d7\u30e9\u30b9\u306e\u96fb\u6c17\u3092\u3082\u3064\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306f\u571f\u306e\u8ca0\u8377\u96fb\u306b\u5f15\u304d\u3064\u3051\u3089\u308c\u3066\u4ea4\u63db\u6027\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u3068\u306a\u308b\u3002\u3057\u304b\u3057\uff0c\u305d\u306e\u305f\u3081\u306e\u7a7a\u3044\u305f\u8ca0\u8377\u96fb\u304c\u306a\u3044A\u9ed2\u30dc\u30af\u571f\u3067\u306f\uff0c\u4ea4\u63db\u6027\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u304c\u5b89\u5b9a\u3057\u3066\u4fdd\u6301\u3055\u308c\u308b\u5834\u6240\u304c\u306a\u304f\uff0c\u305d\u306e\u7d50\u679c\u3068\u3057\u3066\u4ea4\u63db\u9178\u5ea6\uff08y1<\/sub>\uff09\u304c\u5c0f\u3055\u304f\u306a\u308b\u3002
\u3000\u4e00\u65b9\uff0cN\u9ed2\u30dc\u30af\u571f\u306e\u8ca0\u8377\u96fb\u306fA\u9ed2\u30dc\u30af\u571f\u306e\u3088\u3046\u306a\u6027\u8cea\u304c\u306a\u304f\uff0c\u3044\u3064\u3067\u3082\u8ca0\u8377\u96fb\u3068\u3057\u3066\u6a5f\u80fd\u3057\u3066\u3044\u308b\u3002\u3053\u306e\u305f\u3081\u30d7\u30e9\u30b9\u306e\u96fb\u6c17\u3092\u5e2f\u3073\u308b\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u304c\u8fd1\u304f\u306b\u304f\u308b\u3068\uff0c\u8ca0\u8377\u96fb\u306b\u4fdd\u6301\u3055\u308c\u3066\u3044\u305f\u6c34\u7d20\u30a4\u30aa\u30f3\u3068\u30a4\u30aa\u30f3\u4ea4\u63db\u3057\u3066\uff0c\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u304c\u8ca0\u8377\u96fb\u306b\u5f15\u304d\u3064\u3051\u3089\u308c\u3066\u4fdd\u6301\u3055\u308c\u308b\u3002\u3053\u306e\u305f\u3081N\u9ed2\u30dc\u30af\u571f\u3067\u306f\u4ea4\u63db\u6027\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u304c\u5b89\u5b9a\u3057\u3066\u5b58\u5728\u3067\u304d\uff0c\u305d\u306e\u91cf\u3082\u591a\u304f\u306a\u3063\u3066\u4ea4\u63db\u9178\u5ea6\uff08y1<\/sub>\uff09\u304c\u5927\u304d\u304f\u306a\u308b\u3002<\/p>\n\n\n\n\uff14\uff0e\u4ea4\u63db\u9178\u5ea6\uff08y1<\/sub>\uff09\u306e\u6e2c\u5b9a\u306e\u91cd\u8981\u6027<\/h3>\n\n\n\n\u3000\u65e5\u672c\u306e\u571f\u306f\u9178\u6027\u5316\u3057\u3084\u3059\u3044\u3002\u3060\u304b\u3089\u6bce\u5e74\u70ad\u30ab\u30eb\u3092\u4e0e\u3048\u3066\u9178\u6027\u5316\u3092\u9632\u304c\u306d\u3070\u306a\u3089\u306a\u3044\u3068\u3057\u3070\u3057\u3070\u6307\u6458\u3055\u308c\u308b\u3002\u3053\u306e\u3053\u3068\u304c\u5f37\u8abf\u3055\u308c\u308b\u3042\u307e\u308a\u306b\uff0c\u571f\u58cc\u8a3a\u65ad\u3092\u3059\u308b\u3053\u3068\u3082\u306a\u304f\u3080\u3084\u307f\u306b\u70ad\u30ab\u30eb\u3092\u4e0e\u3048\u308b\u3053\u3068\u306b\u3064\u306a\u304c\u308a\uff0c\u7d50\u679c\u7684\u306b\u9ad8pH\u306e\u571f\u3092\u3064\u304f\u308a\u3060\u3057\u3066\u3044\u308b\u3002\u9178\u6027\u6539\u826f\u306b\u3064\u3044\u3066\uff0c\u3068\u304f\u306b\u6ce8\u610f\u3059\u3079\u304d\u571f\u304b\u3069\u3046\u304b\u3092\u898b\u5206\u3051\u308b\u306b\u306fy1<\/sub>\u3092\u6e2c\u5b9a\u3059\u308c\u3070\u3088\u3044\u3002
\u3000\u9178\u6027\u969c\u5bb3\u304c\u767a\u751f\u3057\u3084\u3059\u3044N\u9ed2\u30dc\u30af\u571f\u306f\uff0cy1<\/sub>\u304c\uff15\u4ee5\u4e0a\u3068\u3055\u308c\u3066\u3044\u308b\u3002\u4f5c\u7269\u306b\u3088\u3063\u3066\u9178\u6027\u306b\u5bfe\u3059\u308b\u5f37\u3055\uff08\u8010\u6027\uff09\u304c\u3061\u304c\u3046\u306e\u3067\uff0c\u9178\u6027\u969c\u5bb3\u304c\u767a\u751f\u3057\u3084\u3059\u3044\u571f\u304b\u3069\u3046\u304b\u306e\u5224\u5b9a\u57fa\u6e96\u306f\u4f5c\u7269\u3067\u7570\u306a\u308b\u3002\u3053\u306e\u305f\u3081\u5224\u5b9a\u57fa\u6e96\u3092\u4e00\u822c\u5316\u3059\u308b\u306e\u306f\u96e3\u3057\u3044\u3002\u3057\u304b\u3057\uff0c\u305d\u306e\u76ee\u5b89\u306e\u4e00\u3064\u3068\u3057\u3066y1<\/sub>\u304c\uff15\u4ee5\u4e0a\u304b\u3069\u3046\u304b\u3092\u63a1\u7528\u3057\u3066\u306f\u3069\u3046\u3060\u308d\u3046\u304b\u3002pH\u306e\u6e2c\u5b9a\u3068\u540c\u69d8\uff0c\u571f\u58cc\u8a3a\u65ad\u306e\u9805\u76ee\u306by1<\/sub>\u3092\u52a0\u3048\u308b\u3053\u3068\u306f\u91cd\u8981\u3060\u3068\u601d\u3046\u3002<\/p>\n\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c\uff18\u56de\u3000\u3088\u3044\u571f\u306e\u6761\u4ef6\u3000\u5316\u5b66\u7684\u6027\u8cea\u2212\u305d\u306e\uff13
\u9069\u5ea6\u306b\u542b\u307e\u308c\u308b\u4f5c\u7269\u306e\u990a\u5206<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u3000\uff11\u6708\u53f7 (\u7b2c737\u53f7)<\/p>\n\n\n\n
\u3000Of the four conditions for good soil for crop production, we have discussed three so far. This month, we begin the fourth and final condition. That is, we will consider the chemical properties of the soil, i.e., \"the soil must contain an adequate amount of nutrients for crops. The question here is what kind of nutrients are contained in crops and how much are they in moderation.<\/p>\n\n\n\n
1. 17 nutrients essential for plants (crops)<\/h3>\n\n\n\n
\u3000We humans obtain the nutrients we need from food, such as carbohydrates, fats, proteins, vitamins, and minerals (inorganic substances). In the same way, plants (crops are included in plants) also need nutrients, which we call nutrients.
\u3000\u3068\u304f\u306b\u30a2\u30fc\u30ce\u30f3\u3068\u30b9\u30bf\u30a6\u30c8\uff081939\uff09\u306f\uff0c\u6b21\u306e\uff13\u3064\u306e\u6761\u4ef6\u3092\u6e80\u305f\u3057\u305f\u990a\u5206\u3092\uff0c\u690d\u7269\u306e\u751f\u80b2\u306b\u306a\u304f\u3066\u306f\u306a\u3089\u306a\u3044\u5fc5\u9808\u990a\u5206\u3068\u5b9a\u7fa9\u3059\u308b\u3053\u3068\u3092\u63d0\u6848\u3057\u305f\u3002\u73fe\u5728\u306f\u305d\u308c\u304c\u53d7\u3051\u5165\u308c\u3089\u308c\u3066\u3044\u308b\u3002\u305d\u306e\uff13\u3064\u306e\u6761\u4ef6\u3068\u306f\uff0c
\u2460\u305d\u306e\u990a\u5206\u304c\u306a\u3051\u308c\u3070\u690d\u7269\u306f\u751f\u80b2\u3057\u7d9a\u3051\u308b\u3053\u3068\u304c\u3067\u304d\u306a\u3044\u3053\u3068\uff08\u5fc5\u8981\u6027) \uff0c
\u2461\u305d\u306e\u990a\u5206\u304c\u306a\u3051\u308c\u3070\u56fa\u6709\u306e\u6b20\u4e4f\u75c7\u304c\u3042\u3089\u308f\u308c\uff0c\u305d\u306e\u75c7\u72b6\u3092\u6b63\u5e38\u306b\u56de\u5fa9\u3055\u305b\u308b\u65b9\u6cd5\u306f\u305d\u306e\u990a\u5206\u3092\u4e0e\u3048\u308b\u3053\u3068\u4ee5\u5916\u306b\u306a\u3044\u3053\u3068\uff08\u975e\u4ee3\u66ff\u6027) \uff0c
\u2462\u305d\u306e\u990a\u5206\u304c\u690d\u7269\u306e\u6804\u990a\u306b\u76f4\u63a5\u7684\u306a\u5f79\u5272\u3092\u306f\u305f\u3057\u3066\u3044\u308b\u3053\u3068\uff08\u76f4\u63a5\u6027\uff09
\u3067\u3042\u308b\u3002\u76f4\u63a5\u7684\u306a\u5f79\u5272\u3068\u306f\uff0c\u305d\u306e\u990a\u5206\u304c\u690d\u7269\u4f53\u3092\u69cb\u6210\u3059\u308b\u6210\u5206\u3067\u3042\u308b\u304b\uff0c\u3042\u308b\u3044\u306f\uff0c\u4f53\u5185\u3067\u306e\u751f\u7406\u7684\u306a\u53cd\u5fdc\u306b\u76f4\u63a5\u304b\u304b\u308f\u308a\u3092\u3082\u3063\u3066\u3044\u308b\u3068\u3044\u3046\u610f\u5473\u3067\u3042\u308b\u3002
\u3000\u73fe\u6642\u70b9\u3067\u5fc5\u9808\u990a\u5206\u306f\u4ee5\u4e0b\u306e17\u500b\u3067\u3042\u308b\u3002\u5fc5\u9808\u990a\u5206\u306e\u3046\u3061\u690d\u7269\u304c\u6bd4\u8f03\u7684\u591a\u91cf\u306b\u8981\u6c42\u3059\u308b\u990a\u5206\u3092\u591a\u91cf\u5fc5\u9808\u990a\u5206\u3068\u3044\u3044\uff0c\u70ad\u7d20\uff0c\u6c34\u7d20\uff0c\u9178\u7d20\u306e\u307b\u304b\u306b\uff0c\u8981\u6c42\u91cf\u306e\u591a\u3044\u9806\u306b\uff0c\u7a92\u7d20\uff0c\u30ab\u30ea\u30a6\u30e0\uff0c\u30ab\u30eb\u30b7\u30a6\u30e0\uff0c\u30de\u30b0\u30cd\u30b7\u30a6\u30e0\uff0c\u30ea\u30f3\uff0c\u30a4\u30aa\u30a6\u306e\uff19\u3064\u3067\u3042\u308b(\u8868\uff11) \u3002\u70ad\u7d20\uff0c\u6c34\u7d20\uff0c\u9178\u7d20\u306f\uff0c\u5927\u6c17\u4e2d\u306e\u4e8c\u9178\u5316\u70ad\u7d20\u3084\u9178\u7d20\uff0c\u3055\u3089\u306b\uff0c\u571f\u306e\u4e2d\u306e\u6c34\uff08H2<\/sub>O\uff09\u304b\u3089\u5438\u53ce\u3067\u304d\u308b\u306e\u3067\uff0c\u5730\u7403\u4e0a\u3067\u690d\u7269\u304c\u751f\u80b2\u3059\u308b\u304b\u304e\u308a\u4e0d\u8db3\u3059\u308b\u3053\u3068\u306f\u3042\u307e\u308a\u306a\u3044\u3002\u3057\u305f\u304c\u3063\u3066\uff0c\u591a\u91cf\u5fc5\u9808\u990a\u5206\u3068\u3057\u3066\u91cd\u8981\u306a\u306e\u306f\u7a92\u7d20\u304b\u3089\u30a4\u30aa\u30a6\u307e\u3067\u306e\uff16\u7a2e\u985e\u3067\u3042\u308b\u3002\u5fc5\u9808\u990a\u5206\u3067\u6b8b\u308a\u306e\uff18\u3064\u306f\uff0c\u9244\uff0c\u5869\u7d20\uff0c\u30de\u30f3\u30ac\u30f3\uff0c\u30db\u30a6\u7d20\uff0c\u4e9c\u925b\uff0c\u9285\uff0c\u30e2\u30ea\u30d6\u30c7\u30f3\uff0c\u30cb\u30c3\u30b1\u30eb\u3067\u3042\u308b\u3002\u3053\u308c\u3089\u306f\u6bd4\u8f03\u7684\u308f\u305a\u304b\u306a\u91cf\u3057\u304b\u690d\u7269\u306b\u8981\u6c42\u3055\u308c\u306a\u3044\u306e\u3067\uff0c\u5fae\u91cf\u5fc5\u9808\u990a\u5206\u3068\u3044\u3046\uff08\u8868\uff11) \u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-9.png\")
<\/figure><\/div>\n\n\n2. the controversy and settlement of what nutrients are<\/h3>\n\n\n\n
\u3000In fact, the controversy over what is a nutrient for plants has a long history, dating back to the Greek and Roman periods. The debate began in Germany in the 19th century, settling the debate about nutrients between Thea, who believed that nutrients were organic (carbon-containing substances), and Shupe, who believed that they were inorganic (also known as minerals. The debate between Theja, who claimed that nutrients are organic (substances containing carbon), and Sprenger and Liebig, who claimed that they are inorganic (substances that do not contain carbon).
\u3000The theory that organic matter is a nutrient was strongly influenced by the \"vital energy theory\" that was prevalent throughout society at the time. According to the animate theory, organic matter was produced with the help of a unique life force that existed only in living plants and animals, and that organic matter could not be produced from inorganic matter that did not have life. This argument, however, lost its basis when Weller of Germany synthesized urea, an organic substance, from inorganic substances in 1828. Thus, the controversy was settled on the basis of Sprenger and Liebig's claim that inorganic substances are nutrients. However, the idea that organic substances are nutrients has not disappeared, but has been handed down in the spirit of organic agriculture to this day.<\/p>\n\n\n\n
3. moderate nutrient levels and soil diagnostic reference values<\/h3>\n\n\n\n
\u3000By the way, how much of these nutrients must be present in the soil in adequate amounts? Moreover, crop nutrients are not merely sufficient if they are present in the soil, but they serve as nutrients for crops only when they are present in a form that can be absorbed by the crop (this is called the availability form). Therefore, to determine whether nutrients are adequately present in the soil, it is necessary to know how much nutrients are available in the availability form. Unfortunately, this cannot be determined just by looking at the soil. It can only be determined by analysis. In other words, nothing can be known without soil diagnosis.
\u3000Soil diagnosis here refers to a series of operations in which the soil is analyzed to determine the pH level and the amount of available nutrients in the soil, to determine whether the analysis results are adequate, and to provide specific measures based on the results. The standard to judge whether the condition of soluble nutrients is adequate or not based on the analysis results is the soil diagnostic standard value. In other words, the appropriate amount of nutrients as a condition for good soil is the amount of nutrients in the soil that falls within the range of the soil diagnostic standard value.
\u3000The amount of nutrients required by crops varies greatly from crop to crop. They may also be affected by the climatic conditions of the region where the crop is grown. For this reason, there is no uniform standard value for soil diagnosis that is valid for all crops in the country. Please refer to the information published by the testing and research institutes in your area to find out the specific values of soil diagnosis standards.<\/p>\n\n\n\n
4. nutrient supplementation based on soil diagnosis results<\/h3>\n\n\n\n
\u3000If all nutrients are within the range of soil diagnostic standards, the soil is considered to have adequate nutrients. However, this does not mean that compost, chemical fertilizers, or other materials do not need to be applied to the soil. This section introduces the basic concept of nutrient supplementation based on soil diagnosis results from a case study in Hokkaido, Japan.
\u3000In Hokkaido, the \"standard yield\" is defined as the yield level that can be achieved through appropriate cultivation management under relatively favorable weather and soil conditions. Under conditions where soil nutrients are within the range of soil diagnostic standard values, the amount of nutrient supply (amount of chemical fertilizer as nutrients = amount of fertilizer applied) required to ensure this standard yield is the \"standard fertilizer application amount\" (Figure 1). It is based on the concept that the amount of nutrients required for a crop to produce the \"standard yield\" is secured from both the amount supplied by the soil and the amount supplied by chemical fertilizers and compost.
\u3000Therefore, when soil nutrients are below the soil diagnostic standard, the amount of nutrients supplied by the soil is reduced, and the reduced amount must be supplemented with compost or chemical fertilizer in addition to the standard amount of fertilizer to produce the standard yield. Conversely, if soil nutrients are above the soil diagnostic standard, the amount of nutrients supplied by the soil will increase, and the reduced amount of nutrients from the standard amount of fertilizer will be sufficient (Figure 1). As mentioned above, the Hokkaido Fertilizer Guide 2020 provides specific numerical values for each crop as to how much to increase or decrease the standard amount of fertilizer based on the results of soil diagnosis. It may be helpful for your reference.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-10.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c\uff19\u56de\u3000\u3088\u3044\u571f\u306e\u6761\u4ef6\u3000\u5316\u5b66\u7684\u6027\u8cea\u2212\u305d\u306e\uff14
\u571f\u304c\u990a\u5206\u3092\u4fdd\u6301\u3059\u308b\u3057\u304f\u307f<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74 2\/3\u6708\u5408\u4f75\u53f7 (\u7b2c738\u53f7)<\/p>\n\n\n\n
\u3000It is hard to believe that soil is electrostatically charged. However, because of this property of soil, nutrients contained in fertilizers and compost are attracted to and retained in the soil by electrostatic forces. Those who discovered the soil's ability to hold these nutrients (nutrient retention capacity) must have been surprised, too.<\/p>\n\n\n\n
1. discovery of nutrient retention capacity of soil<\/h3>\n\n\n\n
\u3000The story goes back to England about 170 years ago. At that time, chemical fertilizers were new to the world and were rarely used. Therefore, the source of nutrients for crops depended exclusively on compost produced from livestock manure. However, the ammonia contained in the manure would volatilize and lose if left unattended. To prevent this, sulfuric acid, a byproduct of coal combustion, was diluted and spread on the compost heap.
\u3000However, the sulfuric acid treatment resulted in the production of large amounts of ammonium sulfate. Thompson, a wealthy farmer in Yorkshire, northern England, wondered if the sulfuric acid treatment would actually reduce the fertilizing effect of the compost because rainwater would dissolve the ammonium sulfate and run off into the ground. Thompson asked Spence, a pharmacist with a background in chemistry, to test the veracity of his suspicions.
\u3000\u30b9\u30da\u30f3\u30b9\u306f\u8fb2\u5834\u306e\u571f\u306b\u786b\u9178\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u3092\u4e0e\u3048\u3066\u3088\u304f\u6df7\u305c\uff0c\u305d\u308c\u3092\u30ac\u30e9\u30b9\u7ba1\u306b\u8a70\u3081\u3066\u4e0a\u304b\u3089\u84b8\u7559\u6c34\uff08H2<\/sub>O\uff09\u3092\u6d41\u3057\uff0c\u4e0b\u304b\u3089\u51fa\u3066\u304d\u305f\u6d78\u900f\u6c34\u306e\u6210\u5206\u3092\u5206\u6790\u3057\u305f\u3002\u3059\u308b\u3068\uff0c\u6dfb\u52a0\u3057\u305f\u306f\u305a\u306e\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u304c\u6d78\u900f\u6c34\u304b\u3089\u6d88\u3048\uff0c\u4ee3\u308f\u308a\u306b\u30ab\u30eb\u30b7\u30a6\u30e0\u304c\u786b\u9178\u30ab\u30eb\u30b7\u30a6\u30e0\u3068\u306a\u3063\u3066\u73fe\u308c\u305f\u3002\u3053\u306e\u30b9\u30da\u30f3\u30b9\u306e\u5b9f\u9a13\u7d50\u679c\u304b\u3089\uff0c\u30c8\u30f3\u30d7\u30bd\u30f3\u306f\u571f\u304c\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u3092\u3072\u304d\u3064\u3051\u3066\u4fdd\u6301\u3057\u305f\u3068\u8003\u3048\uff0c\u4e16\u754c\u3067\u6700\u521d\u306b\u3053\u306e\u4e8b\u5b9f\u3092\u8ad6\u6587\u767a\u8868\u3057\u305f\u30021850\u5e74\u306e\u3053\u3068\u3067\u3042\u308b\u3002<\/p>\n\n\n\n\u3000Around the same time, Huxtable of Dorset, southern England, also recognized the ability of soil to purify the color and odor-causing substances in manure mixtures.
\u3000After hearing the results of these experiments at a meeting of the Royal Agricultural Society of England, Ouray followed up their experiments himself and reaffirmed that the results were true. Later, after five years of extensive experimentation, he found that the clay of the soil had the ability to attract substances. The paper by Ouray describing these findings appeared in the same issue of the same journal in which Thompson's paper appeared, but on a page behind Thompson's.
\u3000All of them, who were interested in similar phenomena in the same period, concluded that this property of the soil would play a major role in actual agriculture. Among them, Ouray even believed that this soil property was due to ion exchange occurring in the soil. However, it was not until some 40 years after his death that this idea was accepted by the public.<\/p>\n\n\n\n
2. the carrier of the soil's nutrient retention capacity<\/h3>\n\n\n\n
\u3000The results of Wei's experiments led to research on soil organic matter and clay minerals and their ability to retain nutrients, which were found to have electrically charged properties. It was found that soils can be negatively electrically charged (negative charge) or positively electrically charged (positive charge) in some cases.<\/p>\n\n\n\n
(1) Bearer of soil load (negative electricity)<\/h4>\n\n\n\n
\u3000\u571f\u306e\u8ca0\u8377\u96fb\u306e\u62c5\u3044\u624b\u306f\uff0c\u2460\u7c98\u571f\u9271\u7269\u306e\u69cb\u9020\u5909\u5316\u306b\u3088\u308b\u8377\u96fb\uff0c\u2461\u7c98\u571f\u9271\u7269\u306e\u7aef\u672b\u306b\u3067\u304d\u308b\u8377\u96fb\uff0c\u2462\u6709\u6a5f\u7269\uff08\u8150\u690d\uff09\u306e\u7aef\u672b\u306b\u3067\u304d\u308b\u8377\u96fb\u306e\uff13\u3064\u3067\u3042\u308b\u3002
\u3000\u7c98\u571f\u9271\u7269\u3068\u306f\u571f\u306e\u539f\u6599\u3067\u3042\u308b\u5ca9\u77f3\uff08\u4e00\u6b21\u9271\u7269\uff09\u304c\u7269\u7406\u7684\uff0c\u3042\u308b\u3044\u306f\u5316\u5b66\u7684\u306a\u98a8\u5316\u4f5c\u7528\u3092\u3046\u3051\u3066\u5909\u6210\u3057\uff0c\u5143\u306e\u5ca9\u77f3\u3068\u306f\u3061\u304c\u3046\u9271\u7269\uff08\u4e8c\u6b21\u9271\u7269\uff09\u3068\u306a\u3063\u305f\u3082\u306e\u3067\u3042\u308b\u3002\u57fa\u672c\u3068\u306a\u308b\u69cb\u9020\u306f\u30b1\u30a4\u7d20\u3082\u3057\u304f\u306f\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u304c\u4e3b\u4f53\u3068\u306a\u308a\uff0c\u305d\u308c\u306b\u9178\u7d20\uff0c\u6c34\u7d20\u306a\u3069\u304c\u898f\u5247\u6027\u3092\u3082\u3063\u3066\u7d50\u5408\u3057\u305f\uff11\u679a\u306e\u9762\u72b6\u306b\u306a\u3063\u3066\u3044\u308b\u3002\u3053\u3053\u3067\u306f\u30b1\u30a4\u7d20\u4e3b\u4f53\u306e\u30b7\u30fc\u30c8\uff0c\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u4e3b\u4f53\u306e\u30b7\u30fc\u30c8\u3068\u3044\u3046\u3053\u3068\u306b\u3059\u308b\u3002
\u3000\u8ca0\u8377\u96fb\u306e\u62c5\u3044\u624b\u306e\u2460\u306f\uff0c\u3053\u306e\u7c98\u571f\u9271\u7269\u306e\u7d50\u6676\uff0c\u305f\u3068\u3048\u3070\u30b1\u30a4\u7d20\u4e3b\u4f53\u306e\u30b7\u30fc\u30c8\u3067\uff0c\u30b1\u30a4\u7d20\uff08\u30d7\u30e9\u30b9\u306e\u96fb\u6c17\u3092\u5e2f\u3073\u308b\u624b\uff08\u6b63\u8377\u96fb\uff09\u306e\u6570\u304c\uff14\u3064\uff09\u304c\uff0c\u539f\u5b50\u306e\u5927\u304d\u3055\u304c\u307b\u307c\u540c\u3058\u306e\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\uff08\u6b63\u8377\u96fb\u306e\u6570\u304c\uff13\u3064\uff09\u3068\u5165\u308c\u66ff\u308f\u308b\uff08\u540c\u578b\u7f6e\u63db\u3068\u3044\u3046\uff09\u3053\u3068\u306b\u3088\u3063\u3066\u3067\u304d\u308b\uff08\u56f3\uff11) \u3002\u6b63\u8377\u96fb\uff14\u3064\u306e\u30b1\u30a4\u7d20\u306f\uff0c\u9178\u7d20\u306e\u8ca0\u8377\u96fb\uff14\u3064\u3068\u3064\u308a\u3042\u3063\u3066\u3044\u305f\u3002\u3068\u3053\u308d\u304c\uff0c\u6b63\u8377\u96fb\uff13\u3064\u306e\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u3068\u5165\u308c\u66ff\u308f\u308b\u3068\uff0c\u9178\u7d20\u306e\u8ca0\u8377\u96fb\uff11\u3064\u306b\u4f59\u5270\u304c\u3067\u308b\u3002\u3053\u306e\u4f59\u5270\u306e\u8ca0\u8377\u96fb\u306f\uff0c\u5468\u308a\u306e\u6761\u4ef6\u306b\u304b\u304b\u308f\u3089\u305a\u5e38\u306b\u8ca0\u8377\u96fb\u3068\u3057\u3066\u6a5f\u80fd\u3059\u308b\u5b89\u5b9a\u3057\u305f\u8377\u96fb\u3067\uff0c\u6c38\u4e45\u8377\u96fb\u3068\u3044\u3046\u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-12.png\")
<\/figure><\/div>\n\n\n\u3000\u8ca0\u8377\u96fb\u306e\u62c5\u3044\u624b\u306e\u2461\u3068\u2462\u306f\uff0c\u3044\u305a\u308c\u3082\u8377\u96fb\u306e\u5468\u308a\u306epH\u304c\u4e0a\u304c\u308b\u3068\u3068\u3082\u306b\u767a\u751f\u3059\u308b\u3002pH\u304c\u4e0a\u304c\u308b\u3068\u3044\u3046\u306e\u306f\uff0c\u6c34\u7d20\u30a4\u30aa\u30f3\uff08H\u207a\uff09\u304c\u6e1b\u5c11\u3057\u3066\u6c34\u9178\u30a4\u30aa\u30f3\uff08OH\u207b\uff09\u304c\u5897\u3048\u308b\u3053\u3068\u3092\u610f\u5473\u3057\u3066\u3044\u308b\u3002\u2461\u306e\u5834\u5408\u3082\u2462\u306e\u5834\u5408\u3082\uff0c\u7c98\u571f\u9271\u7269\u306e\u30b7\u30fc\u30c8\u3084\u6709\u6a5f\u7269\u306e\u7aef\u672b\u306b\u3042\u308b\u6c34\u9178\u57fa\uff08\u2212OH\uff09\u3084\u30ab\u30eb\u30dc\u30ad\u30b7\u30eb\u57fa(\u2212COOH\uff09\u306e\u7aef\u306b\u3042\u308b\u6c34\u7d20\uff08H\uff09\u304c\uff0c\u5897\u3048\u305f\u6c34\u9178\u30a4\u30aa\u30f3\u306b\u3072\u304d\u5bc4\u305b\u3089\u308c\uff0c\u7d50\u5408\u3057\u3066\u3044\u308b\u9178\u7d20\uff08O\uff09\u304b\u3089\u3072\u304d\u306f\u304c\u3055\u308c\u3066H2<\/sub>O\u3092\u3064\u304f\u308b\u3053\u3068\u3067\u8ca0\u8377\u96fb\u306b\u4f59\u5270\u304c\u767a\u751f\u3057\uff0c\u571f\u306e\u8ca0\u8377\u96fb\u3068\u3057\u3066\u6a5f\u80fd\u3059\u308b\uff08\u56f3\uff12) \u3002\u3064\u307e\u308a\uff0c\u3053\u306e\u8ca0\u8377\u96fb\u306fpH\u306e\u5f71\u97ff\u3092\u53d7\u3051\u3066\u5909\u5316\u3059\u308b\u4e0d\u5b89\u5b9a\u306a\u8377\u96fb\u3067\uff0c\u5909\u7570\u8377\u96fb\u3068\u3044\u3046\u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-13.png\")
<\/figure><\/div>\n\n\n(2) Bearer of positive charge (positive electricity)<\/h4>\n\n\n\n
\u3000\u571f\u306e\u6b63\u8377\u96fb\u306e\u62c5\u3044\u624b\u306f\uff0c\u2460\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u4e3b\u4f53\u306e\u30b7\u30fc\u30c8\u306e\u7aef\u672b\u306b\u3067\u304d\u308b\u8377\u96fb\uff0c\u2461\u6709\u6a5f\u7269\u306e\u7aef\u672b\u306b\u3067\u304d\u308b\u8377\u96fb\uff0c\u2462\u98a8\u5316\u304c\u9032\u3093\u3060\u571f\u306e\u7c98\u571f\u9271\u7269\uff08\u9244\u3084\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u306e\u9178\u5316\u7269\uff09\u306b\u3067\u304d\u308b\u8377\u96fb\u306e\uff13\u3064\u3067\u3042\u308b\u3002
\u3000\u3053\u308c\u3089\uff13\u3064\u306e\u8377\u96fb\u306f\u3044\u305a\u308c\u3082\u5468\u308a\u306epH\u304c\u4e0b\u304c\u308b\u3068\u3068\u3082\u306b\u767a\u751f\u3059\u308b\u5909\u7570\u8377\u96fb\u3067\u3042\u308b\u3002pH\u304c\u4e0b\u304c\u308b\u3068\u3044\u3046\u3053\u3068\u306f\u6c34\u7d20\u30a4\u30aa\u30f3\uff08H\u207a\uff09\u304c\u5897\u3048\u308b\u3053\u3068\u3092\u610f\u5473\u3057\u3066\u3044\u308b\u3002\u6b63\u8377\u96fb\u304c\u767a\u751f\u3059\u308b\u57fa\u672c\u7684\u306a\u3057\u304f\u307f\u306f\uff0c\u2460\u2461\u2462\u306e\u3044\u305a\u308c\u3082\u540c\u3058\u3067\uff0c\u305d\u308c\u305e\u308c\u306e\u7aef\u672b\u306b\u3042\u308b\u6c34\u9178\u57fa\uff08\u2212OH\uff09\u3084\u30ab\u30eb\u30dc\u30ad\u30b7\u30eb\u57fa\uff08\u2212COOH\uff09\u306a\u3069\u304cpH\u4f4e\u4e0b\u3067\u5897\u3048\u305f\u6c34\u7d20\u30a4\u30aa\u30f3\uff08H\u207a\uff09\u3092\u3072\u304d\u5bc4\u305b\u3066\u30aa\u30ad\u30bd\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\uff08\u2212OH2\u207a<\/sub>\uff09\u3092\u3064\u304f\u308a\uff0c\u3053\u308c\u304c\u6b63\u8377\u96fb\u3068\u3057\u3066\u6a5f\u80fd\u3059\u308b\uff08\u56f3\uff13) \u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-14.png\")
<\/figure><\/div>\n\n\n3. permanent charge and exchangeable aluminum<\/h3>\n\n\n\n
\u3000\u5148\u306b\u6307\u6458\u3057\u305f\u6c38\u4e45\u8377\u96fb\u306e\u8ca0\u8377\u96fb\u306fpH\u306e\u5f71\u97ff\u3092\u53d7\u3051\u306a\u3044\u3002\u3053\u306e\u305f\u3081\uff0c\u9178\u6027\u5316\u3057\u3066pH\u304c\u4f4e\u4e0b\u3057\u3066\u3082\u8ca0\u8377\u96fb\u3068\u3057\u3066\u6a5f\u80fd\u3057\u3066\u3044\u308b\u306e\u3067\uff0c\u9178\u6027\u6761\u4ef6\u3067\u73fe\u308c\u308b\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\uff08Al\uff13<\/sup>\u207a\uff09\u3092\u4ea4\u63db\u6027\u967d\u30a4\u30aa\u30f3\u3068\u3057\u3066\u5b89\u5b9a\u3057\u3066\u4fdd\u6301\u3067\u304d\u308b\u3002\u672c\u9023\u8f09\u7b2c\uff17\u56de\u3067\u7d39\u4ecb\u3057\u305f\u975e\u30a2\u30ed\u30d5\u30a7\u30f3\u8cea\u9ed2\u30dc\u30af\u571f\u306f\u3053\u306e\u30bf\u30a4\u30d7\u306e\u8ca0\u8377\u96fb\u3092\u6301\u3063\u3066\u304a\u308a\uff0c\u4f5c\u7269\u306e\u9178\u6027\u969c\u5bb3\u306e\u539f\u56e0\u3068\u306a\u308b\u4ea4\u63db\u6027\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u3092\u591a\u304f\u4fdd\u6301\u3067\u304d\u305f\u3002\u30c8\u30a6\u30e2\u30ed\u30b3\u30b7\u306b\u9178\u6027\u969c\u5bb3\u304c\u767a\u751f\u3057\u305f\u306e\u306f\u3053\u306e\u305f\u3081\u3067\u3042\u308b\u3002
\u3000On the other hand, allophenic black box soils are predominantly mutagenically charged from organic matter and become positively charged upon acidification. Exchangeable aluminum, which has the same positive charge, repels the positive charge of the soil and cannot exist stably. Therefore, it can be understood that the allophenolic black box soil did not cause acid damage to the corn. This is a very interesting phenomenon.<\/p>\n\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff11\u7ae0\u2212 \u4f5c\u7269\u306b\u3068\u3063\u3066\u3088\u3044\u571f\u3067\u3042\u308b\u305f\u3081\u306e\u6761\u4ef6
\u7b2c10\u56de\u3000\u3088\u3044\u571f\u306e\u6761\u4ef6\u306e\u307e\u3068\u3081
\u2212\u3069\u3093\u306a\u571f\u3067\u3082\u5fc5\u305a\u3088\u304f\u306a\u308b\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u3000\uff14\u6708\u53f7 (\u7b2c739\u53f7)<\/p>\n\n\n\n
\u3000It has been a year since I began writing this series of articles in last May's issue. Over the past nine articles, we have discussed four conditions that must be met for soil to be good for crops. These four conditions and specific target values were described in the first article. From Part 2 to Part 9, each of these conditions and their target values were explained. This issue is a summary of these articles. I would like to review the relationship between the concept of good soil and soil cultivation.<\/p>\n\n\n\n
1. what is soil preparation in the first place?<\/h3>\n\n\n\n
\u3000When farmers, as well as readers of this magazine, and others involved in agriculture discuss crop production and talk about soil, the word \"soil preparation\" always comes up. The final response is something like, \"Soil preparation means the application of organic matter such as compost. The conclusion is that no matter what kind of soil or what kind of crops are grown, the first step in \"soil preparation\" is to apply compost, and if that \"soil preparation\" is carried out, it will lead unconditionally to good results.
\u3000\u3053\u306e\u3088\u3046\u306a\u300c\u571f\u3065\u304f\u308a\u300d\u306b\u5bfe\u3059\u308b\u56fa\u5b9a\u6982\u5ff5\u306b\u5bfe\u3057\u3066\uff0c\u306a\u3093\u3068\u3082\u3044\u3048\u306a\u3044\u9055\u548c\u611f\u304c\u3042\u308b\u3002\u305d\u3093\u306a\u5358\u7d14\u306a\u8a71\u3067\u3042\u308b\u306a\u3089\u3070\uff0c\u3053\u306e\u4e16\u306e\u4e2d\u3067\u4f5c\u7269\u751f\u7523\u306e\u52a3\u308b\u571f\u306f\uff0c\u305d\u306e\u3046\u3061\u306a\u304f\u306a\u3063\u3066\u3057\u307e\u3046\u3068\u601d\u3046\u304b\u3089\u3060\u3002\u8981\u3059\u308b\u306b\u5806\u80a5\u3092\u65bd\u7528\u3059\u308c\u3070\u3088\u304f\u306a\u308b\u306e\u3060\u304b\u3089\u3002\u3000
\u3000I consider \"soil building\" to be a practical activity to improve the soil of a target field to a soil that is good for crop production. In order to do so, it is necessary to clarify what factors in the soil of the field are inhibiting the growth of crops and to what extent. In other words, it is necessary to clarify which of the \"four conditions for good soil\" described in this series of articles is the greatest inhibitory factor to the growth of crops. Then, the practice of \"soil cultivation\" is the procedure of implementing measures to improve the conditions that have become the growth-inhibiting factors.<\/p>\n\n\n\n
2. does good soil guarantee a high yield?<\/h3>\n\n\n\n
\u3000In reality, however, there is more at stake. Crop growth and yield are not determined solely by whether the soil on the farm is good for crop production.
\u3000Suppose there is a potato field with the best soil in Japan that satisfies all the \"four conditions for good soil\" through diligent improvement. However, no matter how good the soil is, if the temperature does not rise in summer, for example, the productivity (yield) of the potato field will be drastically reduced due to cold damage. Even if the weather is good, if the fertilizer is applied incorrectly, the potatoes will not produce well. Experienced farmers will be able to produce much higher yields than I, an amateur, can.
\u3000Crop productivity of soil and crop productivity of farmland have different dimensions. No matter how good the soil is for crop cultivation, crop productivity of farmland depends on many factors other than soil, such as weather, topography, site environment, fertilizer application and cultivation techniques, as well as the type of crop grown and the variety of the same crop (Figure 1).<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-15.png\")
<\/figure><\/div>\n\n\n3. soil is one of the factors that determine the crop productivity of farmland<\/h3>\n\n\n\n
\u3000In order for soil to have high crop productivity, it must satisfy all of the \"four conditions for good soil,\" as described in this series of articles. However, it cannot be said that farmland with \"good soil\" that satisfies these four conditions will always produce a high crop yield. This is because \"good soil\" is only one of many factors that determine the productivity of farmland, as shown in Figure 1.
\u3000The more we value the soil, the more we feel that the soil always determines crop production. As a result, it is often said that \"soil cultivation\" is the most important factor in \"improving crop productivity. Of course, there are many such cases. However, if we assume that soil is the only factor that determines crop production on farmland, we will lose sight of the real impediments to crop production. We must not forget that many factors are interrelated in determining the crop productivity of farmland.
\u3000The important thing is to be able to consider from a broad perspective what factors are responsible for the poor growth of crops grown on the farm. It would be a pity for the soil to blame the soil for all the causes of various phenomena, such as poor growth of crops. That is an overestimation of the soil. Before we assume that the soil is the cause, it is important to consider the factors that contribute to poor growth, and to accurately gather the factors that hinder growth.<\/p>\n\n\n\n
\uff14\uff0e\uff62\u6728\u3092\u690d\u3048\u305f\u4eba\u300d\u306e\u8a71
\u3000\u3000\u3000\u3000\u2212\u3069\u3093\u306a\u571f\u3067\u3082\u5fc5\u305a\u3088\u304f\u306a\u308b<\/h3>\n\n\n\n
\u3000I will never forget the words of my former teacher when I was a student: \"Any soil can be made better. This is because I believe that even soil with many shortcomings will one day improve if we find out which of the \"four conditions for good soil\" are the factors that inhibit the growth of crops in that soil, and then do our best to improve those factors.
\u3000\u3068\u308a\u308f\u3051\u571f\u306e\u7269\u7406\u7684\u6027\u8cea\u306b\u304b\u304b\u308f\u308b\u6761\u4ef6\u306e\u672c\u8cea\u7684\u306a\u6539\u826f\u306f\uff0c\uff62\u5806\u80a5\u3092\u3084\u308c\u3070\u3088\u304f\u306a\u308b\u300d\u3068\u3044\u3046\u3088\u3046\u306a\u4e00\u671d\u4e00\u5915\u3067\u3067\u304d\u308b\u3082\u306e\u3067\u306f\u306a\u3044\u3002\u305d\u306e\u6539\u5584\u5bfe\u7b56\u3092\uff0c\u89aa\u2212\u5b50\u2212\u5b6b\u3068\u4e16\u4ee3\u3092\u8d85\u3048\u3066\u7d99\u7d9a\u3057\u306a\u3051\u308c\u3070\uff0c\u304a\u305d\u3089\u304f\u5b9f\u73fe\u3067\u304d\u306a\u3044\u3060\u308d\u3046\u3002\u554f\u984c\u306f\uff0c\u305d\u308c\u307e\u3067\uff0c\u3042\u304d\u3089\u3081\u308b\u3053\u3068\u306a\u304f\u5026\u307e\u305a\u305f\u3086\u307e\u305a\uff0c\u6539\u5584\u306e\u52aa\u529b\u3092\u6301\u7d9a\u3067\u304d\u308b\u304b\u3069\u3046\u304b\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
\u3000There is a French literary figure named Jean Giono. The soil in the Provence region of southern France, where he was born, is often so barren that the surface soil is thin and marble (limestone) is readily visible (Figure 2). However, he never left his birthplace throughout his life, loving the land and writing his literary works there. One of his best-known works is \"The Man Who Planted Trees,\" which is well known. It is the story of Elz\u00e9ard Bouffier, who planted trees on the barren soil of Provence, restored forests and rivers, and even restored the moisture to people's hearts.
\u3000Selflessly and without asking for anything in return, day in and day out, he drilled holes in the barren, marble-covered soil and planted acorns in them. This act transformed the barren land into a land fit for people to lead healthy lives, both physically and mentally. I believe that with a sustained selfless practice like Bouffier's, any harsh, poor soil can be transformed into soil that can produce crops and in which people can live richly in mind and body.
\u3000What is necessary is to clarify what factors of the soil need to be improved and how, and then to continue with the improvement measures. We hope that you will utilize the \"Four Conditions for Good Soil\" to find these factors. To change bad soil into good soil for crops requires work like bouffier. Simply applying compost may miss the point.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-16.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff12\u7ae0\u2212 \u5806\u80a5\u3068\u5316\u5b66\u80a5\u6599
\u7b2c11\u56de\u3000\u5806\u80a5\u306f\u990a\u5206\u79fb\u8ee2\u8cc7\u6750\u3068\u3057\u3066\u767b\u5834\u3057\u305f
\u2212\u990a\u5206\u306e\u88dc\u7d66\u65b9\u6cd5\u3092\u8003\u3048\u308b\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u3000\uff15\u6708\u53f7 (\u7b2c740\u53f7)<\/p>\n\n\n\n
\u3000Starting with this issue, \"No More Soil\" will be renewed. In the past 10 articles, we have discussed the four conditions for good soil for crops. In the next 10 articles, we will discuss compost, chemical fertilizers, organic farming, and the role of soil. This time, we will look back at the history of compost, which was invented and used to replenish farmland with nutrients in the days before chemical fertilizers were available.<\/p>\n\n\n\n
1. nutrient replenishment is necessary to maintain soil fertility<\/h3>\n\n\n\n
\u3000It is believed that humans began farming about 10,000 years ago. Since then, when crops are grown and harvested on farmland, the nutrients in the soil are absorbed by the crops and taken out of the farmland with the harvest. If nutrients are not replenished, the crop nutrients in the soil will be depleted and the crop cannot be grown. Therefore, replenishment of nutrients was essential for the sustainable cultivation of crops on farmland.
\u3000How exactly to supply nutrients was the main concern. The only way to recover nutrients from the soil was to collect materials around us, such as leaf litter from forests, mud from rivers and lakes, fallen leaves, fallen branches, underbrush from forests, wild grasses, grass and tree ashes, seaweed, and manure from people and livestock. This nutrient transfer process was very labor intensive and time consuming.<\/p>\n\n\n\n
2. compost conceived as a nutrient transfer material<\/h3>\n\n\n\n
\u3000The most powerful material ever conceived for recovering crop nutrients from the soil and transferring the recovered nutrients to another location was compost. There were two ways to recover nutrients from the soil. One was the conventional method of cutting plants that grow outside the farmland (wild grasses, weeds, etc.), collecting fallen leaves and branches, and undergrowth from the mountains and forests, and letting them accumulate and decompose to make compost. The other method is to feed livestock with plants that can be used as fodder (wild grasses and pasture grasses), and collect the nutrients absorbed by the plants in the soil in the form of livestock manure for composting.
\u3000European farmers, in particular, realized that the use of livestock was much more labor-saving than collecting materials from outside the farmland. Therefore, they actively promoted nutrient recovery and composting through the use of livestock and developed a crop rotation system. The culmination of these efforts was the four-year crop rotation known as the Norfolk farming method.<\/p>\n\n\n\n
3. intensive crop rotation before the advent of chemical fertilizers<\/h3>\n\n\n\n
\u3000\u30e8\u30fc\u30ed\u30c3\u30d1\u3067\u306e\u8f2a\u4f5c\u306e\u521d\u671f\u306f\u5358\u7d14\u306b\u8fb2\u5730\u3092\u4e8c\u5206\u3057\uff0c\u4e00\u65b9\u306f\u4f5c\u7269\u683d\u57f9\u306b\u7528\u3044\uff0c\u4ed6\u65b9\u306f\u4f5c\u7269\u683d\u57f9\u3092\u4f11\u3080\uff08\u4f11\u9591\u3068\u3044\u3046\uff09\u3053\u3068\u3067\uff0c\u571f\u306e\u4e2d\u306e\u990a\u5206\u306e\u56de\u5fa9\u3092\u81ea\u7136\u306b\u307e\u304b\u305b\u308b\u3068\u3044\u3046\u4e8c\u5703\u5f0f\u8f2a\u4f5c\u3067\u3042\u3063\u305f\u3002\u305d\u306e\u5f8c\uff0c\u4e09\u5703\u5f0f\uff0c\u7a40\u8349\u5f0f\u3068\u767a\u5c55\u3057\uff0c\u30ce\u30fc\u30d5\u30a9\u30fc\u30af\u8fb2\u6cd5(\u8f2a\u683d\u5f0f\uff09\u306b\u305f\u3069\u308a\u7740\u3044\u305f\uff08\u56f3\uff11) \u3002\u305d\u308c\u307e\u3067\u306e\u8f2a\u4f5c\u3067\u3082\uff0c\u5171\u6709\u5730\u3084\u6c38\u4e45\u653e\u7267\u5730\u3067\u653e\u7267\u3055\u308c\u308b\u5bb6\u755c\u306e\u3075\u3093\u5c3f\u3092\u5229\u7528\u3057\u305f\u3002\u3057\u304b\u3057\uff0c\u653e\u7267\u5730\u3084\u8349\u5730\u3067\u5bb6\u755c\u3092\u98fc\u990a\u3059\u308b\u3068\uff0c\u305d\u3053\u3067\u6392\u6cc4\u3055\u308c\u308b\u5bb6\u755c\u3075\u3093\u5c3f\u306e\u56de\u53ce\u7387\u304c\u4f4e\u4e0b\u3059\u308b\u3068\u3044\u3046\u96e3\u70b9\u304c\u3042\u3063\u305f\u3002\u3055\u3089\u306b\uff0c\u79cb\u304b\u3089\u51ac\u306b\u304b\u3051\u3066\u306e\u671f\u9593\u306f\u91ce\u8349\u3084\u7267\u8349\u306e\u751f\u80b2\u304c\u8870\u3048\u308b\u305f\u3081\uff0c\u5bb6\u755c\u3092\u8d8a\u51ac\u3055\u305b\u308b\u306e\u306b\u5341\u5206\u306a\u98fc\u6599\u304c\u78ba\u4fdd\u3067\u304d\u306a\u304b\u3063\u305f\u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-17.png\")
<\/figure><\/div>\n\n\n\u3000The Norfolk farming method expanded farmland by eliminating all communal grazing land and fallow, and ensured fodder production by incorporating two crops for livestock fodder (fodder turnips and red clover) into a four-year crop rotation. For sowing fodder turnips, a strip sowing method was introduced using a strip sowing machine developed by agricultural experimenter Tal. This made it possible to use a weed control tiller and stabilize the production of fodder turnips. Red clover is expected to fix nitrogen by rhizobium bacteria that live in symbiosis with the roots, and was effective in increasing the nitrogen fertility of the soil. This has led to increased fodder production, and has made it possible to keep a large number of livestock and to keep them in sheds even during the winter. Keeping livestock in sheds increased the manure collection rate and dramatically increased the amount of manure produced. This has led to an increase in the amount of manure applied to grain-producing fields, which in turn has helped to maintain high soil nutrient fertility (Figure 2). Thus, an agricultural method based on nutrient cycling using livestock manure was established, and a super-intensive crop rotation was realized at that time.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-18.png\")
<\/figure><\/div>\n\n\n\u3000There is a saying in the Flemish region of mainland Europe across from Norfolk, England (present-day southern Netherlands to western Belgium and northern France): \"Without feed there is no livestock, without livestock there is no fertilizer, and without fertilizer there is no harvest. This saying eloquently describes the major role of manure as a nutrient transfer material for maintaining crop production in European crop rotation.
\u3000The Norfolk farming system transformed wheat production. Although Norfolk is a small region with only 41 TP3T of the area of England (one of the four constituent kingdoms of the United Kingdom), the introduction of the Norfolk farming method covered 901 TP3T of the entire England at that time in terms of wheat seed production (Iinuma, 1967).<\/p>\n\n\n\n
4. Japanese View of Composting: Tradition of the Supremacy of Mature Compost<\/h3>\n\n\n\n
\u3000Rice is the staple food of Japan. Rice is produced from rice, which is grown in paddy fields. Paddy fields have a wonderful mechanism whereby a significant portion of the nutrients absorbed by the rice can be recovered naturally after the rice is harvested. For example, the nutrients contained in irrigation water naturally replenish the rice. In addition, the watering of rice paddies changes phosphorus and iron into a water-soluble form, which is then absorbed by the rice plants. Thanks to a variety of other factors, the natural supply of nutrients in paddy fields is high. For this reason, the degree of nutrient wastage due to crop cultivation is smaller than in field soils. This can be understood from the fact that at the height of Norfolk agriculture in the 19th century, wheat seed yield was about 1.7 t\/ha, while rice seed yield was already 1.8 t\/ha at the end of the 16th century when the Taikoh land survey was conducted, almost equal to that of Norfolk agriculture (Takahashi et al. 1991).
\u3000In Japanese agriculture, livestock were mainly used as labor. Therefore, the number of livestock kept by farmers was small, and composts were generally produced by depositing ina straw or wheat straw and allowing them to ripen without including livestock manure. These composts, which do not contain livestock manure, are only fully ripened composts, and their effects as nutrients are difficult to be seen (the reasons for this will be explained later). The reason why the supremacy of fully ripe compost is emphasized in Japan is probably the result of the inheritance of such a tradition. We can sense the essential difference between paddy field agriculture in Japan and nutrient-recycling agriculture in Europe.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff12\u7ae0\u2212 \u5806\u80a5\u3068\u5316\u5b66\u80a5\u6599
\u7b2c12\u56de\u3000\u5806\u80a5\u306e\u52b9\u679c\u306e\u73fe\u308c\u65b9\u3068\u571f\u306e\u6761\u4ef6
\u2212\u571f\u306e\u9ed2\u3055\u304c\u6c7a\u3081\u624b\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u3000\uff16\u6708\u53f7 (\u7b2c741\u53f7)<\/p>\n\n\n\n
\u3000In the previous issue, I reviewed the history of how, in the days before the advent of chemical fertilizers, farmers overcame the difficult problem of supplying nutrients to farmland by devising a material called compost. I also mentioned the difference in the way of farming between the fields in Europe and the rice paddies in Japan, which led to a difference in the way of thinking about compost. Even after the advent of chemical fertilizers, compost is expected to have various effects. However, these various effects do not occur in all soil types without exception. Let us consider what are the conditions of soil that cause differences in the manifestation of these effects.<\/p>\n\n\n\n
1. expected effects of compost<\/h3>\n\n\n\n
\u3000Compost is expected to have three major effects (Table 1). (1) as a nutrient, (2) as a stable organic matter that is relatively resistant to decomposition, and (3) as a source of living organisms. It is often said that composting will automatically produce all three effects at the same time. This is probably the reason why people think that compost improves the soil. However, these three effects are \"expected effects\" and do not always appear.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-19.png\")
<\/figure><\/div>\n\n\n\uff11\uff09\u990a\u5206\u3068\u3057\u3066\u306e\u52b9\u679c<\/h4>\n\n\n\n
\u3000\u307e\u305a\u306f\uff0c\u990a\u5206\u3068\u3057\u3066\u306e\u52b9\u679c\u3067\u3042\u308b\u3002\u5806\u80a5\u3092\u4e0e\u3048\u308b\u3053\u3068\u3067\u76f4\u63a5\u7684\u306b\u671f\u5f85\u3067\u304d\u308b\u52b9\u679c\u306f\uff0c\u3053\u306e\u52b9\u679c\u3067\u3042\u308b\u3002\u5177\u4f53\u7684\u306b\u306f\uff0c\u2460\u591a\u91cf\u8981\u7d20\uff0c\u3068\u308a\u308f\u3051\u4e09\u8981\u7d20(\u7a92\u7d20\uff0c\u30ea\u30f3\uff0c\u30ab\u30ea\u30a6\u30e0\uff09\u306e\u4f9b\u7d66\u6e90\uff0c\u2461\u5fae\u91cf\u8981\u7d20\u306e\u4f9b\u7d66\u6e90\uff0c\u2462\u3086\u3063\u304f\u308a\u3068\u52b9\u679c\u304c\u3042\u3089\u308f\u308c\u308b\u80a5\u6599\uff08\u7de9\u52b9\u6027\u80a5\u6599\uff09\u3068\u3057\u3066\u306e\u52b9\u679c\uff0c\u2463\u690d\u7269\u30db\u30eb\u30e2\u30f3\u306e\u4f9b\u7d66\u6e90\uff0c\u306a\u3069\u3067\u3042\u308b\u3002
\u3000\u3053\u308c\u3089\u306e\u52b9\u679c\u306e\u3046\u3061\uff0c\u571f\u306e\u6761\u4ef6\u306b\u304b\u304b\u308f\u3089\u305a\uff0c\u5806\u80a5\u3092\u4e0e\u3048\u308b\u3053\u3068\u3067\u52b9\u679c\u304c\u78ba\u5b9f\u306b\u671f\u5f85\u3067\u304d\u308b\u306e\u306f\uff0c\u2460\u306e\u4e09\u8981\u7d20\u80a5\u6599\u3068\u3057\u3066\u306e\u52b9\u679c\u3067\u3042\u308b\u3002\u901a\u5e38\u306e\u7551\u3084\u6c34\u7530\u306e\u571f\u3067\uff0c\u7a92\u7d20\uff0c\u30ea\u30f3\uff0c\u30ab\u30ea\u30a6\u30e0\u306e\u3044\u305a\u308c\u3082\u304c\u4f5c\u7269\u751f\u7523\u306e\u5236\u9650\u56e0\u5b50\u3068\u306a\u3089\u306a\u3044\u3068\u3044\u3046\u571f\u306f\u8003\u3048\u306b\u304f\u3044\u304b\u3089\u3067\u3042\u308b\u3002\u307e\u305f\uff0c\u2462\u7de9\u52b9\u6027\u80a5\u6599\u3068\u3057\u3066\u306e\u50cd\u304d\u3082\uff0c\u571f\u306e\u6761\u4ef6\u306b\u304b\u304b\u308f\u3089\u305a\u671f\u5f85\u3067\u304d\u308b\u3002\u305d\u308c\u306f\uff0c\u5806\u80a5\u304c\u571f\u306b\u4e0e\u3048\u3089\u308c\u305f\u5f8c\uff0c\u571f\u306e\u4e2d\u306e\u52d5\u7269(\u30c8\u30d3\u30e0\u30b7\uff0c\u30ef\u30e9\u30b8\u30e0\u30b7\uff0c\u30df\u30df\u30ba\u306a\u3069\uff09\u3084\u5fae\u751f\u7269(\u7d30\u83cc\uff0c\u653e\u7dda\u83cc\uff0c\u7cf8\u72b6\u83cc\u306a\u3069\uff09\u306a\u3069\u304c\u5354\u529b\u3057\u3066\u5806\u80a5\u3092\u5206\u89e3\u3057\uff0c\u305d\u306e\u5206\u89e3\u306b\u3068\u3082\u306a\u3063\u3066\u5806\u80a5\u304b\u3089\u990a\u5206\u304c\u5f90\u3005\u306b\u653e\u51fa\u3055\u308c\u308b\u304b\u3089\u3067\u3042\u308b\u3002\u5806\u80a5\u3092\u9023\u7528\u3059\u308c\u3070\uff0c\u7d2f\u7a4d\u7684\u3067\u6301\u7d9a\u7684\u306a\u990a\u5206\u52b9\u679c\u3082\u671f\u5f85\u3067\u304d\u308b\u3002
\u3000However, the effect of (2) as a trace element fertilizer cannot be expected in paddy fields. This is because trace elements are dissolved in irrigation water in rice paddies, and the amount of trace elements supplied by irrigation water, which is taken up in large quantities during rice cultivation, is large. Even if the compost contains trace elements, the limited amount of trace elements supplied by the compost will not be equal to the natural supply from the irrigation water.
\u3000It is not yet well known how effective the plant hormones (4) can actually be in fields and rice paddies with a history of cultivation. However, it is likely to be effective when the surface soil containing organic matter is completely removed and the subsoil containing little organic matter is used as the cropping soil, as is the case in cultivated land.<\/p>\n\n\n\n
(2) Effect as stable organic matter<\/h4>\n\n\n\n
\u3000The second expected effect is as stable organic matter. Stable organic matter is organic matter that remains in the soil after being decomposed to some extent by animals and microorganisms, and is relatively difficult to decompose. This becomes the substance known as soil organic matter (humus), which gives the soil its black color.
\u3000\u5806\u80a5\u304c\u571f\u306e\u4e2d\u306b\u3059\u304d\u8fbc\u307e\u308c\u308b\u3068\uff0c\u5806\u80a5\u306e\u4e2d\u306e\u5206\u89e3\u3055\u308c\u3084\u3059\u3044\u6709\u6a5f\u7269\u306f\uff0c\u5206\u89e3\u3055\u308c\u308b\u3053\u3068\u3067\u990a\u5206\u7684\u52b9\u679c\u3092\u73fe\u3059\u3002\u4e00\u65b9\uff0c\u6bd4\u8f03\u7684\u5206\u89e3\u3055\u308c\u306b\u304f\u3044\u305f\u3081\u306b\u571f\u306b\u6b8b\u3063\u305f\u6709\u6a5f\u7269\u306f\uff0c\u571f\u306e\u4e2d\u306b\u3082\u3068\u3082\u3068\u3042\u3063\u305f\u6709\u6a5f\u7269\u3068\u3068\u3082\u306b\u5b89\u5b9a\u3057\u305f\u6709\u6a5f\u7269\u3068\u3057\u3066\u306e\u52b9\u679c\u3092\u767a\u73fe\u3059\u308b\u3002
\u3000\u305d\u306e\u52b9\u679c\u306b\u306f\uff0c\u2460\u571f\u306e\u7269\u7406\u7684\u306a\u6027\u8cea\uff0c\u305f\u3068\u3048\u3070\u571f\u306e\u3059\u304d\u9593\u306e\u5927\u304d\u3055\u3084\u305d\u306e\u5272\u5408\uff08\u5b54\u9699\u5206\u5e03) \uff0c\u6392\u6c34\u306e\u3057\u3084\u3059\u3055\uff08\u900f\u6c34\u6027) \uff0c\u6c34\u6301\u3061\u306e\u3088\u3055\uff08\u4fdd\u6c34\u6027) \uff0c\u7a7a\u6c17\u306e\u901a\u308a\u3084\u3059\u3055\uff08\u901a\u6c17\u6027) \uff0c\u8015\u3057\u3084\u3059\u3055\uff08\u6613\u8015\u6027\uff09\u306a\u3069\u306e\u6539\u826f\uff0c\u2461\u990a\u5206\u4fdd\u6301\u80fd\u306e\u5897\u52a0\uff0c\u2462\u6709\u5bb3\u7269\u306e\u6291\u5236\uff0c\u305f\u3068\u3048\u3070\uff0c\u6709\u6a5f\u7269\u304c\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u3068\u7d50\u5408\u3059\u308b\u3068\uff0c\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u306e\u6709\u5bb3\u306a\u50cd\u304d\u3092\u6291\u3048\u308b\u305f\u3081(\u30ad\u30ec\u30fc\u30c8\u4f5c\u7528\u3068\u3044\u3046) \uff0c\u30a2\u30eb\u30df\u30cb\u30a6\u30e0\u304c\u30ea\u30f3\u3068\u7d50\u5408\u3057\u306b\u304f\u304f\u306a\u308b\u3002\u305d\u306e\u7d50\u679c\uff0c\u30ea\u30f3\u306e\u990a\u5206\u52b9\u679c\u304c\u51fa\u3084\u3059\u304f\u306a\u308b\u3068\u3044\u3063\u305f\u52b9\u679c\uff0c\u2463\u5fae\u91cf\u8981\u7d20\u306f\u6c34\u306b\u6eb6\u3051\u306b\u304f\u3044\u5f62\u614b\u3067\u3042\u308b\u3053\u3068\u304c\u591a\u3044\u3002\u3057\u304b\u3057\uff0c\u6709\u6a5f\u7269\u304c\u5206\u89e3\u3055\u308c\u308b\u306b\u3068\u3082\u306a\u3044\u4e8c\u9178\u5316\u70ad\u7d20\uff08CO2<\/sub>\uff09\u304c\u653e\u51fa\u3055\u308c\uff0c\u3053\u308c\u304c\u6c34\u306b\u6eb6\u3051\u3066\u70ad\u9178\u6c34\u3068\u306a\u3063\u3066\u5fae\u91cf\u8981\u7d20\u3092\u6eb6\u3051\u3084\u3059\u304f\u3059\u308b\u50cd\u304d\uff0c\u3055\u3089\u306b\u2464\u6709\u6a5f\u7269\u306e\u6301\u3064\u74b0\u5883\u5909\u5316\u3092\u3084\u308f\u3089\u3052\u308b\u4f5c\u7528\uff08\u7de9\u885d\u529b\uff09\u306a\u3069\u304c\u8003\u3048\u3089\u308c\u308b\u3002
\u3000However, these various expected effects of compost as stable organic matter appear only when the organic matter content of a given soil is less than a certain criterion (ranging from 2 to 5%, depending on the soil), and no effect can be expected if it is higher (Yamane, 1981). This is because in soils with high organic matter content, the physical properties of the soil are less likely to be a limiting factor in crop production, since the soil originally contains more stable organic matter (humus).<\/p>\n\n\n\n\uff13\uff09\u751f\u7269\u306e\u4f9b\u7d66\u6e90\u3068\u3057\u3066\u306e\u52b9\u679c<\/h4>\n\n\n\n
\u3000\u4e09\u3064\u76ee\u306e\u52b9\u679c\u306f\u751f\u7269\u306e\u7d66\u6e90\u3068\u3057\u3066\u306e\u52b9\u679c\u3067\u3042\u308b\u3002\u5806\u80a5\u4e2d\u306b\u306f\u591a\u304f\u306e\u751f\u7269\uff08\u30df\u30df\u30ba\u306a\u3069\u306e\u5c0f\u52d5\u7269\u3084\u5fae\u751f\u7269\u306a\u3069\uff09\u304c\u751f\u606f\u3057\u3066\u3044\u308b\u3002\u5806\u80a5\u3092\u4e0e\u3048\u308b\u3053\u3068\u306f\uff0c\u571f\u306e\u4e2d\u306b\u3053\u308c\u3089\u306e\u751f\u7269\u3092\u4f9b\u7d66\u3059\u308b\u3053\u3068\u306b\u306a\u308b\u306e\u3067\uff0c\u305d\u306e\u4f9b\u7d66\u6e90\u3068\u3057\u3066\u306e\u52b9\u679c\u304c\u671f\u5f85\u3067\u304d\u308b\u3002
\u3000\u3057\u304b\u3057\uff0c\u3053\u306e\u52b9\u679c\u3082\u5806\u80a5\u3092\u4e0e\u3048\u308b\u571f\u304c\u901a\u5e38\u306e\u571f\u3067\u3042\u308c\u3070\uff0c\u305d\u306e\u571f\u306b\u751f\u606f\u3059\u308b\u751f\u7269\u6570\u304c\uff0c\u4e0e\u3048\u3089\u308c\u305f\u5806\u80a5\u306b\u542b\u307e\u308c\u3066\u3044\u308b\u751f\u7269\u6570\u306b\u304f\u3089\u3079\u3066\u5727\u5012\u7684\u306b\u591a\u304f\uff0c\u5806\u80a5\u306b\u571f\u306e\u751f\u7269\u306e\u7d66\u6e90\u3068\u3057\u3066\u306e\u76f4\u63a5\u7684\u306a\u52b9\u679c\u3092\u671f\u5f85\u3057\u306b\u304f\u3044\u3002\u3053\u306e\u52b9\u679c\u3082\u9020\u6210\u5730\u306e\u3088\u3046\u306a\u6975\u5ea6\u306b\u6709\u6a5f\u7269\u306e\u5c11\u306a\u3044\u571f\u304c\u4f5c\u571f\u3068\u306a\u3063\u305f\u5834\u5408\u306b\u9650\u5b9a\u3059\u3079\u304d\u3067\u3042\u308b\u3002
\u3000The effect of compost application on soil organisms is more likely to be cumulative than a one-year effect. However, even in this case, the direct effect of the diversification and increase in the number of organisms on crop growth may vary depending on other soil conditions.<\/p>\n\n\n\n
2. the less organic matter in the soil, the more effective compost is.<\/h3>\n\n\n\n
\u3000When we give compost to the soil nowadays, are we just giving it to the soil without any particular reason, just because it is for \"soil building\"? We need to think carefully about why we are giving compost to the soil and what effect we expect it to have. Depending on soil conditions, compost may or may not have the desired effect. As shown in Table 1, the criterion is whether the soil has more or less organic matter.
\u3000The amount of organic matter in the soil can only be determined by strictly analyzing it. To determine the amount of organic matter without analyzing the soil, look at the color of the soil. If the color of the soil is black to dark brown with a black tint, you can judge that there is a lot of organic matter in the soil.
\u3000Soils with low organic matter (light black color) can expect diverse effects from compost feeding. For soils with high organic matter (dark black color), we should expect mainly nutrient effects as a slow-release three-element fertilizer.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff12\u7ae0\u2212 \u5806\u80a5\u3068\u5316\u5b66\u80a5\u6599
\u7b2c13\u56de\u3000\u6709\u6a5f\u7269\u8cc7\u6750\u306e\u7a2e\u985e\u3068\u305d\u306e\u52b9\u679c
\u2212C\/N\u6bd4\u304c\u8981\u70b9\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u3000\uff17\u6708\u53f7 (\u7b2c742\u53f7)<\/p>\n\n\n\n
\u3000Compost was originally conceived as a material for transferring nutrients to farmland. In Japan, however, compost is now expected to be used as a stable organic matter and as a source of biological supply. Last month, we discussed the expected effects of such composts and how these expectations are reflected in crop production depending on the soil conditions.
\u3000This month, we will organize the expression of the effects of various organic materials, including compost, in terms of C\/N ratio. Furthermore, in Japan, compost used is often limited to \"fully matured compost. We will consider why this is so.<\/p>\n\n\n\n
1. C\/N ratio of organic materials and ease of decomposition<\/h3>\n\n\n\n
\u3000\u6709\u6a5f\u7269\u8cc7\u6750\u304c\u571f\u306b\u4e0e\u3048\u3089\u308c\u308b\u3068\uff0c\u571f\u306e\u5fae\u751f\u7269\u306b\u5206\u89e3\u3055\u308c\u3066\u3044\u304f\u3002\u3053\u306e\u6642\uff0c\u6709\u6a5f\u7269\u8cc7\u6750\u306e\u5206\u89e3\u3055\u308c\u3084\u3059\u3055\u306f\u70ad\u7d20\uff08C\uff09\u3068\u7a92\u7d20\uff08N\uff09\u306e\u6bd4\u7387\uff08C\/N\u6bd4\uff0c\u70ad\u7d20\u7387\u3068\u3082\u3044\u3046\uff09\u306b\u3088\u3063\u3066\u6c7a\u307e\u308b\u3002
\u3000\u70ad\u7d20\u304c\u5c11\u306a\u304f\u7a92\u7d20\u306e\u591a\u3044C\/N\u6bd4\u304c20\u304f\u3089\u3044\u3088\u308a\u5c0f\u3055\u3044\u6709\u6a5f\u7269\u8cc7\u6750\uff08\u8868\uff11\u53c2\u7167\uff0c\u30c0\u30a4\u30ba\u304b\u3059\uff0c\u9d8f\u3075\u3093\uff0c\u725b\u3075\u3093\u306a\u3069\uff09\u306f\uff0c\u571f\u306b\u6df7\u548c\u3055\u308c\u308b\u3068\u5fae\u751f\u7269\u306b\u65e9\u304f\u5206\u89e3\u3055\u308c\u308b\u3002\u3053\u306e\u305f\u3081\uff0c\u990a\u5206\u7684\u306a\u52b9\u679c\u304c\u73fe\u308c\u3084\u3059\u3044\u3002\u3064\u307e\u308a\uff0c\u990a\u5206\u6e90\u3068\u3057\u3066\u306e\u5229\u7528\u306b\u9069\u3057\u305f\u8cc7\u6750\u3067\u3042\u308b\u3002\u5b8c\u719f\u5806\u80a5\u3068\u3044\u308f\u308c\u308b\u306e\u306f\u3053\u306e\u3088\u3046\u306aC\/N\u6bd4\u3092\u6301\u3063\u3066\u3044\u308b\u3002\u3057\u304b\u3057\uff0c\u5206\u89e3\u3055\u308c\u3084\u3059\u3044\u306e\u3067\u571f\u306b\u6709\u6a5f\u7269\u3068\u3057\u3066\u6b8b\u308b\u306e\u306f\u308f\u305a\u304b\u3057\u304b\u306a\u3044\u3002\u305d\u308c\u3086\u3048\uff0c\u3053\u306e\u30bf\u30a4\u30d7\u306e\u6709\u6a5f\u7269\u8cc7\u6750\u306b\u306f\u571f\u306e\u4e2d\u3067\u5b89\u5b9a\u3057\u305f\u6709\u6a5f\u7269\u3068\u3057\u3066\u306e\u52b9\u679c\u306f\u671f\u5f85\u3057\u306b\u304f\u3044\u3002\u3053\u306e\u305f\u3081\uff0c\u571f\u306e\u7269\u7406\u7684\u306a\u6027\u8cea\u3092\u6539\u5584\u3059\u308b\u306b\u306f\u9069\u5f53\u306a\u8cc7\u6750\u3068\u306f\u3044\u3048\u306a\u3044\u3002
\u3000Conversely, organic materials with a C\/N ratio higher than about 30 (see Table 1), which are high in carbon and low in nitrogen (e.g., bark compost, inawara, wheat straw, etc.), decompose slowly in the soil. For this reason, they are not expected to be very effective as nutrients. However, organic materials accumulate in the soil as relatively stable organic matter. Therefore, these materials should be used when the objective is to improve the physical properties of the soil.
\u3000Specific examples of each type of organic material and their main uses are listed in Table 1.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-20.png\")
<\/figure><\/div>\n\n\n2. use organic materials with high C\/N ratio with caution<\/h3>\n\n\n\n
\u3000When organic materials with a C\/N ratio of 30 or higher are used, even if the purpose of their use is to improve the physical properties of the soil, they may have a negative effect on crops. After a short time of feeding this type of organic material, the crop may show symptoms of nitrogen deficiency, such as yellowish-green leaf color and growth suppression. This phenomenon is called \"nitrogen starvation. This is a strange phenomenon in which crops become nitrogen-deficient despite the application of fertilizer. The mechanism by which nitrogen starvation occurs is interesting.
\u3000C\/N\u6bd4\u306e\u5927\u304d\u3044\u6709\u6a5f\u7269\u8cc7\u6750\u304c\u571f\u306b\u4e0e\u3048\u3089\u308c\uff0c\u305d\u308c\u304c\u5fae\u751f\u7269\u306b\u5206\u89e3\u3055\u308c\u3066\u3044\u304f\u3068\u304d\uff0c\u5fae\u751f\u7269\u306b\u3068\u3063\u3066\u30a8\u30cd\u30eb\u30ae\u30fc\u6e90\u3068\u306a\u308b\u70ad\u7d20\uff08C\uff09\u306f\u6709\u6a5f\u7269\u8cc7\u6750\u304b\u3089\u5341\u5206\u306b\u4f9b\u7d66\u3055\u308c\u308b\u3002\u3053\u308c\u306b\u5bfe\u3057\uff0c\u5fae\u751f\u7269\u306b\u3068\u3063\u3066\u91cd\u8981\u306a\u30bf\u30f3\u30d1\u30af\u8cea\u306e\u6804\u990a\u6e90\u3067\u3042\u308b\u7a92\u7d20\uff08N\uff09\u306e\u4f9b\u7d66\u91cf\u306f\uff0c\u70ad\u7d20\u306b\u6bd4\u3079\u76f8\u5bfe\u7684\u306b\u5c11\u306a\u3044\u3002\u3053\u306e\u305f\u3081\uff0c\u3053\u306e\u8cc7\u6750\u3067\u306f\u5fae\u751f\u7269\u306e\u7a92\u7d20\u8981\u6c42\u3092\u6e80\u305f\u3059\u3053\u3068\u304c\u3067\u304d\u306a\u3044\u3002\u305d\u3053\u3067\uff0c\u7a92\u7d20\u3092\u5fc5\u8981\u3068\u3059\u308b\u5fae\u751f\u7269\u306f\uff0c\u571f\u306e\u4e2d\u306b\u3082\u3068\u3082\u3068\u3042\u308b\u7121\u6a5f\u614b\u7a92\u7d20\uff08\u785d\u9178\u614b\u7a92\u7d20\u3084\u30a2\u30f3\u30e2\u30cb\u30a2\u614b\u7a92\u7d20\uff09\u3084\uff0c\u80a5\u6599\u3068\u3057\u3066\u4e0e\u3048\u3089\u308c\u305f\u7121\u6a5f\u614b\u7a92\u7d20\u3092\u6804\u990a\u6e90\u3068\u3057\u3066\u4f53\u5185\u306b\u53d6\u308a\u8fbc\u307f\uff0c\u81ea\u8eab\u306e\u30bf\u30f3\u30d1\u30af\u8cea\u306a\u3069\u306e\u6709\u6a5f\u614b\u7a92\u7d20\u306b\u5f62\u614b\u3092\u5909\u5316\u3055\u305b\u308b\uff08\u3053\u308c\u3092\u7121\u6a5f\u614b\u7a92\u7d20\u306e\u6709\u6a5f\u5316\u3068\u3044\u3046) \u3002\u7d50\u679c\u7684\u306b\uff0c\u571f\u306e\u4e2d\u306b\u3042\u3063\u305f\u7121\u6a5f\u614b\u7a92\u7d20\u304c\u4f5c\u7269\u306b\u5229\u7528\u3057\u306b\u304f\u3044\u5f62\u614b\u306b\u5909\u5316\u3059\u308b\u306e\u3067\uff0c\u4f5c\u7269\u306b\u7a92\u7d20\u6b20\u4e4f\u75c7\u304c\u73fe\u308c\u308b\u3002<\/p>\n\n\n\n
3. Why is the supremacy of mature compost in our country?<\/h3>\n\n\n\n
\u3000As mentioned in the 11th issue of this series (May issue), in Europe, compost is traditionally regarded as a nutrient transfer material. Keeping livestock is a prerequisite for compost production, and compost is regarded as a source of nutrients itself. Therefore, as in Japan, compost is not expected to have a variety of effects, including effects as a stable organic matter and as a source of biological resources, in addition to its effect as a source of nutrients.
\u3000On the other hand, before the advent of chemical fertilizers, compost had to be used as a source of nutrients in Japan. In Japanese agriculture, however, livestock were used mainly for labor, not for compost production. Farmers kept only a small number of livestock, and there was not much livestock manure available for compost production. Most of the raw materials for composting were ina straw, wheat straw, and fallen leaves and branches from nearby satoyama, and their C\/N ratios were as high as over 60. If the C\/N ratio remained high, the crops would be at risk of nitrogen starvation.<\/p>\n\n\n\n
\u3000\u8150\u719f\u3055\u305b\u308b\u904e\u7a0b\u3067\uff0c\u542b\u307e\u308c\u3066\u3044\u305f\u70ad\u7d20\u306f\uff0c\u9178\u7d20\u304c\u5341\u5206\u3042\u308b\u6761\u4ef6\uff08\u597d\u6c17\u7684\u6761\u4ef6\uff09\u3067\u5fae\u751f\u7269\u306b\u3088\u3063\u3066\u5206\u89e3\u3055\u308c\uff0c\u6700\u7d42\u7684\u306b\u4e8c\u9178\u5316\u70ad\u7d20\uff08CO2<\/sub>\uff09\u306b\u5909\u5316\u3057\u3066\u5927\u6c17\u4e2d\u306b\u653e\u51fa\u3055\u308c\u308b\u3002\u3053\u308c\u306b\u3088\u3063\u3066\u539f\u6599\u306b\u542b\u307e\u308c\u3066\u3044\u305f\u70ad\u7d20\u91cf\u304c\u5c11\u306a\u304f\u306a\u308b\u3002\u4e00\u65b9\u306e\u7a92\u7d20\u306f\uff0c\u305d\u306e\u591a\u304f\u306f\u8150\u719f\u5316\u304c\u9032\u3093\u3067\u3082\u539f\u6599\u306b\u6e29\u5b58\u3055\u308c\u308b\u3002\u3053\u306e\u305f\u3081\uff0c\u8150\u719f\u5316\u3092\u3059\u3059\u3081\u3066\u3082\u7a92\u7d20\uff08N\uff09\u91cf\u306f\u5927\u304d\u304f\u5909\u5316\u305b\u305a\uff0c\u70ad\u7d20\uff08C\uff09\u91cf\u304c\u6e1b\u5c11\u3059\u308b\u305f\u3081C\/N\u6bd4\u304c\u5c0f\u3055\u304f\u306a\u308b\u3002\u5b8c\u719f\u5806\u80a5\u3068\u306f\uff0c\u8150\u719f\u5316\u3067C\/N\u6bd4\u3092\u5c0f\u3055\u304f\u3055\u305b\u305f\u5806\u80a5\u306e\u3053\u3068\u3067\u3042\u308b\u3002
\u3000C\/N\u6bd4\u306e\u5c0f\u3055\u3044\u5b8c\u719f\u5806\u80a5\u304c\u571f\u306b\u4e0e\u3048\u3089\u308c\u308b\u3068\uff0c\u5fae\u751f\u7269\u306b\u3088\u308b\u5206\u89e3\u304c\u65e9\u304f\u9032\u3080\u3002\u5206\u89e3\u3068\u3068\u3082\u306b\uff0c\u3053\u306e\u5806\u80a5\u306b\u542b\u307e\u308c\u308b\u7a92\u7d20\u306f\u4f5c\u7269\u304c\u5438\u53ce\u3057\u306b\u304f\u3044\u6709\u6a5f\u614b\u304b\u3089\u5438\u53ce\u3057\u3084\u3059\u3044\u7121\u6a5f\u614b\u306e\u30a2\u30f3\u30e2\u30cb\u30a2\u614b\u7a92\u7d20\u306b\u5909\u5316\u3059\u308b\u3002\u305d\u3057\u3066\uff0c\u3053\u308c\u304c\u990a\u5206\u3068\u3057\u3066\u4f5c\u7269\u306b\u5438\u53ce\u3055\u308c\u308b\u3002\u3064\u307e\u308a\uff0c\u30a4\u30ca\u30ef\u30e9\u3084\u30e0\u30ae\u30ef\u30e9\u3068\u3044\u3063\u305fC\/N\u6bd4\u304c\u5927\u304d\u3044\u6709\u6a5f\u7269\u8cc7\u6750\u306f\uff0c\u5341\u5206\u306b\u8150\u719f\u3055\u305b\u3066\u5b8c\u719f\u5806\u80a5\u307e\u3067\u5206\u89e3\u3055\u305b\u306a\u3044\u3068\uff0c\u571f\u306b\u4e0e\u3048\u3066\u3082\u990a\u5206\u3068\u3057\u3066\u306e\u52b9\u679c\u304c\u73fe\u308c\u306b\u304f\u3044\u3002\u5316\u5b66\u80a5\u6599\u306e\u306a\u3044\u6642\u4ee3\uff0c\u308f\u304c\u56fd\u3067\u3082\u5806\u80a5\u306f\u8cb4\u91cd\u306a\u990a\u5206\u6e90\u3060\u3063\u305f\u3002\u990a\u5206\u6e90\u3068\u3057\u3066\u5229\u7528\u3057\u3088\u3046\u3068\u3059\u308b\u304b\u304e\u308a\uff0cC\/N\u6bd4\u3092\u5c0f\u3055\u304f\u3057\u3066\u304a\u304f\u306e\u304c\u5fc5\u9808\u6761\u4ef6\u3060\u3063\u305f\u3002\u308f\u304c\u56fd\u3067\u300c\u5806\u80a5\u3092\u4f7f\u3046\u306a\u3089\uff0c\u5b8c\u719f\u5806\u80a5\u3067\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u300d\u3068\u3044\u3046\u5b8c\u719f\u5806\u80a5\u81f3\u4e0a\u4e3b\u7fa9\u304c\u5f37\u8abf\u3055\u308c\u308b\u306e\u306f\uff0c\u4e0a\u306b\u8ff0\u3079\u305f\u3088\u3046\u306a\u4f1d\u7d71\u304c\u73fe\u5728\u307e\u3067\u53d7\u3051\u7d99\u304c\u308c\u305f\u7d50\u679c\u3060\u308d\u3046\u3002<\/p>\n\n\n\nCurrent compost is treated as industrial waste<\/h3>\n\n\n\n
\u3000In Japan, the value of compost as a source of nutrients has declined since the introduction of chemical fertilizers as a nutrient transfer material. Labor-intensive compost production is no longer done, and compost is used less and less. Rice farmers, in particular, began to avoid applying compost to their rice paddies. This is because composted manure releases large amounts of nitrogen after the summer, resulting in high-protein rice and a significant decrease in eating quality.
\u3000Livestock farmers often run multi-cattle operations relying on imported concentrate feed for livestock feed. Livestock farmers often keep a large number of animals and depend on imported concentrated feed for livestock feed. The compost produced by livestock farms is treated as industrial waste and is not used effectively. In Japan, it is doubtful whether compost is being used properly, despite the importance of \"compost for soil preparation.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff12\u7ae0\u2212 \u5806\u80a5\u3068\u5316\u5b66\u80a5\u6599
\u7b2c14\u56de\u3000\u990a\u5206\u6e90\u304c\u5806\u80a5\u304b\u3089\u5316\u5b66\u80a5\u6599\u3078\u5909\u5316\u3059\u308b\u6642\u4ee3
\u2212\u305d\u306e\u6b74\u53f2\u7684\u7d4c\u7def\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74 8\/9\u6708\u5408\u4f75\u53f7 (\u7b2c743\u53f7)<\/p>\n\n\n\n
\u3000The significant effect of compost on crop production can be traced back as far as the time of Aristotle. It was not until the Norfolk farming in the 19th century that compost was actively used to transfer nutrients to farmland and to increase food production (see the May issue of this year's Newsletter). This month's story is about the shift from compost to chemical fertilizers as a source of nutrients. The trigger was the agricultural depression. What was the background?<\/p>\n\n\n\n
1. what the Flemish saying teaches<\/h3>\n\n\n\n
\u3000\u30ce\u30fc\u30d5\u30a9\u30fc\u30af\u8fb2\u6cd5\u306f\uff0c\u990a\u5206\u5faa\u74b0\u304b\u3089\u305f\u3069\u308a\u3064\u3044\u305f\uff14\u5e74\u8f2a\u4f5c\uff08\u30b3\u30e0\u30ae\u2212\u98fc\u6599\u7528\u30ab\u30d6\u2212\u30aa\u30aa\u30e0\u30ae\u2212\u30a2\u30ab\u30af\u30ed\u30fc\u30d0\uff09\u306e\u8fb2\u6cd5\u3067\u3042\u3063\u305f\uff08\u56f3\uff11) \u3002\u5bb6\u755c\u306e\u30a8\u30b5\u3068\u306a\u308b\u98fc\u6599\u4f5c\u7269\uff08\u98fc\u6599\u7528\u30ab\u30d6\u3084\u30a2\u30ab\u30af\u30ed\u30fc\u30d0\uff09\u306b\u571f\u306e\u4e2d\u306b\u3042\u308b\u990a\u5206\u3092\u5438\u53ce\u3055\u305b\uff0c\u305d\u306e\u30a8\u30b5\u3092\u5bb6\u755c\u306b\u4e0e\u3048\u3066\uff0c\u305d\u306e\u5bb6\u755c\u304b\u3089\u3075\u3093\u5c3f\u3068\u3044\u3046\u5f62\u614b\u3067\u990a\u5206\u3092\u56de\u53ce\u3057\uff0c\u6700\u7d42\u7684\u306b\u305d\u308c\u3092\u5806\u80a5\u306b\u3057\u3066\u4eba\u306e\u98df\u6599\u751f\u7523\u306e\u7551\u3078\u79fb\u8ee2\u3055\u305b\u308b\u3068\u3044\u3046\u5faa\u74b0\u578b\u8fb2\u696d\u3067\u3042\u308b\u3002\u3053\u308c\u306f\uff0c\u30a4\u30ae\u30ea\u30b9\u30fb\u30ce\u30fc\u30d5\u30a9\u30fc\u30af\u306e\u5bfe\u5cb8\uff0c\u30e8\u30fc\u30ed\u30c3\u30d1\u672c\u571f\u306e\u30d5\u30e9\u30f3\u30c9\u30eb\u5730\u65b9\uff08\u73fe\u5728\u306e\u30aa\u30e9\u30f3\u30c0\u5357\u90e8\u304b\u3089\u30d9\u30eb\u30ae\u30fc\u897f\u90e8\uff0c\u30d5\u30e9\u30f3\u30b9\u5317\u90e8\u5730\u57df\uff09\u306b\u53e4\u304f\u304b\u3089\u4f1d\u308f\u308b\u300c\u98fc\u6599\u306a\u3051\u308c\u3070\u5bb6\u755c\u306a\u3057\uff0c\u5bb6\u755c\u306a\u3051\u308c\u3070\u80a5\u6599\u306a\u3057\uff0c\u80a5\u6599\u306a\u3051\u308c\u3070\u53ce\u7a6b\u306a\u3057\u300d\u3068\u306e\u683c\u8a00\u305d\u306e\u3082\u306e\u3060\u3063\u305f\u3002\u30e8\u30fc\u30ed\u30c3\u30d1\u306e\u8f2a\u4f5c\u3067\uff0c\u4f5c\u7269\u751f\u7523\u3092\u7dad\u6301\u3059\u308b\u305f\u3081\u306e\u990a\u5206\u79fb\u8ee2\u8cc7\u6750\uff08\u80a5\u6599\uff09\u3068\u3057\u3066\u5806\u80a5\u304c\u5927\u304d\u306a\u5f79\u5272\u3092\u306f\u305f\u3057\u3066\u3044\u308b\u3053\u3068\u3092\uff0c\u3053\u306e\u683c\u8a00\u306f\u96c4\u5f01\u306b\u8a9e\u3063\u3066\u3044\u308b\u3002<\/p>\n\n\n\n
\u3000However, there is another point in this saying that should not be overlooked. The compost is a source of fertilizer, but it is also a source of fodder for livestock. As the Flemish proverb points out, compost cannot be produced as a source of nutrients without producing crops that feed livestock (forage crops) rather than food for people. That is why Norfolk Farming allocates half of the land area on the farm to fodder crop production and adds fodder turnips and red clover to the crop rotation. This has not only increased the number of livestock that can be raised, but also made it possible to keep the livestock in the barns through the winter. As a result, the recovery rate of livestock manure has increased, and the production of manure as a source of nutrients has increased. This has made it possible to increase the amount of manure applied to fields that produce food for people. This has allowed the yield levels of wheat and barley to nearly double at a stroke.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-21.png\")
<\/figure><\/div>\n\n\n2. alternative sources of compost nutrients needed to escape agricultural depression<\/h3>\n\n\n\n
\u3000Until the use of chemical fertilizers became commonplace, this method of farming became widely popular because of its revolutionary high yields. In the 19th century, British agriculture entered a golden age at the height of Norfolk farming. However, this golden age did not last long. The Cereal Laws, which had previously restricted grain imports, were repealed, and inexpensive wheat was imported in large quantities from the United States and Canada. This caused a major blow to wheat cultivation in the U.K. and led to an agricultural depression. This depression began around 1875 and continued for about 60 years, although it was temporarily interrupted during World War I (McLean, 1991).
\u3000The agricultural depression was severe in the Norfolk region as well. In Norfolk farming, fodder turnips and red clover plots, which are grown to feed livestock, generate no direct income. They are grown for manure production as a source of nutrients. In order to get out of the recession, farmers have been tempted to stop the unprofitable forage production and grow cash crops to feed people. This would increase their profits. However, there was a problem. If they stopped producing fodder, they would no longer be able to feed their livestock, which would also mean that they would no longer be able to produce compost, and crop production itself would decline. Therefore, the important thing was to find a source of nutrients that could be substituted for compost. This is where chemical fertilizers, which were beginning to be sold and distributed at the time, came into the spotlight.<\/p>\n\n\n\n
3. results of agricultural experiment stations established with farmers' investment<\/h3>\n\n\n\n
\u5e02\u8ca9\u5316\u5b66\u80a5\u6599\u3068\u3057\u3066\u904e\u30ea\u30f3\u9178\u77f3\u7070\u304c\u4e16\u754c\u3067\u521d\u3081\u3066\u767b\u5834\u3057\u305f\u306e\u306f1843\u5e747\u67081\u65e5\u3002\u8fb2\u696d\u4e0d\u6cc1\u304c\u59cb\u307e\u308b\u5c11\u3057\u524d\u306e\u3053\u3068\u3060\u3063\u305f\u3002\u3082\u3061\u308d\u3093\uff0c\u5316\u5b66\u80a5\u6599\u304c\u4e00\u822c\u306e\u8fb2\u5bb6\u306b\u5e83\u304f\u4f7f\u308f\u308c\u308b\u3068\u3044\u3046\u72b6\u6cc1\u3067\u306f\u306a\u3044\u3002\u5316\u5b66\u80a5\u6599\u306e\u666e\u53ca\u306b\u306f\u307e\u3060\u307e\u3060\u6642\u9593\u304c\u5fc5\u8981\u3060\u3063\u305f\u3002\u4f7f\u7528\u7d4c\u9a13\u306e\u306a\u3044\u5316\u5b66\u80a5\u6599\u304c\uff0c\u672c\u5f53\u306b\u5806\u80a5\u306e\u4ee3\u66ff\u990a\u5206\u6e90\u3068\u306a\u308b\u306e\u304b\u3069\u3046\u304b\uff0c\u8ab0\u3082\u304c\u4e0d\u5b89\u3060\u3063\u305f\u3002\u305d\u308c\u3092\u89e3\u6d88\u3059\u308b\u306b\u306f\u79d1\u5b66\u7684\u88cf\u4ed8\u3051\u304c\u6b32\u3057\u304b\u3063\u305f\u3002\u305d\u3053\u3067\uff0c\u30ce\u30fc\u30d5\u30a9\u30fc\u30af\u306e\u8fb2\u5bb6\u306f\u81ea\u3089\u51fa\u8cc7\u3057\u3066\u30ce\u30fc\u30d5\u30a9\u30fc\u30af\u8fb2\u696d\u8a66\u9a13\u5834\uff08\u5f8c\u306b\u30e2\u30fc\u30ec\u30a4\u7814\u7a76\u30bb\u30f3\u30bf\u30fc\u306e\u6642\u4ee3\u3092\u7d4c\u3066\uff0c\u73feThe Morley Agricultural Foundation\u306b\u7d99\u627f\uff09\u30921908\u5e74\u306b\u8a2d\u7acb\u3057\u305f\uff08\u56f3\uff12) \u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-22.png\")
<\/figure><\/div>\n\n\n\u3000Results of a 12-year long-term crop rotation trial at the Norfolk Agricultural Experiment Station showed that when crop residues (e.g., wheat straw and sugar beet tops) are incorporated into the soil with chemical fertilizers, wheat and barley seedling yields can be maintained at the same level as in composted treatments, even without the application of compost ( Raynsand Culpin, 1948). Based on these results, it was recommended that sugar beets be grown instead of turnips for forage and that balayasho be grown instead of red clover (McLean, 1991), provided that chemical fertilizers were used in combination. Thus, concerns about chemical fertilizers were gradually resolved, and the source of nutrients for Norfolk farming gradually shifted from compost to chemical fertilizers, leading to the acceptance of chemical fertilizers in the world.<\/p>\n\n\n\n
4. dilemma associated with compost production in recycling-oriented agriculture<\/h3>\n\n\n\n
\u3000The main reason for the introduction of chemical fertilizers into Norfolk farming was the need for land to produce fodder for livestock, which is the key to the nutrient cycle. The agricultural depression made it impossible to allocate that land for feed production. Moreover, as crop yields increase, the amount of nutrients taken out of the field also increases. This requires a large amount of compost as a source of nutrients to replenish the crop. Increased production of manure requires an increase in the number of livestock, as well as more farmland for the production of feed for the increased number of livestock. However, the profitability of that farmland is low. This is the dilemma that arises when trying to rely solely on compost as a source of nutrients in recycling-oriented agriculture.
\u3000More importantly, as Liebig, who with Sprengel argued that plant nutrients are inorganic, once criticized, there can be no perfect cycle in any cyclical agriculture. The produce is taken off the farm to be sold. The nutrients absorbed by the farmland are surely taken out of the circulation path. Unless the nutrients are brought in from outside the circulation path, the nutrients contained in the farmland in the circulation path are gradually depleted. Liebig called this plunder agriculture and recommended the use of chemical fertilizers to replenish nutrients.<\/p>\n\n\n\n
5. another test to confirm fertilizer efficacy of chemical fertilizers<\/h3>\n\n\n\n
\u3000It was Rose of England who first introduced chemical fertilizers to the world. Rose was also concerned about whether chemical fertilizers were really as effective as compost. He therefore founded the Rothamsted Agricultural Experiment Station on his own to test the efficacy of fertilizers. This was 65 years before the Norfolk Agricultural Experiment Station, the oldest agricultural experiment station in the world. The testing began in 1843, the year chemical fertilizers were first sold. These tests have continued to the present day, some 180 years later. We will discuss the results in next month's issue.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff12\u7ae0\u2212 \u5806\u80a5\u3068\u5316\u5b66\u80a5\u6599
\u7b2c15\u56de\u3000\u5316\u5b66\u80a5\u6599\u3060\u3051\u3057\u304b\u4f7f\u308f\u306a\u3044\u7551\u306e\u30b3\u30e0\u30ae\u306e\u751f\u80b2
\u2212\u5806\u80a5\u3060\u3051\u306e\u7551\u3068\u6bd4\u3079\u308b\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u300010\u6708\u53f7 (\u7b2c744\u53f7)<\/p>\n\n\n\n
\u3000\u5316\u5b66\u80a5\u6599\u3092\u4e16\u754c\u3067\u6700\u521d\u306b\u5e02\u8ca9\u3057\u305f\u306e\u306f\uff0c\u30a4\u30ae\u30ea\u30b9\u306e\u30ed\u30fc\u30ba\u3060\u3063\u305f\u30021843\u5e747\u67081\u65e5\u306e\u3053\u3068\u3067\u3042\u308b\u3002\u305d\u308c\u307e\u3067\u306e\u4f5c\u7269\u306e\u990a\u5206\u6e90\u306f\u3082\u3063\u3071\u3089\u5806\u80a5\u3067\u3042\u3063\u305f\u3002\u30c9\u30a4\u30c4\u306e\u30c6\u30fc\u30e4\u304c\u6307\u6458\u3057\u305f\u690d\u7269\u306e\u990a\u5206\u306f\u571f\u306b\u3042\u308b\u6709\u6a5f\u7269\uff08\u30d5\u30e0\u30b9\uff1d\u8150\u690d\uff09\u3067\u3042\u308b\u3068\u3044\u3046\u306e\u304c\u901a\u8aac\u306e\u6642\u4ee3\u3060\u3063\u305f\u304b\u3089\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
1. an era in which plant nutrients are changing from organic to inorganic<\/h3>\n\n\n\n
\u3000In 1828, Sprengel of Germany was the first to question this common theory and point out that plant nutrients are not organic but inorganic (minerals). It was Liebig, also of Germany, who further supported his point of view and popularized the theory in 1840. It was during this period that Rose marketed an inorganic chemical fertilizer (a patented fertilizer composed of lime superphosphate, ammonium phosphate, and potassium silicate) as a nutrient for crops.
\u3000Rose attempted several trials in his hometown of Rothamsted, Harpenden, to verify the efficacy of the chemical fertilizers he intended to sell. He conducted pot trials in 1837-39 and small field trials in 1840-41. From these trials, he recognized the importance of phosphorus as a nutrient for cabbage, since the highest yields were obtained when cabbage was treated with ammonium phosphate, which contained phosphorus as well as nitrogen.<\/p>\n\n\n\n
2. overview of broadbore wheat field trials<\/h3>\n\n\n\n
\u3000Rose brought in Gilbert, who had studied chemistry at Liebig's, as a scientific collaborator and began comparing the nutrient effects of chemical fertilizers and compost. It was in the fall of 1843, the very same year that chemical fertilizers were introduced to the world, that he sowed wheat (fall-sown wheat) as a crop for testing. This is the Broadbark wheat test plot introduced this month. The year 1843 was the founding year of the Rothamsted Agricultural Experiment Station.
\u3000This field trial has continued uninterruptedly since then until now, 179 years later. In addition to the no-fertilizer treatment, the chemical fertilizer-treated area was given a certain amount of phosphorus, potassium, magnesium, and other nutrients in addition to nitrogen at four levels: 0, 48, 96, and 144 kg\/ha of nitrogen. Currently, in addition to these four levels, trials are continuing at seven levels, including treatments of 192, 240, and 288 kg\/ha. Of course, since the trials were started in the same year that chemical fertilizers were introduced to the market, there is no field on earth that has been grown with chemical fertilizers alone for a longer period of time than the Broadbork field.
\u30001968\u5e74\u306b\u306f\uff0c\u8a66\u9a13\u306b\u7528\u3044\u308b\u30b3\u30e0\u30ae\u306e\u54c1\u7a2e\u3092\u9ad8\u53ce\u91cf\u54c1\u7a2e\uff08\u7a08\u9577\u3092\u77ed\u304f\u3057\u3066\u591a\u80a5\u6761\u4ef6\u3067\u3082\u5012\u4f0f\u3057\u306b\u304f\u304f\u3057\uff0c\u8449\u3092\u76f4\u7acb\u306b\u3057\u3066\u53d7\u5149\u614b\u52e2\u3092\u6539\u826f\u3057\u305f\u54c1\u7a2e\uff09\u306b\u5909\u66f4\u3057\u3066\u3044\u308b\u3002\u540c\u30581968\u5e74\u304b\u3089\u305d\u308c\u307e\u3067\u306e\u9023\u4f5c\u51e6\u7406\u306e\u4ed6\u306b\uff15\u5e74\u8f2a\u4f5c\u306e\u51e6\u7406\u3092\u52a0\u3048\uff0c\u5806\u80a535t\/ha\u306b\u7a92\u7d20\u309296kg\/ha\uff082005\u5e74\u304b\u3089\u306f144kg\/ha\u306b\u5897\u91cf\uff09\u8ffd\u52a0\u3059\u308b\u51e6\u7406\u3082\u304a\u3053\u306a\u3046\u3088\u3046\u306b\u306a\u3063\u305f\u3002<\/p>\n\n\n\n
3. results of broadbark wheat field trials<\/h3>\n\n\n\n\uff11\uff09\u9069\u91cf\u306e\u5316\u5b66\u80a5\u6599\u3067\u5806\u80a5\u533a\u3068\u540c\u7b49\u306e\u53ce\u91cf<\/h4>\n\n\n\n
\u3000Figure 1 shows the results of this trial. The yield of wheat seedlings in the chemical fertilizer (N144 kg\/ha) area of the continuous wheat test was not much different from that in the compost area. It was confirmed that the production of wheat seedlings with chemical fertilizer alone was almost equal to that with 35 t\/ha of compost, if the amount of fertilizer applied was appropriate.
\u3000Interestingly, after 60 years of continuous cropping, in 1902, both treatments showed continuous crop failure and yield decreased. When the fallow treatment was introduced (one-year fallow followed by four-year row cropping), yields recovered again. This indicates that the continuous cropping failure of wheat occurs not only in the chemical fertilizer area but also in the compost area, and that the fallow treatment is more effective for recovery than the nutrient treatments such as compost or chemical fertilizer.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-23.png\")
<\/figure><\/div>\n\n\n(2) Dramatic increase in yields with the introduction of high-yielding varieties<\/h4>\n\n\n\n
\u3000Since 1968, when high-yielding varieties were introduced, the yield of row crops of wheat has nearly doubled, despite no change in compost or chemical fertilizer application treatments. This confirms the high seed production capacity of high-yielding varieties.
\u3000Furthermore, in the five-year crop rotation established after 1968, when the nitrogen content of chemical fertilizers was added to the compost to increase the total nitrogen application, the yield was nearly 10 t\/ha. This is not only about three times the yield of the composted area in the old variety era until 1967, but also about twice the average yield in Japan. The effect of the addition of chemical fertilizer nutrients to the compost is clear, and the high-yielding variety's response to fertilizer nutrients is understandable.<\/p>\n\n\n\n
3) Soil organisms in fields where only chemical fertilizers are used.<\/h4>\n\n\n\n
\u3000\u5316\u5b66\u80a5\u6599\u3092\u4f7f\u3044\u3064\u3065\u3051\u308b\u3068\u571f\u306e\u4e2d\u306e\u751f\u7269\u304c\u6b7b\u306b\u7d76\u3048\uff0c\uff62\u571f\u304c\u6b7b\u306c\u300d\u3068\u5fc3\u914d\u3059\u308b\u4eba\u304c\u3044\u308b\u3002\u3082\u3057\uff0c\u5316\u5b66\u80a5\u6599\u3092\u4f7f\u3044\u7d9a\u3051\u308b\u3053\u3068\u3067\u571f\u306e\u751f\u7269\u304c\u7d76\u6ec5\u3059\u308b\u306e\u3067\u3042\u308c\u3070\uff0c\u3082\u3061\u308d\u3093\uff0c\u3053\u306e\u8a66\u9a13\u306e\u30b3\u30e0\u30ae\u306e\u53ce\u91cf\u3084\u751f\u80b2\u306b\u5f71\u97ff\u3059\u308b\u306f\u305a\u3067\u3042\u308b\u3002\u3057\u304b\u3057\uff0c\u305d\u306e\u3088\u3046\u306a\u73fe\u8c61\u306f\uff0c\u4e16\u754c\u3067\u6700\u3082\u9577\u304f\u5316\u5b66\u80a5\u6599\u3060\u3051\u3092\u4f7f\u3044\u7d9a\u3051\u305f\uff0c\u3053\u306e\u30d6\u30ed\u30fc\u30c9\u30dc\u30fc\u30af\u30fb\u30b3\u30e0\u30ae\u8a66\u9a13\u5703\u5834\u3067\u3055\u3048\uff0c\u307e\u3063\u305f\u304f\u8a8d\u3081\u3089\u308c\u3066\u3044\u306a\u3044\uff08\u56f3\uff11) \u3002\u5316\u5b66\u80a5\u6599\u533a\u3068\u5806\u80a5\u533a\u306e\u571f\u306e\u751f\u7269\u6570\u3092\u8abf\u67fb\u3057\u305f\u7d50\u679c\u306b\u3088\u308b\u3068\uff0c\u5316\u5b66\u80a5\u6599\u3060\u3051\u3092\u65bd\u4e0e\u3057\u7d9a\u3051\u305f\u305f\u3081\u306b\uff0c\u571f\u306e\u751f\u7269\u304c\u751f\u606f\u3057\u306a\u304f\u306a\u3063\u305f\u3068\u3044\u3046\u4e8b\u5b9f\u306f\u306a\u3044\uff08\u8868\uff11) \u3002
\u3000Russell, who was the head of the Rothamsted Farm Experiment Station for many years, clearly pointed out that \"there is some concern that chemical fertilizers are harmful to earthworms and should not be used. However, Russell clearly pointed out that \"there is no indication that this is the case in the Broadbark wheat test plots after more than 100 years of continuous application of chemical fertilizers in amounts greater than customary\" (Russell, 1957).
\u3000These test results indicate that, as long as chemical fertilizers are used appropriately, there is no need to worry about their negative effects on crops.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-24.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff12\u7ae0\u2212 \u5806\u80a5\u3068\u5316\u5b66\u80a5\u6599
\u7b2c16\u56de\u3000\u5806\u80a5\u3068\u5316\u5b66\u80a5\u6599\uff0c\u305d\u306e\u52b9\u679c\u3092\u6bd4\u3079\u308b
\u2212\u5171\u901a\u70b9\u3068\u3061\u304c\u3044\u306f\u4f55\u304b\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u300011\u6708\u53f7 (\u7b2c745\u53f7)<\/p>\n\n\n\n
\u3000From the 11th (May) to the 13th (July) issue of this series, we have discussed compost, and in the 14th (August\/September) and 15th (October) issues, we have discussed chemical fertilizers. We have described under what circumstances compost and chemical fertilizers were introduced to the world and what effects they have on crop production. In this month's issue, we will review the past, compare the effects of compost and chemical fertilizers, and summarize the similarities and differences between them. In the following, the term \"compost\" simply refers to organic materials, including both fully matured and immature compost.<\/p>\n\n\n\n
1. effects of diverse composts<\/h3>\n\n\n\n
\u3000\u3059\u3067\u306b\u7b2c12\u56de\u3067\u8a73\u3057\u304f\u8ff0\u3079\u305f\u3088\u3046\u306b\uff0c\u5806\u80a5\u3092\u8fb2\u5730\u306b\u4e0e\u3048\u305f\u5834\u5408\uff0c\u5927\u304d\u304f\u5206\u3051\u3066\uff13\u3064\u306e\u52b9\u679c\u304c\u3042\u308b\u3002\u3059\u306a\u308f\u3061\uff0c\u2460\u990a\u5206\u3068\u3057\u3066\u306e\u52b9\u679c\uff0c\u2461\u6bd4\u8f03\u7684\u5206\u89e3\u3055\u308c\u306b\u304f\u3044\u5b89\u5b9a\u3057\u305f\u6709\u6a5f\u7269\u3068\u3057\u3066\u306e\u52b9\u679c\uff0c\u2462\u751f\u7269\u306e\u4f9b\u7d66\u6e90\u3068\u3057\u3066\u306e\u52b9\u679c\u3067\u3042\u308b\u3002\u305f\u3060\u3057\uff0c\u3053\u308c\u3089\u306e\u52b9\u679c\u306f\uff0c\u3042\u304f\u307e\u3067\u3082\u3053\u3046\u3057\u305f\u52b9\u679c\u304c\u671f\u5f85\u3055\u308c\u308b\u3068\u3044\u3046\u3053\u3068\u3067\u3042\u3063\u3066\uff0c\u5806\u80a5\u3092\u571f\u306b\u4e0e\u3048\u308c\u3070\u5fc5\u305a\u81ea\u52d5\u7684\u306b\u767a\u73fe\u3059\u308b\u3068\u3044\u3046\u3053\u3068\u3067\u306f\u306a\u3044\u3002\u307e\u305f\uff0c\u2462\u751f\u7269\u306e\u4f9b\u7d66\u6e90\u3068\u3057\u3066\u306e\u52b9\u679c\u306f\uff0c\u65b0\u898f\u306b\u9020\u6210\u3055\u308c\u305f\u8fb2\u5730\u306e\u3088\u3046\u306a\u683d\u57f9\u5c65\u6b74\u304c\u306a\u3044\u3068\u3053\u308d\u3067\u767a\u73fe\u3059\u308b\u52b9\u679c\u3067\u3042\u308a\uff0c\u683d\u57f9\u6b74\u306e\u3042\u308b\u8fb2\u5730\u3067\u306f\u305d\u306e\u52b9\u679c\u306b\u5927\u304d\u306a\u671f\u5f85\u306f\u3067\u304d\u306a\u3044\u3002
\u3000Furthermore, the effects of (1) and (2) may or may not be expected depending on soil conditions (organic matter content). Moreover, there are many kinds of composts. The effects that can be expected from various types of compost depend on the C\/N ratio, which is the ratio of carbon (C) and nitrogen (N) contained in the compost.
\u3000Therefore, Figure 1 summarizes what kind of compost can be used on what kind of soil for farmland with a history of cultivation.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-25.png\")
<\/figure><\/div>\n\n\n2. chemical fertilizers only have a nutrient effect<\/h3>\n\n\n\n
\u3000On the other hand, the effects of chemical fertilizers are not as diverse as those of compost. In other words, among the effects of compost, chemical fertilizers can only be expected to be effective as (1) nutrients. Only compost can be expected to improve the physical properties of the soil, such as the size and proportion of gaps in the soil (pore space distribution), ease of drainage (drainage property), water retention (water retention property), air permeability (aeration property), ease of cultivation (tillability), and various other effects as stable organic matter, as we pointed out in the 12th issue (June issue). The effects of compost alone can be expected only from compost.<\/p>\n\n\n\n
3. compost and chemical fertilizers differ in the onset of nutrient effects.<\/h3>\n\n\n\n
\u3000The effects of compost and chemical fertilizers differ in their effects as nutrients. As a rule, the nutrients in chemical fertilizers are in an inorganic form that is easily absorbed by crops. Moreover, they are manufactured so that when they are applied to the soil, they dissolve in the soil moisture and are absorbed by the crop. Therefore, the nutrient effect of chemical fertilizers is characterized by rapid action. If a crop shows signs of nutrient deficiency during its growth, the delay in growth can be corrected with additional chemical fertilizers. This is possible because chemical fertilizers are fast-acting.<\/p>\n\n\n\n
4. effect of stable organic matter on improving soil physical properties<\/h3>\n\n\n\n
\u3000On the other hand, the nutrients contained in compost are mostly in the organic form, with only a few in the inorganic form readily absorbed by crops. The organic nutrients are decomposed by soil microorganisms before they can be absorbed by the crop. Therefore, compost is a slow-acting nutrient that takes time to become effective. Therefore, it is not suitable for use as a fertilizer.
\u3000Of the nutrients contained in compost, the total amount of the fast-acting inorganic portion and the relatively easily degradable (readily degradable) organic portion can be expected to have a fertilizing effect on the soil in the same year they are applied to it. The rest of the organic portion, which takes more time to decompose (persistent), remains in the soil and is carried over to the next year and beyond as stable organic matter.
\u3000C\/N\u6bd4\u304c20\u672a\u6e80\u3068\u5c0f\u3055\u3044\u5806\u80a5\u306f\uff0c\u5206\u89e3\u3055\u308c\u3084\u3059\u3044\u3002\u305d\u306e\u305f\u3081\u990a\u5206\u52b9\u679c\u304c\u5f37\u304f\u8868\u308c\u308b\u3002\u9006\u306bC\/N\u6bd4\u304c30\u4ee5\u4e0a\u3068\u5927\u304d\u306a\u5806\u80a5\u306f\uff0c\u5206\u89e3\u3055\u308c\u306b\u304f\u304f\u5b89\u5b9a\u3057\u305f\u6709\u6a5f\u7269\u3068\u3057\u3066\u571f\u306b\u6b8b\u308b\u3002\u305d\u308c\u304c\u571f\u306e\u7269\u7406\u6027\u6539\u826f\u306e\u52b9\u679c\u3092\u3082\u305f\u3089\u3059\u3002<\/p>\n\n\n\n
5. chemical fertilizers have high nutrient content and are light in weight as materials<\/h3>\n\n\n\n
\u3000\u5316\u5b66\u80a5\u6599\u3068\u5806\u80a5\u306e\u990a\u5206\u306b\u3064\u3044\u3066\uff0c\u3082\u3046\u4e00\u3064\u91cd\u8981\u306a\u3061\u304c\u3044\u304c\u3042\u308b\u3002\u305d\u308c\u306f\u4e00\u5b9a\u306e\u91cd\u3055\u306b\u5bfe\u3057\u3066\u542b\u307e\u308c\u3066\u3044\u308b\u990a\u5206\u91cf\u306e\u3061\u304c\u3044\u3067\u3042\u308b\u3002\u5316\u5b66\u80a5\u6599\u306f\u5806\u80a5\u3088\u308a\u990a\u5206\u542b\u91cf\u304c\u6841\u3061\u304c\u3044\u306b\u591a\u3044\u3002\u305d\u306e\u305f\u3081\uff0c\u5316\u5b66\u80a5\u6599\u306e\u307b\u3046\u304c\u52b4\u50cd\u6642\u9593\u5f53\u305f\u308a\u306b\u4e0e\u3048\u3089\u308c\u308b\u990a\u5206\u91cf\u304c\u591a\u304f\uff0c\u5358\u4f4d\u990a\u5206\u91cf\u5f53\u305f\u308a\u306e\u904b\u642c\u30b3\u30b9\u30c8\u304c\u5b89\u3044\u3002\u4f8b\u3048\u3070\uff0c\u5e73\u5747\u7684\u306a\u5806\u80a5\uff08\u725b\u3075\u3093\u9ea6\u7a08\u5806\u80a5\uff09\u3068\u30c8\u30a6\u30e2\u30ed\u30b3\u30b7\u7528\u306e\u5316\u5b66\u80a5\u6599\u9298\u67c4\u300cS380\u300d\u53f7\u3092\u6bd4\u8f03\u3059\u308b\u3068\uff0c\u305d\u308c\u305e\u308c\u540c\u30581kg\u3092\u571f\u306b\u4e0e\u3048\u305f\u3068\u3057\u3066\u3082\uff0c\u5316\u5b66\u80a5\u6599\u306f\u7a92\u7d20\uff08N\uff09\u3067\u5806\u80a5\u306e130\u500d\uff0c\u30ea\u30f3\u306a\u3089(P2<\/sub>O5<\/sub>\u3068\u3057\u3066\uff0960\u500d\uff0c\u30ab\u30ea\u30a6\u30e0\u3067\u306f\uff08K2<\/sub>O\u3068\u3057\u3066)25\u500d\u3082\u591a\u304f\u4e0e\u3048\u3089\u308c\u308b\uff08\u8868\uff11) \u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-26.png\")
<\/figure><\/div>\n\n\n\u3000Because compost has a low nutrient content, the amount applied must be large in order to provide the large amount of nutrients needed to increase crop production. However, the amount is too large and labor-intensive. Chemical fertilizers, however, have made it possible to reduce this labor. This is because chemical fertilizers can provide large amounts of nutrients even in small amounts. Therefore, the use of chemical fertilizers has succeeded in greatly increasing the crop yield per area of land. Moreover, it also means an increase in production per labor hour. Thus, the production of food could be increased to support a large population.
\u3000The similarities and differences between compost and chemical fertilizers described above can be summarized in Table 2.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-27.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff13\u7ae0\u2212 \u690d\u7269\u306e\u990a\u5206\u5438\u53ce\u3068\u5438\u53ce\u3055\u308c\u305f\u990a\u5206\u306e\u690d\u7269\u4f53\u5185\u3067\u306e\u50cd\u304d
\u7b2c17\u56de\u3000\u690d\u7269\u304c\u6c34\u3068\u990a\u5206\u3092\u5438\u53ce\u3059\u308b\u3057\u304f\u307f
-Absorb necessary substances and eliminate unnecessary ones.<\/h2>\n\n\n\n
\u4ee4\u548c\uff14 (2022) \u5e74\u300012\u6708\u53f7 (\u7b2c746\u53f7)<\/p>\n\n\n\n
\u3000Plants absorb water and nutrients through their roots. However, the mechanism is not as simple as taking in substances dissolved in soil water (soil solution) into the roots at the same time as the solution.<\/p>\n\n\n\n
1. plant cells surrounded by cell membrane and cell wall<\/h3>\n\n\n\n
\u3000Plant cells are surrounded by a plasma membrane, which in turn is surrounded by a cell wall (Figure 1).
\u3000\u7d30\u80de\u58c1\u306f\u30b6\u30eb\u306e\u3088\u3046\u306a\u7db2\u76ee\u69cb\u9020\u3067\uff0c\u6c34\uff08\u3053\u3053\u3067\u306f\uff0c\u571f\u58cc\u6eb6\u6db2\u4e2d\u306e\u7269\u8cea\u3092\u6eb6\u304b\u3059\u6eb6\u5a92\u3068\u3057\u3066\u306e\u7d14\u6c34H2<\/sub>O\u306e\u3053\u3068\u3092\u610f\u5473\u3059\u308b\u3002\u4ee5\u4e0b\u540c\u69d8\uff09\u306f\u3082\u3061\u308d\u3093\uff0c\u571f\u58cc\u6eb6\u6db2\u306b\u6eb6\u3051\u3066\u3044\u308b\u6eb6\u8cea\u3068\u3057\u3066\u306e\u990a\u5206\u30a4\u30aa\u30f3\u3084\u305d\u306e\u4ed6\u306e\u591a\u304f\u306e\u7269\u8cea\u3082\uff0c\u81ea\u7531\u306b\u901a\u904e\u3067\u304d\u308b\u3002\u7d30\u80de\u58c1\u3092\u901a\u904e\u3057\u305f\u7269\u8cea\u306f\uff0c\u8449\u306e\u84b8\u6563\u4f5c\u7528\u306b\u3088\u3063\u3066\u4f5c\u3089\u308c\u308b\u690d\u7269\u4f53\u5185\u306e\u6c34\u306e\u6d41\u308c\u306b\u4e57\u308a\uff0c\u6839\u306e\u4e2d\u5fc3\u67f1\u3092\u53d6\u308a\u56f2\u3080\u5185\u76ae\uff08\u56f3\uff11\u306e\u2463\u3067\uff0c\u4e00\u3064\u305a\u3064\u306e\u7d30\u80de\u304c\u8f2a\u3092\u3064\u304f\u308b\u3088\u3046\u306b\u3064\u306a\u304c\u3063\u3066\u3044\u308b\u7d44\u7e54\uff09\u307e\u3067\u305f\u3069\u308a\u7740\u304f\u3002\u3053\u308c\u304c\u56f3\uff11\u306e\u2460\u306e\u79fb\u52d5\u7d4c\u8def\u3067\u3042\u308b\u3002\u3053\u3053\u307e\u3067\u306f\u307e\u3060\u7d30\u80de\u819c\u306e\u5916\u3067\u3042\u308a\uff0c\u6c34\u3068\u990a\u5206\u30a4\u30aa\u30f3\u306f\u7d30\u80de\u819c\u306e\u5185\u5074\u306b\u5165\u3063\u3066\u3044\u306a\u3044\u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-28.jpg\")
<\/figure><\/div>\n\n\n\uff12\uff0e\u7d30\u80de\u819c\u5185\u306b\u5165\u308b\u6700\u5f8c\u306e\u969c\u58c1
\u3000\u2212\u30ab\u30b9\u30d1\u30ea\u30fc\u7dda<\/h3>\n\n\n\n
\u3000The cell wall of the endothelium is surrounded by a ribbon-like band of tissue called the cuspary line (Figure 1). Water and nutrient ions that have passed through the cell wall along the path shown in Fig. 1 (1) arrive at the cuspary line, where they are blocked and cannot move to the central column. This is because the cuspary line is made up of lignin, the main component of wood, and suberin, a type of lipid, and does not allow substances to pass through freely.
\u3000Apart from the pathway (1), there is another pathway where water and nutrient ions suddenly pass through the root hair cell membrane and move inside the cell (pathway (2) in Figure 1). In this case, the cell membrane that is first attempted to pass through determines whether it is allowed to enter the inside of the membrane. Only substances that are allowed to enter the membrane pass through the cell membrane. The next cell passes through the protoplasmic contact, which is a groove between cells. In this pathway, the endothelial cells can also pass through the endothelium and travel to the side of the central column ducts, since they have first entered the plasma membrane.
\u3000The problem is how it is allowed to enter the plasma membrane when it attempts to pass through the endothelial cell caspary line in pathway (1) and when it first passes through the plasma membrane in pathway (2), respectively.<\/p>\n\n\n\n
3. cell membrane function and water absorption
\u3000-Osmotic pressure and transport proteins (aquaporins)<\/h3>\n\n\n\n
\u3000The cell membrane is composed of a bilayer of phospholipids consisting of hydrophilic and hydrophobic groups with hydrophobic groups next to each other (Figure 2). As shown in the figure, there are membrane-spanning proteins, which together constitute the cell membrane. These membrane-spanning proteins are called transport proteins, and play a major role in the transport of substances across the plasma membrane.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-28.png\")
<\/figure><\/div>\n\n\n\u3000\u3053\u306e\u7d30\u80de\u819c\u306f\u7d30\u80de\u5185\u306e\u69d8\u3005\u306a\u7269\u8cea\u3092\u62b1\u3048\u3066\u3044\u308b\u306e\u3067\uff0c\u4e00\u822c\u306b\uff0c\u7269\u8cea\u6fc3\u5ea6\u306f\u7d30\u80de\u819c\u5185\u3067\u9ad8\u304f\uff0c\u819c\u5916\u306f\u4f4e\u3044\u3002\u7d30\u80de\u819c\u304c\u7d30\u80de\u58c1\u306e\u3088\u3046\u306b\uff0c\u3059\u3079\u3066\u306e\u7269\u8cea\u306e\u901a\u904e\u3092\u8a31\u3059\u5168\u900f\u819c\u3067\u3042\u308c\u3070\uff0c\u901a\u5e38\u306f\u6fc3\u5ea6\u52fe\u914d\u306b\u3088\u308b\u62e1\u6563\u306b\u3088\u3063\u3066\uff0c\u6fc3\u5ea6\u306e\u9ad8\u3044\u7d30\u80de\u5185\u304b\u3089\u6fc3\u5ea6\u306e\u4f4e\u3044\u819c\u5916\u306b\u990a\u5206\u30a4\u30aa\u30f3\u304c\u51fa\u3066\u3044\u304f\u3002\u3053\u308c\u3067\u306f\uff0c\u990a\u5206\u30a4\u30aa\u30f3\u304c\u990a\u5206\u3068\u3057\u3066\u5229\u7528\u3067\u304d\u306a\u304f\u306a\u308b\u3002
\u3000\u3053\u306e\u305f\u3081\uff0c\u7d30\u80de\u819c\u306f\u6eb6\u5a92\u306e\u6c34\u3092\u901a\u904e\u3055\u305b\u308b\u304c\uff0c\u6eb6\u8cea\u306e\u990a\u5206\u30a4\u30aa\u30f3\u306a\u3069\u306e\u7269\u8cea\u3092\u901a\u904e\u3055\u305b\u306a\u3044\u534a\u900f\u819c\u306b\u306a\u3063\u3066\u3044\u308b\u3002\u3053\u306e\u6642\u6c34\u306f\uff0c\u7d30\u80de\u819c\u306e\u5185\u5916\u306e\u6fc3\u5ea6\u5dee\u3092\u6d88\u3059\u3088\u3046\u306b\uff0c\u9ad8\u6fc3\u5ea6\u306e\u7d30\u80de\u819c\u5185\u5074\u306b\u5165\u308a\u8fbc\u3093\u3067\u5438\u53ce\u3055\u308c\u308b\u3002\u3053\u306e\u534a\u900f\u819c\u306e\u5185\u5916\u306e\u6fc3\u5ea6\u5dee\u3067\u767a\u751f\u3059\u308b\u5727\u529b\u304c\u6d78\u900f\u5727\u3067\u3042\u308b\u3002\u3068\u3053\u308d\u304c\uff0c\u6d78\u900f\u5727\u3060\u3051\u306e\u6c34\u306e\u79fb\u52d5\u901f\u5ea6\u306f\u9045\u304f\uff0c\u690d\u7269\u306e\u6c34\u8981\u6c42\u3092\u5341\u5206\u306b\u6e80\u305f\u305b\u306a\u3044\u3002\u305d\u308c\u3092\u88dc\u3046\u6c34\u306e\u8f38\u9001\u30bf\u30f3\u30d1\u30af\u8cea\u304c\u30a2\u30af\u30a2\u30dd\u30ea\u30f3\uff08\u6c34\u30c1\u30e3\u30cd\u30eb\u3068\u3082\u3044\u3046\uff09\u3067\uff0c\u6c34\u306e\u8f38\u9001\u901f\u5ea6\u306f\u975e\u5e38\u306b\u901f\u3044\u3002\u591a\u304f\u306e\u690d\u7269\u7d30\u80de\u3067\u306f\uff0c\u30a2\u30af\u30a2\u30dd\u30ea\u30f3\u306b\u3088\u3063\u3066\u6c34\u306e\u8f38\u9001\u901f\u5ea6\u304c10\u500d\u4ee5\u4e0a\u9ad8\u307e\u308b(\u5e73\u6ca2\uff0c2016) \u3002\u690d\u7269\u304c\u571f\u58cc\u6eb6\u6db2\u304b\u3089\u6c34\u3092\u5438\u53ce\u3059\u308b\u306e\u306f\uff0c\u4e3b\u306b\u30a2\u30af\u30a2\u30dd\u30ea\u30f3\u306e\u50cd\u304d\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
\uff14\uff0e\u990a\u5206\u304c\u7d30\u80de\u819c\u3092\u901a\u904e\u3059\u308b\u3057\u304f\u307f
\u3000\u2212\u8f38\u9001\u30bf\u30f3\u30d1\u30af\u8cea\u306b\u3088\u308b\u80fd\u52d5\u8f38\u9001<\/h3>\n\n\n\n
\u3000Transport proteins are also responsible for the entry of nutrient ions dissolved in the soil solution into the plasma membrane. Nutrient ions, which are solutes in the soil solution, cannot pass through the cell membrane, which is a semipermeable membrane. Moreover, since there is a concentration gradient between the inside and outside of the plasma membrane, nutrient ions must enter the plasma membrane against the concentration gradient in order to be absorbed. This is made possible by the function of transport proteins that penetrate the plasma membrane.
\u3000These transport proteins do not freely transport any substance, but have their own specific transport partners. As already mentioned, water is transported by aquaporin, a water-specific transport protein. Ammonium ions, the nutrient ions of nitrogen, have a transport protein (ammonium ion transporter) that is responsible for their passage through the membrane. Plants are able to selectively take up only the nutrient ions they need from a soil solution containing various substances (selective absorption) because each transport protein has the property of transporting its own counterpart. At this time, there are also transport proteins that generate energy to transport nutrient ions from the outside to the inside of the membrane against the concentration gradient (active transport).
\u3000Thus, plants skillfully selectively absorb only water and nutrient ions from substances dissolved in the soil solution around their roots, eliminating unwanted substances.<\/p>\n\n\n\n
5. the final step in nutrient absorption is transfer to the ducts<\/h3>\n\n\n\n
\u3000Absorbed water and nutrient ions do not remain in the root cells. The absorbed water and nutrient ions are transferred to the various parts of the plant body, such as the stem and leaves. This is done through ducts. Since ducts are pipes for transport, they are the outer tissues of the plasma membrane and consist mainly of cell walls.
\u3000Therefore, water and nutrient ions that enter the endothelial cell must again move out of the plasma membrane and into the ducts (Fig. 1, movement \u2464). The transport protein that performs this role is often not the same transport protein that was used to enter the plasma membrane, but another transport protein.
\u3000Thus, water and nutrient ions that reach the ducts move to the plant organs where they are needed, where they are used as nutrients and converted into substances that nourish the plant.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff13\u7ae0\u2212 \u690d\u7269\u306e\u990a\u5206\u5438\u53ce\u3068\u5438\u53ce\u3055\u308c\u305f\u990a\u5206\u306e\u690d\u7269\u4f53\u5185\u3067\u306e\u50cd\u304d
\u7b2c18\u56de\u3000\u690d\u7269\u304c\u96e3\u6eb6\u6027\u7269\u8cea\u3092\u5438\u53ce\u3059\u308b\u3057\u304f\u307f
\u2212\u6839\u304b\u3089\u6eb6\u89e3\u3092\u52a9\u3051\u308b\u7269\u8cea\u3092\u5206\u6ccc\u3059\u308b\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u3000\uff11\u6708\u53f7 (\u7b2c747\u53f7)<\/p>\n\n\n\n
\u3000Plants select and absorb the nutrients they need from the water (soil solution) in the soil. In the last issue, I explained how this works. If nutrients are easily soluble in soil solution, it was explained. But what do plants do when nutrients exist in the soil as insoluble substances that are difficult to dissolve in water?
\u3000In this article, I would like to look at the amazing mechanism by which plants absorb nutrients from substances that are difficult to dissolve in soil solution.<\/p>\n\n\n\n
1. phosphorus and iron are insoluble substances in the field<\/h3>\n\n\n\n
\u3000Among plant nutrients, phosphorus and iron exist in the soil in the form of substances that are insoluble in water (insoluble substances, such as aluminum phosphate, iron phosphate, and iron hydroxide). However, when the soil surface is covered with water and the soil is in a reduced state due to lack of oxygen, as in paddy fields, the insoluble iron phosphate and iron hydroxide are transformed into water-soluble substances. Therefore, rice plants are seldom significantly deficient in these nutrients.
\u3000On the other hand, in field soil, oxygen is connected to the atmosphere and remains in an oxidized state. For this reason, phosphorus and iron exist as insoluble substances, which are difficult to dissolve in soil solution, making them difficult for plants to absorb. However, plants absorb such nutrients by taking measures as described below.<\/p>\n\n\n\n
2. mechanism of phosphorus absorption from insoluble phosphorus<\/h3>\n\n\n\n
\u3000In field conditions, phosphorus is often present as the insoluble substances aluminum phosphate and iron phosphate. In addition, phosphorus may also be present in the form of organic phosphorus, which cannot be absorbed without modification. To facilitate the absorption of such water-insoluble phosphorus, plants produce organic acids (citric acid, oxalic acid, piscic acid, etc.) and an enzyme called acid phosphatase in the root cells and discharge them into the soil around the roots (this phenomenon is called secretion) (Figure 1). Of course, these secreted substances must also pass through the cell membrane to exit the root. The transport of these substances is handled by the respective transport proteins (transporters).
\u3000Organic acids secreted by the roots have the ability to dissolve iron phosphate and aluminum phosphate in the soil by stripping their bonds. The dissolved phosphorus in ionic form is transported into the cell membrane through transport proteins and absorbed by the plant. The iron and aluminum that are stripped from their bonds do not remain in the soil solution as ions. They are transformed by organic acids into an encapsulated form (this kind of reaction is called chelation, and the resulting substance is called a chelating substance), which prevents them from rejoining phosphorus.
\u3000Acid phosphatases act on the organic phosphorus present around the roots and deliver water-soluble phosphate ions to the soil solution by enzymatic degradation (Figure 1). The delivered phosphate ions are absorbed into the cell membrane through transport proteins as plant nutrients.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-29.png\")
<\/figure><\/div>\n\n\n3. expand rooting to absorb phosphorus<\/h3>\n\n\n\n
\u3000Since phosphorus exists as an insoluble substance, the concentration of phosphorus in the soil solution is low. Therefore, plants sometimes try to absorb phosphorus in low concentrations by increasing root growth and expanding the root surface area. A similar mechanism is used by filamentous fungi (a member of the fungus family, mycorrhizal fungi) that live symbiotically in the roots. Mycorrhizal fungi spread their mycelium widely in the soil, take up phosphorus from the soil solution, and provide it to the host plant, which in turn supplies phosphorus to the plant.<\/p>\n\n\n\n
4. two mechanisms of iron absorption from insoluble iron<\/h3>\n\n\n\n
\u3000\u7551\u72b6\u614b\u306e\u9244\u306f\u96e3\u6eb6\u6027\u306e\u9178\u5316\u9244\uff08\u3053\u308c\u306f\uff0c\u9244\u306e\u30b5\u30d3\u3068\u540c\u3058\u7269\u8cea\u3002\u3053\u306e\u9244\u306e\u5f62\u614b\u306f\uff0c\u4e09\u4fa1\u9244\u30fbFe(\u2162)\u30fbFe3<\/sup>\u207a\uff09\u3067\u571f\u306e\u4e2d\u306b\u5b58\u5728\u3057\uff0c\u571f\u58cc\u6eb6\u6db2\u306b\u306f\u6eb6\u3051\u306b\u304f\u3044\u3002\u3053\u306e\u307e\u307e\u3067\u3042\u308c\u3070\uff0c\u690d\u7269\u306f\u9244\u3092\u5438\u53ce\u3057\u306b\u304f\u304f\u6b20\u4e4f\u3057\u3066\u3057\u307e\u3046\u3002\u3057\u304b\u3057\uff0c\u7551\u72b6\u614b\u3067\u751f\u80b2\u3059\u308b\u690d\u7269\u306f\uff0c\u30ea\u30f3\u306e\u5834\u5408\u3068\u540c\u3058\u3088\u3046\u306b\u6839\u304b\u3089\u96e3\u6eb6\u6027\u306e\u9244\uff08\u4e09\u4fa1\u9244\uff09\u3092\u6eb6\u304b\u3059\u7269\u8cea\u3092\u5206\u6ccc\u3059\u308b\u3053\u3068\u3067\u9244\u3092\u5438\u53ce\u3057\u3066\u3044\u308b\u3002\u305f\u3060\u3057\uff0c\u30a4\u30cd\u79d1\u4ee5\u5916\u306e\u690d\u7269\u3068\u30a4\u30cd\u79d1\u690d\u7269\u3068\u3067\u306f\uff0c\u9244\u5438\u53ce\u306e\u3057\u304f\u307f\u304c\u5927\u304d\u304f\u3061\u304c\u3046(\u56f3\uff12) \u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-30.jpg\")
<\/figure><\/div>\n\n\n(1) Mechanism of iron absorption in plants other than grasses<\/h4>\n\n\n\n
\u3000\u3053\u308c\u306fStrategy\u2212\u2160(\u6226\u7565\u2212\u2160\uff09\u3068\u3044\u308f\u308c\u308b\uff08\u56f3\uff12\u306e\u5de6\u5074) \u3002\u307e\u305a\uff0c\u96e3\u6eb6\u6027\u9244\uff08\u4e09\u4fa1\u9244\uff09\u3092\u6eb6\u304b\u3059\u3086\u308b\u3044\u30ad\u30ec\u30fc\u30c8\u7269\u8cea\uff08\u30d5\u30a7\u30ce\u30fc\u30eb\u6027\u9178\uff09\u3092\u6839\u304b\u3089\u5206\u6ccc\u3059\u308b\u3002\u3053\u306e\u7269\u8cea\u3067\u4e09\u4fa1\u9244\u3092\u5305\u307f\u8fbc\u3093\u3067\uff08\u30ad\u30ec\u30fc\u30c8\u5316\u3057\u3066\uff09\u7d30\u80de\u58c1\u306b\u6301\u3061\u8fbc\u3080\u3002\u3059\u308b\u3068\uff0c\u7d30\u80de\u819c\u8868\u9762\u306b\u5b58\u5728\u3057\u3066\u3044\u308b\u9175\u7d20\uff08\u4e09\u4fa1\u9244\u9084\u5143\u9175\u7d20\uff0cFRO)\u304c\u50cd\u304d\uff0c\u4e09\u4fa1\u9244\u3092\u4e8c\u4fa1\u9244\uff08Fe\uff08\u2161)\u30fbFe2<\/sup>\u207a\uff09\u306b\u5909\u3048\u308b\u3002\u305d\u3057\u3066\u3053\u306e\u4e8c\u4fa1\u9244\u306e\u8f38\u9001\u30bf\u30f3\u30d1\u30af\u8cea\uff08IRT)\u306b\u3088\u3063\u3066\u7d30\u80de\u819c\u5185\u306b\u5438\u53ce\u3055\u308c\u308b\u3002
\u3000Other mechanisms utilize trivalent iron, which is more soluble in acidic conditions. There is a transport protein (proton pump, HA) that releases hydrogen ions from root cells to the outside of the root. This proton pump lowers the pH around the roots, making it easier for trivalent iron to dissolve in water and be absorbed.<\/p>\n\n\n\n(2) Mechanism of iron absorption by rice plants<\/h4>\n\n\n\n
\u3000This is known as Strategy-II (right side of Figure 2). Organic acids such as mugineic acids and their analogues (MAs in the figure, see note in Figure 2 for explanation of the English letters), which are produced by the plant inside the root cells, are secreted outside the cell wall around the root through a transport protein (TOM1). This acts on trivalent iron, which is transformed into a substance (chelate called Fe(III)-MAs) encapsulated in mugineic acids. The chelates made from the iron and mugineic acids are absorbed into the plasma membrane by transport proteins (YS1 and YSL) responsible for their transport (Nozoe et al., 2014).
\u3000This mugineic acid was discovered by Professor Seiichi Takagi of Iwate University in Japan in 1976. Until then, the mechanism of iron absorption by plants other than grasses could not fully explain the iron absorption of grasses. However, this discovery clarified the mechanism. This was truly a major historical discovery.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff13\u7ae0\u2212 \u690d\u7269\u306e\u990a\u5206\u5438\u53ce\u3068\u5438\u53ce\u3055\u308c\u305f\u990a\u5206\u306e\u690d\u7269\u4f53\u5185\u3067\u306e\u50cd\u304d
\u7b2c19\u56de\u3000\u5438\u53ce\u3055\u308c\u305f\u7a92\u7d20\u304c\u30bf\u30f3\u30d1\u30af\u8cea\u306b\u306a\u308b\u307e\u3067
\u2212\u690d\u7269\u306f\u5fc5\u8981\u306a\u30a2\u30df\u30ce\u9178\u3092\u3059\u3079\u3066\u81ea\u7d66\u3059\u308b\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74 2\/3\u6708\u5408\u4f75\u53f7 (\u7b2c748\u53f7)<\/p>\n\n\n\n
\u3000Plants select and absorb only the nutrients they need from the water in the soil (soil solution) by a well-developed mechanism. The absorbed nutrient ions support the nutrition of the plant by either becoming components of substances that help to nourish the plant or by participating in various reactions in the plant body.
\u3000This month, as an example, we will look at how plants use nitrogenous nutrient ions such as ammonium and nitrate ions and carbohydrates produced by photosynthesis in leaves to make proteins.<\/p>\n\n\n\n
1. how amino acids are synthesized from ammonium ions<\/h3>\n\n\n\n
\u3000\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\uff08NH4<\/sub>\u207a\uff09\u306e\u7a92\u7d20\uff08N\uff09\u3084\u6c34\u7d20\uff08H\uff09\u306f\uff0c\u30bf\u30f3\u30d1\u30af\u8cea\u306e\u69cb\u6210\u6210\u5206\u3067\u690d\u7269\u306e\u91cd\u8981\u306a\u990a\u5206\u3067\u3042\u308b\u3002\u3057\u304b\u3057\uff0c\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u304c\u591a\u91cf\u306b\u690d\u7269\u306e\u5730\u4e0a\u90e8\u306b\u9001\u308a\u8fbc\u307e\u308c\u308b\u3068\u5149\u5408\u6210\u3092\u59a8\u5bb3\u3059\u308b\u306a\u3069\uff0c\u690d\u7269\u306b\u60aa\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u3002\u3053\u306e\u305f\u3081\uff0c\u591a\u304f\u306e\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306f\u6839\u306e\u7d30\u80de\u5185\u306b\u3068\u308a\u3053\u307e\u308c\u308b\u3068\uff0c\u3059\u3050\u306b\u30a2\u30df\u30ce\u9178\u306b\u5408\u6210\u3055\u308c\u3066\u7121\u6bd2\u5316\u3055\u308c\u308b\u3002\u305d\u306e\u7d4c\u8def\u3092\u793a\u3057\u305f\u306e\u304c\u56f3\uff11\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-30.png\")
<\/figure><\/div>\n\n\n\u3000\u690d\u7269\u306e\u6839\u306e\u7d30\u80de\u306b\u3068\u308a\u3053\u307e\u308c\u305f\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306f\uff0c\u307e\u305a\u30b0\u30eb\u30bf\u30df\u30f3\u9178\u3068\u3044\u3046\u30a2\u30df\u30ce\u9178\u3068\u7d50\u5408\u3057\u3066\u30b0\u30eb\u30bf\u30df\u30f3\u3068\u3044\u3046\u30a2\u30df\u30ce\u9178\u306b\u306a\u308b\u3002\u3053\u306e\u53cd\u5fdc\u306f\u30b0\u30eb\u30bf\u30df\u30f3\u5408\u6210\u9175\u7d20\u306e\u50cd\u304d\u3067\u3042\u308b\u3002\u3053\u306e\u30b0\u30eb\u30bf\u30df\u30f3\u306f\uff0c\u5149\u5408\u6210\u3067\u3064\u304f\u3089\u308c\u305f\u70ad\u6c34\u5316\u7269\u304c\uff0c\u690d\u7269\u306e\u547c\u5438\u306b\u3088\u3063\u3066\u5206\u89e3\u3055\u308c\u308b\u904e\u7a0b\u306e\u4e2d\u9593\u7523\u7269\u3067\u3042\u308b2\u2212\u30aa\u30ad\u30bd\u30b0\u30eb\u30bf\u30fc\u30eb\u9178\u3068\u3044\u3046\u6709\u6a5f\u9178\u3068\u53cd\u5fdc\u3057\u3066\uff0c\u4e8c\u3064\u306e\u30b0\u30eb\u30bf\u30df\u30f3\u9178\u306b\u5909\u308f\u308b\u3002\u3053\u306e\u53cd\u5fdc\u306f\uff0c\u30b0\u30eb\u30bf\u30df\u30f3\u9178\u5408\u6210\u9175\u7d20\u306e\u50cd\u304d\u3067\u3042\u308b\u3002
\u3000Of the two glutamic acids, one is again combined with ammonium ions to make glutamine. The other reacts with various organic acids, which are intermediate products of the breakdown of photosynthetic products by plant respiration, to produce the necessary amino acids. In this case, the reactions are also carried out by enzymes that assist in each reaction. In this way, all necessary amino acids are self-sufficient, and proteins are synthesized from them.<\/p>\n\n\n\n
2. how amino acids are synthesized from nitrate ions<\/h3>\n\n\n\n
\u3000\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306f\u56f3\uff11\u306e\u7d4c\u8def\u3067\u30a2\u30df\u30ce\u9178\u5408\u6210\u304c\u304a\u3053\u306a\u308f\u308c\u308b\u3002\u3068\u3053\u308d\u304c\uff0c\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306f\uff0c\u7551\u306e\u3088\u3046\u306b\u7a7a\u6c17\u4e2d\u306e\u9178\u7d20\u306b\u89e6\u308c\u3084\u3059\u3044\u6761\u4ef6\uff08\u9178\u5316\u6761\u4ef6\uff09\u3067\u306f\uff0c\u571f\u306e\u5fae\u751f\u7269\u306e\u50cd\u304d\u3067\u785d\u9178\u30a4\u30aa\u30f3\u306b\u5909\u5316\u3059\u308b\u3002\u3053\u308c\u304c\u785d\u9178\u5316\u6210\u4f5c\u7528\u3067\u3042\u308b\u3002\u3057\u305f\u304c\u3063\u3066\u7551\u4f5c\u7269\u306a\u3069\u304c\u5438\u53ce\u3059\u308b\u990a\u5206\u3068\u3057\u3066\u306e\u7a92\u7d20\u306e\u5f62\u614b\u306f\u785d\u9178\u30a4\u30aa\u30f3\u304c\u4e3b\u4f53\u3067\u3042\u308b\u3002\u3053\u306e\u5834\u5408\uff0c\u3069\u306e\u3088\u3046\u306b\u3057\u3066\u30a2\u30df\u30ce\u9178\u304c\u5408\u6210\u3055\u308c\uff0c\u30bf\u30f3\u30d1\u30af\u8cea\u306e\u6750\u6599\u3068\u306a\u308b\u306e\u3060\u308d\u3046\u304b\u3002\u3053\u3053\u3067\u3082\u690d\u7269\u306f\u305f\u304f\u307f\u306a\u3057\u304f\u307f\u3092\u7528\u610f\u3057\u3066\u3044\u308b\u3002
\u3000\u690d\u7269\u306b\u5438\u53ce\u3055\u308c\u305f\u785d\u9178\u30a4\u30aa\u30f3\u304c\u30a2\u30df\u30ce\u9178\u306e\u539f\u6599\u3068\u306a\u308b\u306b\u306f\uff0c\u785d\u9178\u30a4\u30aa\u30f3\u304c\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306b\u5909\u5316\u3057\uff0c\u56f3\uff11\u306e\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u304b\u3089\u30a2\u30df\u30ce\u9178\u5408\u6210\u3055\u308c\u308b\u3057\u304f\u307f\uff08GS-GOGAT\u30b7\u30b9\u30c6\u30e0\u3068\u3044\u3046\uff09\u306b\u7d44\u307f\u8fbc
\u307e\u308c\u3066\u3044\u304f\u5fc5\u8981\u304c\u3042\u308b\u3002\u305d\u306e\u50cd\u304d\u3092\u304a\u3053\u306a\u3046\u306e\u304c\u785d\u9178\u9084\u5143\u9175\u7d20\u3068\u4e9c\u785d\u9178\u9084\u5143\u9175\u7d20\u3067\u3042\u308b\uff08\u56f3\uff12) \u3002\u3044\u305a\u308c\u3082\u9175\u7d20\u53cd\u5fdc\u3067\uff0c\u5354\u540c\u3057\u3066\u785d\u9178\u30a4\u30aa\u30f3\u3092\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u3078\u5909\u5316\u3055\u305b\u308b\u3002
\u3000\u591a\u304f\u306e\u785d\u9178\u30a4\u30aa\u30f3\u306f\u6839\u3067\u5438\u53ce\u3055\u308c\u308b\u3068\uff0c\u305d\u306e\u307e\u307e\u306e\u5f62\u614b\u3067\u9053\u7ba1\u3092\u901a\u3063\u3066\u8449\u3078\u79fb\u52d5\u3059\u308b\u3002\u8449\u306f\u65e5\u5149\u306b\u3088\u304f\u7167\u3089\u3055\u308c\uff0c\u3053\u306e\u9175\u7d20\u53cd\u5fdc\u306b\u5fc5\u8981\u306a\u5149\u30a8\u30cd\u30eb\u30ae\u30fc\u3092\u7372\u5f97\u3057\u3084\u3059\u3044\u304b\u3089\u3067\u3042\u308b\u3002\u8449\u3078\u79fb\u52d5\u3057\u305f\u785d\u9178\u30a4\u30aa\u30f3\u306f\uff0c\u785d\u9178\u9084\u5143\u9175\u7d20\u306e\u50cd\u304d\u3067\u4e9c\u785d\u9178\u30a4\u30aa\u30f3\u306b\u5909\u5316\u3059\u308b\u3002\u3055\u3089\u306b\u4e9c\u785d\u9178\u30a4\u30aa\u30f3\u306f\uff0c\u4e9c\u785d\u9178\u9084\u5143\u9175\u7d20\u3067\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306b\u5909\u5316\u3059\u308b\u3002\u305d\u3057\u3066\uff0c\u30a2\u30df\u30ce\u9178\u5408\u6210\u7d4c\u8def\u306eGS-GOGAT\u30b7\u30b9\u30c6\u30e0\u306b\u5165\u308a(\u56f3\uff12) \uff0c\u5fc5\u8981\u306a\u30a2\u30df\u30ce\u9178\u5408\u6210\u304c\u304a\u3053\u306a\u308f\u308c\u308b\u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-31.png\")
<\/figure><\/div>\n\n\n3. mechanism to prevent excessive accumulation of ammonium ions<\/h3>\n\n\n\n
\u3000The issue here is the relationship between the rate of the enzymatic reaction that converts nitrate to ammonium ions and the rate at which the resulting ammonium ions are incorporated into the GSGOGAT system for amino acid synthesis. If the rate of the former exceeds that of the latter, the ammonium ions produced by this enzymatic reaction will accumulate in the leaves. However, this must be avoided. The accumulation of ammonium ions is detrimental to the plant. To avoid this, nitrate reductase has a function that prevents the accumulation of ammonium ions.
\u3000\u785d\u9178\u9084\u5143\u9175\u7d20\u306f\u785d\u9178\u30a4\u30aa\u30f3\u304c\u5438\u53ce\u3055\u308c\u308b\u3053\u3068\u3067\u9175\u7d20\u53cd\u5fdc\u3092\u6d3b\u6027\u5316\u3055\u305b\uff0c\u4e9c\u785d\u9178\u30a4\u30aa\u30f3\u3092\u3064\u304f\u308b\u3002\u3057\u304b\u3057\uff0c\u3053\u306e\u4e9c\u785d\u9178\u30a4\u30aa\u30f3\u304c\u4e9c\u785d\u9178\u9084\u5143\u9175\u7d20\u306e\u50cd\u304d\u3067\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306b\u306a\u308b\u3068\uff0c\u305d\u308c\u304c\u30a2\u30df\u30ce\u9178\u5408\u6210\u306b\u7d44\u307f\u5165\u308c\u3089\u308c\u3066\u7d30\u80de\u5185\u3067\u7121\u6bd2\u5316\u3055\u308c\u308b\u307e\u3067\uff0c\u785d\u9178\u9084\u5143\u9175\u7d20\u306f\u81ea\u8eab\u306e\u9175\u7d20\u6d3b\u6027\u3092\u6291\u5236\u3059\u308b\u3002\u3064\u307e\u308a\uff0c\u785d\u9178\u9084\u5143\u9175\u7d20\u306f\u3080\u3084\u307f\u306b\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u3092\u3064\u304f\u3089\u306a\u3044\u3088\u3046\u306b\u9175\u7d20\u6d3b\u6027\u3092\u81ea\u5df1\u898f\u5236\u3057\u3066\u3044\u308b\u3002\u3053\u308c\u306b\u3088\u3063\u3066\uff0c\u785d\u9178\u30a4\u30aa\u30f3\u304c\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u306b\u5909\u63db\u3055\u308c\u308b\u901f\u5ea6\u3068\uff0c\u9175\u7d20\u53cd\u5fdc\u3067\u3067\u304d\u305f\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u304c\u30a2\u30df\u30ce\u9178\u3078\u5909\u63db\u3055\u308c\u308b\u901f\u5ea6\u3068\u306e\u9593\u3067\u30d0\u30e9\u30f3\u30b9\u304c\u7dad\u6301\u3055\u308c\u3066\u3044\u308b\u3002\u3053\u306e\u785d\u9178\u9084\u5143\u9175\u7d20\u306e\u3088\u3046\u306b\uff0c\u72b6\u6cc1\u306b\u5fdc\u3058\u3066\u76ee\u7684\u306b\u304b\u306a\u3046\u3088\u3046\u306b\u53cd\u5fdc\u6d3b\u6027\u306e\u8abf\u7bc0\u6a5f\u80fd\u3092\u6301\u3064\u9175\u7d20\u3092\u9069\u5fdc\u9175\u7d20\u3042\u308b\u3044\u306f\u8a98\u5c0e\u9175\u7d20\u3068\u3044\u3046\u3002
\u3000The fact that nitrate reductase is an adaptive enzyme is especially important for many plants that mainly absorb nitrate as a nitrogen nutrient source, in order to avoid the danger of excessive accumulation of ammonium ions.<\/p>\n\n\n\n
4. the only external raw material required for amino acid synthesis is ammonium ions<\/h3>\n\n\n\n
\u3000From what we have seen so far about the mechanism of amino acid synthesis, we can notice something. The only raw material that plants need to acquire from outside in order to synthesize amino acids is ammonium ions. The other raw material, photosynthetic products (carbohydrates), is synthesized by the plant itself. This is made possible by two enzymes that synthesize glutamine and glutamic acid. It is thanks to the action of these two enzymes that plants are able to synthesize complex amino acids from simple substances such as ammonium ions.<\/p>\n\n\n\n
5. plants do not contain essential amino acids<\/h3>\n\n\n\n
\u79c1\u9054\u306f\uff0c\u30bf\u30f3\u30d1\u30af\u8cea\u306e\u5408\u6210\u306b\u5fc5\u8981\u306a\u30a2\u30df\u30ce\u9178\u306e\u3059\u3079\u3066\u3092\u81ea\u7d66\u3067\u304d\u306a\u3044\u3002\u305d\u306e\u305f\u3081\uff0c\u98df\u3079\u3082\u306e\u304b\u3089\u5fc5\u8981\u306a\u30a2\u30df\u30ce\u9178\u3092\u7372\u5f97\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u3002\u3053\u308c\u304c\u5fc5\u9808\u30a2\u30df\u30ce\u9178\u3067\u3042\u308b\u3002\u690d\u7269\u306f\u30bf\u30f3\u30d1\u30af\u8cea\u306e\u5408\u6210\u306b\u5fc5\u8981\u306a\u3059\u3079\u3066\u306e\u30a2\u30df\u30ce\u9178\u3092\u81ea\u7d66\u3059\u308b\u306e\u3067\uff0c\u690d\u7269\u306b\u5fc5\u9808\u30a2\u30df\u30ce\u9178\u306f\u306a\u3044\u3002\u52d5\u7269\u306e\u5fc5\u9808\u30a2\u30df\u30ce\u9178\u306e\u3088\u3046\u306a\u7269\u8cea\u304c\u690d\u7269\u306b\u3082\u3042\u308b\u3068\u3044\u3046\u3088\u3046\u306a\u8aa4\u89e3\u306f\u907f\u3051\u308b\u3079\u304d\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff13\u7ae0\u2212 \u690d\u7269\u306e\u990a\u5206\u5438\u53ce\u3068\u5438\u53ce\u3055\u308c\u305f\u990a\u5206\u306e\u690d\u7269\u4f53\u5185\u3067\u306e\u50cd\u304d
\u7b2c20\u56de\u3000\u8fb2\u7523\u7269\u306e\u304a\u3044\u3057\u3055\u306b\u5f71\u97ff\u3059\u308b
\u30bf\u30f3\u30d1\u30af\u8cea\u3068\u70ad\u6c34\u5316\u7269\u306f\u30c8\u30ec\u30fc\u30c9\u30aa\u30d5\u306e\u95a2\u4fc2<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u3000\uff14\u6708\u53f7 (\u7b2c749\u53f7)<\/p>\n\n\n\n
\u3000In the previous issue, we introduced the GS-GOGAT system, in which plants absorb ammonium and nitrate ions, which are nitrogenous nutrient ions, and utilize carbohydrates produced by photosynthesis in leaves to produce amino acids, which are the raw materials for proteins. Using this system, plants supply themselves with all the amino acids necessary for protein synthesis. Proteins, along with carbohydrates, greatly affect the taste of agricultural products.
\u3000In this article, we will consider the curious trade-off between protein and carbohydrate content in crops, which has a significant impact on the taste of agricultural products, from the perspective of the GS-GOGAT system.<\/p>\n\n\n\n
1. what is a trade-off relationship?<\/h3>\n\n\n\n
\u3000A trade-off is a relationship in which one factor increases while the other decreases, like a seesaw on a playground, and the two factors cannot both increase and be compatible. For example, as shown in Figure 1, when the nonstructural carbohydrate (NSC) content per panicle of rice is low, the protein content in brown rice is high, and when the NSC content is high, the protein content in brown rice is low, indicating that a trade-off relationship exists between the two.<\/p>\n\n\n\n![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-32.png\")
<\/figure>\n\n\n\n2. why the trade-offs?<\/h3>\n\n\n\n
\u3000\u690d\u7269\u4f53\u5185\u3067\uff0c\u30bf\u30f3\u30d1\u30af\u8cea\u3068\u70ad\u6c34\u5316\u7269\u306e\u542b\u91cf\u304c\u30c8\u30ec\u30fc\u30c9\u30aa\u30d5\u306e\u95a2\u4fc2\u306b\u306a\u308b\u306e\u306f\uff0c\u690d\u7269\u4f53\u5185\u306e\u70ad\u6c34\u5316\u7269\u542b\u91cf (A) \u304c\uff0c\u5149\u5408\u6210\u306b\u3088\u308b\u70ad\u6c34\u5316\u7269\u751f\u7523\u91cf (B)\u3068\u5438\u53ce\u3055\u308c\u305f\u7a92\u7d20\u304c\u4f53\u5185\u3067\u30bf\u30f3\u30d1\u30af\u8cea\u306b\u5909\u63db\u3055\u308c\u308b\u3068\u304d\u306b\u6d88\u8cbb\u3055\u308c\u308b\u70ad\u6c34\u5316\u7269\u91cf (C) \u3068\u306e\u5dee\u3067\u6c7a\u5b9a\u3055\u308c\u308b\u304b\u3089\uff08A = B\u2212C\uff09\u3067\u3042\u308b\u3002
\u3000This can be well understood from the perspective of the GS-GOGAT system introduced in the previous issue. That is, plants that are given a lot of nitrogen from compost or chemical fertilizers absorb a lot of nitrogen, of course. When more nitrogen is absorbed, it is incorporated into the GS-GOGAT system and amino acid synthesis is activated, resulting in an increase in protein content.
\u3000\u3053\u306e\u6642\uff0c\u30a2\u30df\u30ce\u9178\u5408\u6210\u306e\u305f\u3081\u306e\u539f\u6599\u306f\uff0c\u6839\u304b\u3089\u5438\u53ce\u3059\u308b\u30a2\u30f3\u30e2\u30cb\u30a6\u30e0\u30a4\u30aa\u30f3\u3084\u785d\u9178\u30a4\u30aa\u30f3\u306e\u4ed6\u306b\uff0c\u3082\u3046\u4e00\u3064\u306e\u539f\u6599\u304c\u5fc5\u8981\u3060\u3063\u305f\u3053\u3068\u3092\u601d\u3044\u51fa\u3057\u3066\u307b\u3057\u3044\u3002\u305d\u308c\u304c\uff12\u2212\u30aa\u30ad\u30bd\u30b0\u30eb\u30bf\u30fc\u30eb\u9178\u3067\u3042\u308b\u3002\u30a2\u30df\u30ce\u9178\u5408\u6210\u3092\u6d3b\u767a\u5316\u3055\u305b\u308b\u306b\u306f\uff0c\u3053\u306e\uff12\u2212\u30aa\u30ad\u30bd\u30b0\u30eb\u30bf\u30fc\u30eb\u9178\u3092\u591a\u91cf\u306b\u4f9b\u7d66\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u3002\uff12\u2212\u30aa\u30ad\u30bd\u30b0\u30eb\u30bf\u30fc\u30eb\u9178\u306f\uff0c\u8449\u3067\u3064\u304f\u3089\u308c\u305f\u5149\u5408\u6210\u7523\u7269\u306e\u70ad\u6c34\u5316\u7269\u3092\uff0c\u690d\u7269\u306e\u547c\u5438\u4f5c\u7528\u3067\u5206\u89e3\u3059\u308b\u904e\u7a0b\u3067\u3067\u304d\u308b\u4e2d\u9593\u7523\u7269\u306e\u6709\u6a5f\u9178\u3067\u3042\u308b\u3002\u305d\u308c\u3086\u3048\uff0c\u3053\u306e\u6709\u6a5f\u9178\u3092\u591a\u91cf\u306b\u4f9b\u7d66\u3059\u308b\u306b\u306f\uff0c\u547c\u5438\u4f5c\u7528\u3092\u6d3b\u767a\u306b\u3057\u3066\u70ad\u6c34\u5316\u7269\u306e\u5206\u89e3\u3092\u591a\u304f\u3057\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002\u305d\u306e\u7d50\u679c\uff0c\u690d\u7269\u4f53\u5185\u306b\u6b8b\u308b\u70ad\u6c34\u5316\u7269\u91cf\u306f\u5fc5\u7136\u7684\u306b
\u5c11\u306a\u304f\u306a\u308b\u3002
\u3000Conversely, if only a small amount of nitrogen is provided, plants synthesize only a few amino acids and have low protein content. Since not much is used for amino acid synthesis, not much is needed for the intermediate products of carbohydrate breakdown by respiration. As a result, more carbohydrates are left over, resulting in a relatively high carbohydrate content. This is the main mechanism that causes the trade-off relationship between protein and carbohydrates in plants.<\/p>\n\n\n\n
Nitrogen fertilization and crop quality<\/h3>\n\n\n\n
\u3000The trade-off between protein and carbohydrate content in crops means that nitrogen fertilization has a significant effect on the carbohydrate content of crops. We would like to consider this relationship in terms of the eating quality of rice and the relationship between different cultivation methods and the taste of the crop.<\/p>\n\n\n\n
1) Protein content and eating quality of rice<\/h4>\n\n\n\n
\u3000\u30b3\u30e1\uff08\u7cbe\u7c73\uff09\u306e\u98df\u5473\u7dcf\u5408\u8a55\u4fa1\u306f\uff0c\u660e\u3089\u304b\u306b\u30bf\u30f3\u30d1\u30af\u8cea\u542b\u91cf\u304c\u4f4e\u3044\u307b\u3069\u9ad8\u3044\u8a55\u4fa1\u3092\u53d7\u3051\u308b\uff08\u56f3\uff12\uff09\u3002\u3053\u308c\u306f\uff0c\u4f4e\u30bf\u30f3\u30d1\u30af\u8cea\u542b\u91cf\u3067\u3042\u308b\u307b\u3069\u70ad\u6c34\u5316\u7269\uff08\u30c7\u30f3\u30d7\u30f3\uff09\u542b\u91cf\u304c\u9ad8\u307e\u308a\uff0c\u65e5\u672c\u4eba\u597d\u307f\u306e\u98df\u5473\u306b\u306a\u308b\u304b\u3089\u3067\u3042\u308b\u3002\u3057\u305f\u304c\u3063\u3066\uff0c\u30b3\u30e1\u306e\u98df\u5473\u3092\u826f\u304f\u3059\u308b\u305f\u3081\u306b\uff0c\u30a4\u30cd\u306e\u30bf\u30f3\u30d1\u30af\u8cea\u542b\u91cf\u3092\u5fc5\u8981\u4ee5\u4e0a\u306b\u9ad8\u3081\u306a\u3044\u7a92\u7d20\u306e\u80a5\u57f9\u7ba1\u7406\u304c\u6c42\u3081\u3089\u308c\u3066\u3044\u308b\u3002\u3057\u304b\u3057\uff0c\u4f4e\u30bf\u30f3\u30d1\u30af\u8cea\u542b\u91cf\u3092\u306d\u3089\u3046\u3042\u307e\u308a\uff0c\u7a92\u7d20\u65bd\u4e0e\u91cf\u3092\u5c11\u306a\u304f\u3057\u3059\u304e\u308b\u3068\u7384\u7c73\u53ce\u91cf\u304c\u4f4e\u4e0b\u3059\u308b\u3002\u3064\u307e\u308a\uff0c\u9ad8\u30c7\u30f3\u30d7\u30f3\u8cea\u306e\u826f\u98df\u5473\u7c73\u3092\u751f\u7523\u3059\u308b\u306e\u306f\uff0c\u98df\u5473\u3068\u53ce\u91cf\u306e\u30ae\u30ea\u30ae\u30ea\u306e\u30d0\u30e9\u30f3\u30b9\u3067\uff0c\u7a92\u7d20\u306e\u80a5\u57f9\u7ba1\u7406\u3092\u304a\u3053\u306a\u3046\u9ad8\u3044\u6280\u8853\u3092\u5fc5\u8981\u3068\u3057\u3066\u3044\u308b\u3002
\u3000However, the eating quality of rice (milled rice) is not only affected by protein content, but also by low amylose content, which constitutes the starch of rice. The amylose content of rice is more influenced by variety characteristics than by nitrogen fertilization. Therefore, good-tasting rice varieties are selected from breeding material that has characteristics that result in low amylose content in the rice.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-33.png\")
<\/figure><\/div>\n\n\n(2) Differences in cultivation methods and the taste of agricultural products<\/h4>\n\n\n\n
\u3000It is often pointed out that organically grown produce tastes better than conventionally grown produce (conventionally grown using chemical fertilizers and pesticides). Is this a general fact? This can also be explained in terms of the relationship with the amount of nitrogen applied.
\u3000Compost is used as the nutrient source for the crop in organic farming, while chemical fertilizer is used in conventional farming. Let us now consider a case in which crops are grown using these two sources of nutrients with the same amount of total nitrogen applied. Even if the amount of total nitrogen applied is the same for both sources, the amount of nitrogen in a form that is easily absorbed and utilized by the crop (inorganic nitrogen) is usually much higher with chemical fertilizer than with compost. This is because the nitrogen in compost contains organic nitrogen that cannot be immediately absorbed by the crop.
\u3000\u3044\u3044\u304b\u3048\u308b\u3068\u4f5c\u7269\u304b\u3089\u307f\u308c\u3070\uff0c\u4e0e\u3048\u3089\u308c\u305f\u5168\u7a92\u7d20\u91cf\u304c\u540c\u3058\u3067\u3082\uff0c\u3059\u3050\u306b\u5438\u53ce\u3067\u304d\u308b\u7121\u6a5f\u614b\u7a92\u7d20\u91cf\u306f\u6163\u884c\u683d\u57f9\u306e\u5316\u5b66\u80a5\u6599\u3067\u4e0e\u3048\u3089\u308c\u308b\u307b\u3046\u304c\uff0c\u6709\u6a5f\u683d\u57f9\u306e\u5806\u80a5\u3067\u4e0e\u3048\u3089\u308c\u305f\u5834\u5408\u3088\u308a\u591a\u3044\u3002\u305d\u3046\u3059\u308b\u3068\uff0c\u6163\u884c\u683d\u57f9\u306e\u307b\u3046\u304c\u6709\u6a5f\u683d\u57f9\u3088\u308a\u3082\u4f5c\u7269\u306e\u7a92\u7d20\u5438\u53ce\u91cf\u304c\u5897\u3048\u3066\uff0c\u30bf\u30f3\u30d1\u30af\u8cea\u542b\u91cf\u304c\u9ad8\u307e\u308a\uff0c\u305d\u306e\u7d50\u679c\uff0c\u70ad\u6c34\u5316\u7269\u542b\u91cf\u304c\u4f4e\u304f\u306a\u308b\u3002\u8fb2\u7523\u7269\u306e\u304a\u3044\u3057\u3055\u306f\uff0c\u7cd6\u985e\u3084\u30c7\u30f3\u30d7\u30f3\u306a\u3069\u70ad\u6c34\u5316\u7269\u542b\u91cf\u304c\u591a\u3044\u307b\u3069\u9ad8\u307e\u308b\u3068\u8003\u3048\u3089\u308c\u308b\u305f\u3081\uff0c\u7d50\u679c\u7684\u306b\u4e0e\u3048\u305f\u5168\u7a92\u7d20\u91cf\u304c\u540c\u3058\u306a\u306e\u306b\u6709\u6a5f\u8fb2\u7523\u7269\u306e\u307b\u3046\u304c\u304a\u3044\u3057\u3044\u3068\u3044\u3046\u8a55\u4fa1\u306b\u306a\u308b\u3002\u3057\u304b\u3057\uff0c\u305d\u308c\u306f\u683d\u57f9\u6cd5\u306e\u3061\u304c\u3044\u306b\u7531\u6765\u3059\u308b\u3053\u3068\u3067\u306f\u306a\u304f\uff0c\u7528\u3044\u305f\u990a\u5206\u6e90\u306b\u542b\u307e\u308c\u308b\u7121\u6a5f\u614b\u7a92\u7d20\u91cf\u306e\u3061\u304c\u3044\u304c\u4e3b\u306a\u539f\u56e0\u3067\u3042\u308b\u3002\u5316\u5b66\u80a5\u6599\u304b\u3089\u306e\u7a92\u7d20\u65bd\u4e0e\u91cf\u3092\uff0c\u5806\u80a5\u306b\u542b\u307e\u308c\u3066\u3044\u308b\u7121\u6a5f\u614b\u7a92\u7d20\u91cf\u3068\u7b49\u3057\u304f\u3059\u308c\u3070\uff0c\u4f5c\u7269\u306e\u7cd6\u985e\u306a\u3069\u306e\u70ad\u6c34\u5316\u7269\u542b\u91cf\u306b\uff0c\u4e21\u8005\u9593\u3067\u5927\u5dee\u306a\u304f\u306a\u308b\u3002
\u3000In other words, the fact that organic produce generally has lower protein content and higher carbohydrate content than conventional produce is not due to differences in cultivation methods, but rather to differences in the amount of inorganic nitrogen applied, even when the total nitrogen content fed is the same.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff14\u7ae0\u2212 \u571f\u306e\u3067\u304d\u65b9\u3068\u5730\u7403\u4e0a\u3067\u306e\u5f79\u5272
\u7b2c21\u56de \u300c\u571f\u306f\u751f\u304d\u3066\u3044\u308b\u300d\u3068\u3044\u308f\u308c\u308b\u306e\u306f\u306a\u305c\uff1f
\u2212\u571f\u306f\u751f\u304d\u7269\u306a\u306e\u304b<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u3000\uff15\u6708\u53f7 (\u7b2c750\u53f7)<\/p>\n\n\n\n
\u3000In this issue, we turn our attention to the soil itself. It is the soil that stably supports agriculture. The soil is the place where food that protects our lives is produced, and at the same time, it nurtures the lives of various living creatures. For this reason, it is often said that \"the soil is alive\" in awe of it. Why is this so?<\/p>\n\n\n\n
1. Is soil a living thing?<\/h3>\n\n\n\n
\u3000\u571f\u304c\u672c\u5f53\u306b\u300c\u751f\u304d\u3066\u3044\u308b\uff63 \uff0c\u3059\u306a\u308f\u3061\u751f\u304d\u7269\u306a\u306e\u304b\u3068\u6539\u3081\u3066\u554f\u3044\u305f\u3060\u3055\u308c\u308b\u3068\uff0c\u571f\u304c\u751f\u304d\u7269\u3067\u3042\u308b\u3068\u3044\u3046\u4eba\u306f\u591a\u304f\u306f\u306a\u3044\u3060\u308d\u3046\u3002
\u3000\u4e00\u822c\u7684\u306a\u6982\u5ff5\u3067\u751f\u304d\u7269\u3068\u3044\u3046\u306e\u306f\uff0c\u591a\u7d30\u80de\u751f\u7269\u3067\u3042\u308b\u3002\u305d\u306e\u591a\u7d30\u80de\u751f\u7269\u3067\u3042\u308b\u305f\u3081\u306b\u306f\uff0c\u2460\u5206\u5316\u3068\u751f\u9577\uff0c\u2461\u7e41\u6b96\u3068\u907a\u4f1d\uff0c\u2462\u74b0\u5883\u5909\u5316\u3078\u306e\u81ea\u5f8b\u6027\u3092\u6e80\u305f\u3059\u5fc5\u8981\u304c\u3042\u308b\uff08\u5ca1\u5cf6\uff0c1989) \u3002\u3057\u304b\u3057\uff0c\u571f\u306b\u4e21\u89aa\u304c\u3044\u3066\uff0c\u305d\u306e\u907a\u4f1d\u7684\u8981\u7d20\u3092\u5f15\u304d\u7d99\u3044\u3067\u5927\u304d\u304f\u306a\u308a\uff0c\u5b50\u4f9b\u3092\u80b2\u3066\uff0c\u6b7b\u3093\u3067\u3044\u304f\u3068\u306f\u3060\u308c\u3082\u8003\u3048\u306a\u3044\u3060\u308d\u3046\u3002\uff62\u571f\u306f\u751f\u304d\u3066\u3044\u308b\u300d\u3068\u3044\u3046\u306e\u306f\uff0c\u3042\u304f\u307e\u3067\u3082\uff0c\u571f\u3092\u8b6c\u55a9\uff08\u3072\u3086\uff09\u7684\u306b\u8868\u73fe\u3057\u3066\u3044\u308b\u306b\u3059\u304e\u306a\u3044\u3002\u571f\u3092\u656c\u611b\u3059\u308b\u3042\u307e\u308a\u306b\uff0c\u571f\u304c\u751f\u304d\u7269\u3067\u3042\u308b\u3068\u6df7\u540c\u3059\u308b\u306e\u306f\u3064\u3064\u3057\u3080\u3079\u304d\u3060\u308d\u3046\u3002
\u3000But even if it is a parable, the expression \"the soil is alive\" does not fail to capture our hearts. Why is that?<\/p>\n\n\n\n
2. soil has properties similar to the autonomy of living things<\/h3>\n\n\n\n
\u3000Soil has a property that gives a sense of the autonomy that living things have over their environment, i.e., the ability to maintain their own state of health in the face of external stimuli. This is the buffering power of soil.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-34.png\")
<\/figure><\/div>\n\n\n\u3000\u5177\u4f53\u7684\u306b\u571f\u306e\u7de9\u885d\u529b\u3092\u898b\u3066\u307f\u3088\u3046\u3002\u571f\u306b\u9178\u6027\u7269\u8cea\u3068\u3057\u3066\u5869\u9178\uff0c\u30a2\u30eb\u30ab\u30ea\u6027\u7269\u8cea\u3068\u3057\u3066\u6c34\u9178\u5316\u30ca\u30c8\u30ea\u30a6\u30e0\u3092\u305d\u308c\u305e\u308c\u6ef4\u4e0b\u3059\u308b\u3002\u3053\u308c\u306b\u3088\u3063\u3066\uff0c\u571f\u306f\u5916\u90e8\u304b\u3089\u523a\u6fc0\u304c\u52a0\u3048\u3089\u308c\u305f\u3053\u3068\u306b\u306a\u308b\u3002\u3053\u306e\u6642\uff0c\u56f3\uff11\u306b\u793a\u3057\u305f\u3088\u3046\u306b\uff0c\u7d14\u6c34\uff08H2<\/sub>O\uff09\u306e\u5834\u5408\uff0c\u307b\u3093\u306e\u308f\u305a\u304b\u306a\u6ef4\u4e0b\u91cf\u3067\uff0cpH\u304c\u9178\u6027\u5074\u306b\u3082\u30a2\u30eb\u30ab\u30ea\u6027\u5074\u306b\u3082\u5927\u304d\u304f\u5909\u5316\u3059\u308b\u3002\u4e00\u65b9\uff0c\u571fA\u3068\u571fB\u306e\u3069\u3061\u3089\u3082\uff0c\u7d14\u6c34\u3088\u308a\u5909\u5316\u306e\u5e45\u304c\u5c0f\u3055\u3044\u3002\u3064\u307e\u308a\uff0c\u571f\u306f\u7d14\u6c34\u3088\u308a\u7de9\u885d\u529b\u304c\u5927\u304d\u3044\u306e\u304c\u308f\u304b\u308b\u3002
\u3000\u305f\u3060\u3057\uff0c\u6709\u6a5f\u7269\u306e\u5c11\u306a\u3044\u571fA\u306f\uff0c\u6709\u6a5f\u7269\u306e\u591a\u3044\u571fB\u3088\u308a\u3082\u5909\u5316\u306e\u5e45\u304c\u5927\u304d\u304f\uff0c\u3057\u305f\u304c\u3063\u3066\u7de9\u885d\u529b\u306f\u5c0f\u3055\u3044\u3002\u571f\u306e\u6709\u6a5f\u7269\u306f\uff0c\u9178\u6027\u306e\u539f\u56e0\u3067\u3042\u308b\u6c34\u7d20\u30a4\u30aa\u30f3\uff08H+\uff09\u3084\u30a2\u30eb\u30ab\u30ea\u6027\u306e\u539f\u56e0\u3067\u3042\u308b\u6c34\u9178\u30a4\u30aa\u30f3\uff08OH\u2212\uff09\u3092\u9759\u96fb\u6c17\u7684\u306b\u4fdd\u6301\u3059\u308b\u80fd\u529b\u3092\u6301\u3064\uff08\u571f\u306e\u9759\u96fb\u6c17\u7684\u306a\u30a4\u30aa\u30f3\u4fdd\u6301\u80fd\u306b\u3064\u3044\u3066\u306f\uff0c\u6628\u5e74\u306e\uff12\u6708\u53f7\u306e\u7b2c\uff19\u56de\u3092\u53c2\u7167)\u3002\u3053\u306e\u305f\u3081\uff0c\u6709\u6a5f\u7269\u304c\u305d\u308c\u3089\u306e\u30a4\u30aa\u30f3\u3092\u4fdd\u6301\u3057\u3066\u52d5\u304d\u3092\u6291\u3048\uff0c\u5916\u754c\u304b\u3089\u306e\u523a\u6fc0\u3092\u3084\u308f\u3089\u3052\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u3002\u571fB\u306e\u307b\u3046\u304c\u571fA\u3088\u308a\u3082\u7de9\u885d\u529b\u304c\u5927\u304d\u3044\u306e\u306f\uff0c\u571f\u306e\u6709\u6a5f\u7269\u542b\u91cf\u306e\u9055\u3044\u306b\u57fa\u3065\u304f\u3002\u3053\u306e\u3088\u3046\u306a\u571f\u304c\u6301\u3064\u7de9\u885d\u529b\u306f\uff0c\u751f\u304d\u7269\u306e\u81ea\u5f8b\u6027\u3068\u3088\u304f\u4f3c\u3066\u3044\u308b\u3002
\u3000However, the buffering capacity of the soil is not the only reason why the soil is said to be \"alive. The activities of living creatures living in the soil are often invisible to our eyes, and appear to us as if they were performed by the soil itself. This is another major factor that makes us feel that the soil is alive.<\/p>\n\n\n\n\uff13\uff0e\u751f\u304d\u7269\u305f\u3061\u306e\u751f\u6d3b\u306e\u8a3c\u3057\u2212\u571f\u58cc\u547c\u5438<\/h3>\n\n\n\n
\u3000The fact that compost fed to the soil becomes nutrients for crops, and that leaves that fall on the soil in the fall and kitchen scraps disappear eventually if they are buried in the soil, are all the result of decomposition of organic matter by soil organisms.
\u3000\u571f\u306e\u751f\u304d\u7269\u305f\u3061\u304c\uff0c\u5806\u80a5\u3084\u843d\u3061\u8449\uff0c\u751f\u30b4\u30df\u306a\u3069\u306e\u6709\u6a5f\u7269\u3092\u5206\u89e3\u3059\u308b\u3068\uff0c\u5206\u89e3\u7523\u7269\u306e\u4e00\u3064\u3068\u3057\u3066\u4e8c\u9178\u5316\u70ad\u7d20\uff08CO2<\/sub>\uff09\u304c\u6392\u51fa\u3055\u308c\u308b\u3002\u3053\u306e\u69d8\u5b50\u306f\u52d5\u7269\u306e\u547c\u5438\u306b\u4f3c\u3066\u3044\u308b\u3053\u3068\u304b\u3089\uff0c\u300c\u571f\u58cc\u547c\u5438\u300d\u3068\u3044\u308f\u308c\u308b\u3002\u3042\u305f\u304b\u3082\u571f\u304c\u547c\u5438\u3057\u3066\u3044\u308b\u304b\u306e\u3088\u3046\u306a\u611f\u899a\u3067\u3042\u308b\u3002\u3057\u304b\u3057\u3053\u308c\u306f\uff0c\u3042\u304f\u307e\u3067\u3082\u571f\u306e\u4e2d\u3067\u751f\u6d3b\u3057\u3066\u3044\u308b\u751f\u304d\u7269\u305f\u3061\u306e\u6d3b\u52d5\u306e\u8a3c\u3057\u3067\u3042\u3063\u3066\uff0c\u571f\u81ea\u8eab\u304c\u547c\u5438\u3057\u3066\u3044\u308b\u308f\u3051\u3067\u306f\u306a\u3044\u3002<\/p>\n\n\n\n4. organic matter decomposition is a cooperative play among soil organisms<\/h3>\n\n\n\n
\u3000\u4e0a\u3067\u8ff0\u3079\u305f\u843d\u3061\u8449\u3092\u4f8b\u306b\uff0c\u571f\u306e\u751f\u304d\u7269\u305f\u3061\u304c\u6709\u6a5f\u7269\u3092\u5206\u89e3\u3059\u308b\u6642\u306e\uff0c\u307f\u3054\u3068\u306a\u9023\u4fc2\u30d7\u30ec\u30fc\u3092\u898b\u3066\u307f\u3088\u3046\uff08\u56f3\uff12) \u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-35.png\")
<\/figure><\/div>\n\n\n\u3000\u571f\u306e\u8868\u9762\u306b\u3042\u308b\u843d\u3061\u8449\uff08\u690d\u7269\u907a\u4f53\uff09\u306f\uff0c\u305d\u306e\u307e\u307e\u4e7e\u3044\u305f\u72b6\u614b\u3067\u306f\u5927\u304d\u304f\u5909\u5316\u3057\u306a\u3044\u3002\u3057\u304b\u3057\uff0c\u305d
\u308c\u304c\u3072\u3068\u305f\u3073\u96e8\u306b\u6253\u305f\u308c\u3066\u6fe1\u308c\u308b\u3068\uff0c\u305d\u3053\u306b\u307e\u305a\u30d0\u30af\u30c6\u30ea\u30a2\uff08\u7d30\u83cc\uff09\u3084\u30ab\u30d3\uff08\u7cf8\u72b6\u83cc\uff09\u304c\u3068\u308a\u3064\u304d\uff0c
\u3053\u306e\u690d\u7269\u907a\u4f53\u3092\u3042\u308b\u7a0b\u5ea6\u8edf\u3089\u304b\u304f\u3059\u308b\u3002
\u3000Then, large soil animals such as earthworms, borers, and sowbugs appear and feed on the plant remains, pulverizing them and dragging them and their remains into the soil. Medium-sized soil animals, such as mites and stoneflies, then take charge, feeding on the dragged organic matter and taking nutrients into their bodies, and excreting the unwanted material as feces.
\u3000Bacteria and fungi feed on the excreted feces and the remains of plants that have been dragged into the soil, eventually transforming them into carbon dioxide, water, and inorganic substances. The inorganic matter produced by this process is absorbed by the roots as nutrients for the plants growing there. Thus, a cycle of nutrients is established. Of course, the same mechanism applies to animal remains as it does to plants.
\u3000The various material changes that occur in the soil include changes involving soil organisms. Therefore, when we talk about material changes in the soil, if we blur the distinction between the function of the soil and the function of living creatures in the soil, we confuse the two.<\/p>\n\n\n\n
5. distinguish between the workings of the soil and the workings of living things.<\/h3>\n\n\n\n
\u3000\u571f\u306e\u50cd\u304d\u3068\u8868\u73fe\u3057\u3066\u3082\uff0c\u305d\u308c\u306f\u571f\u306b\u751f\u304d\u7269\u306e\u3088\u3046\u306a\u300c\u610f\u5fd7\uff1d\u5408\u76ee\u7684\u6027\u300d\u304c\u3042\u3063\u3066\uff0c\u571f\u81ea\u8eab\u306e\u610f\u5fd7\u304c\u80fd\u52d5\u7684\u306b\u50cd\u304f\u3053\u3068\u3092\u610f\u5473\u3057\u3066\u3044\u306a\u3044\u3002\uff62\u571f\u304c\u4f5c\u7269\u306b\u990a\u5206\u3092\u4f9b\u7d66\u3059\u308b\u300d\u3068\u3044\u3046\u8868\u73fe\u3082\u5b9f\u306f\u4e0d\u9069\u5207\u3067\uff0c\u571f\u81ea\u4f53\u304c\u4f5c\u7269\u3078\u610f\u56f3\u7684\u306b\u990a\u5206\u3092\u4f9b\u7d66\u3059\u308b\u3053\u3068\u306f\u306a\u3044\u3002\u571f\u306e\u4e2d\u306e\u6c34\uff08\u571f\u58cc\u6eb6\u6db2\uff09\u306b\u6eb6\u3051\u3066\u3044\u308b\u3055\u307e\u3056\u307e\u306a\u990a\u5206\u30a4\u30aa\u30f3\u306e\u4e2d\u304b\u3089\uff0c\u4f5c\u7269\u304c\u5fc5\u8981\u3068\u3059\u308b\u990a\u5206\uff0c\u4f8b\u3048\u3070\u967d\u30a4\u30aa\u30f3\u306e\u990a\u5206\u3092\u9078\u629e\u3057\u3066\u5438\u53ce\u3059\u308b\u3068\uff0c\u305d\u308c\u307e\u3067\u306e\u96fb\u6c17\u7684\u4e2d\u6027\u539f\u7406\uff08\u967d\u30a4\u30aa\u30f3\u3068\u9670\u30a4\u30aa\u30f3\u306e\u8377\u96fb\u91cf\u304c\u7b49\u3057\u3044\u72b6\u614b\uff09\u306e\u30d0\u30e9\u30f3\u30b9\u304c\u304f\u305a\u308c\u308b\u3002\u304f\u305a\u308c\u305f\u30d0\u30e9\u30f3\u30b9\u3092\u3082\u3068\u306e\u72b6\u614b\u306b\u623b\u3059\u3088\u3046\u306b\uff0c\u571f\u306e\u4e2d\u3067\u591a\u69d8\u306a\u53cd\u4f5c\u7528\u304c\u304f\u308a\u5e83\u3052\u3089\u308c\uff0c\u96fb\u6c17\u7684\u4e2d\u6027\u539f\u7406\u3092\u7dad\u6301\u3059\u308b\u305f\u3081\u306b\u967d\u30a4\u30aa\u30f3\u304c\u571f\u58cc\u6eb6\u6db2\u306b\u653e\u51fa\u3055\u308c\u308b\u3002\u3053\u308c\u304c\u300c\u571f\u304c\u4f5c\u7269\u306b\u990a\u5206\u3092\u4f9b\u7d66\u3059\u308b\u300d\u3068\u8868\u73fe\u3055\u308c\u308b\u73fe\u8c61\u3067\u3042\u308b\u3002\u3053\u306e\u53cd\u4f5c\u7528\u3082\u4e00\u5b9a\u306e\u539f\u7406(\u3053\u306e\u4f8b\u3067\u306f\u6eb6\u6db2\u3067\u306e\u96fb\u6c17\u7684\u4e2d\u6027\u539f\u7406\uff09\u306b\u3088\u3063\u3066\u5f8b\u305b\u3089\u308c\u3066\u304a\u308a\uff0c\u751f\u304d\u7269\u304c\u3082\u3064\u81ea\u7531\u306a\u610f\u5fd7\u304c\u306f\u3044\u308a\u8fbc\u3080\u4f59\u5730\u306f\u306a\u3044\u3002
\u3000I would like to understand the true meaning of the parable \"the soil is alive\" after distinguishing the function of the soil and the creatures in the soil.<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff14\u7ae0\u2212 \u571f\u306e\u3067\u304d\u65b9\u3068\u5730\u7403\u4e0a\u3067\u306e\u5f79\u5272
\u7b2c22\u56de\u3000\u5730\u7403\u4e0a\u306e\u751f\u547d\u3092\u80b2\u307f\uff0c
\u5730\u7403\u74b0\u5883\u3092\u4fdd\u5168\u3059\u308b\u571f\u306e\u5f79\u5272<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u3000\uff16\u6708\u53f7 (\u7b2c751\u53f7)<\/p>\n\n\n\n
\u3000\u524d\u56de\u306f\u571f\u306e\u4e2d\u306e\u751f\u304d\u7269\u306b\u3064\u3044\u3066\u304a\u8a71\u3057\u3057\u305f\u3002\u3057\u304b\u3057\uff0c\u571f\u306f\u571f\u306e\u751f\u304d\u7269\u3060\u3051\u306b\u751f\u6d3b\u306e\u5834\u3092\u63d0\u4f9b\u3057\u3066\u3044\u308b\u306e\u3067\u306f\u306a\u3044\u3002\u5730\u7403\u306e\u9678\u5730\u306b\u5b58\u5728\u3059\u308b\u751f\u547d\u306e\u3059\u3079\u3066\u306f\uff0c\u76f4\u63a5\u3042\u308b\u3044\u306f\u9593\u63a5\u7684\u306b\u571f\u306e\u6069\u6075\u3092\u53d7\u3051\u3066\u3044\u308b\u3002\u305d\u308c\u306f\uff0c\u571f\u3067\u751f\u80b2\u3059\u308b\u690d\u7269\u3092\u8d77\u70b9\u306b\uff0c\u5730\u7403\u4e0a\u3067\u306e\u300c\u6355\u98df\uff08\u98df\u3079\u308b) \u2212\u88ab\u98df\uff08\u98df\u3079\u3089\u308c\u308b)\u300d\u3068\u3044\u3046\u98df\u7269\u9023\u9396\u306b\u3088\u3063\u3066\uff0c\u591a\u304f\u306e\u751f\u547d\u304c\u990a\u308f\u308c\u3066\u3044\u308b\u3053\u3068\u304b\u3089\u7406\u89e3\u3067\u304d\u308b\u3002\u305d\u308c\u3060\u3051\u3067\u306a\u304f\uff0c\u9678\u4e0a\u751f\u7269\u306e\u751f\u6d3b\u74b0\u5883\u3068\u306a\u308b\u5730\u7403\u74b0\u5883\u306e\u4fdd\u5168\u306b\u3082\u5927\u304d\u306a\u5f79\u5272\u3092\u679c\u305f\u3057\u3066\u3044\u308b\u3002
\u3000In this article, I would like to consider these important functions of soil.<\/p>\n\n\n\n
1. three major functions of soil<\/h3>\n\n\n\n
\u3000\u571f\u306e\u6a5f\u80fd\u3092\u6982\u89b3\u3059\u308c\u3070\uff0c\u9053\u8def\u3084\u9244\u9053\uff0c\u5efa\u7269\u306a\u3069\u306e\u57fa\u76e4\uff0c\u5404\u7a2e\u306e\u5efa\u7bc9\u8cc7\u6750\u3084\u7aaf\u696d\u306e\u539f\u6599\uff0c\u666f\u89b3\u306e\u69cb\u6210\u8981\u56e0\u3068\u3044\u3063\u305f\u3053\u3068\u304c\u601d\u3044\u6d6e\u304b\u3076\u3002\u3057\u304b\u3057\uff0c\u305d\u308c\u4ee5\u4e0a\u306b\uff0c\u2460\u9678\u4e0a\u306e\u690d\u7269\u3092\u80b2\u3066\u308b\u6a5f\u80fd\uff08\u751f\u7523\u6a5f\u80fd) \uff0c\u2461\u6c34\u3092\u4fdd\u6301\u3059\u308b\u6a5f\u80fd\uff08\u4fdd\u6c34\u6a5f\u80fd) \uff0c\u2462\u6709\u6a5f\u7269\u3084\u5316\u5b66\u7269\u8cea\u3092\u5206\u89e3\u3057\u6d44\u5316\u3059\u308b\u6a5f\u80fd\uff08\u5206\u89e3\u6d44\u5316\u6a5f\u80fd\uff09\u3067\uff0c\u5730\u4e0a\u306e\u751f\u547d\u3092\u652f\u3048\u308b\u3068\u3044\u3046\u91cd\u8981\u306a\u6a5f\u80fd\u304c\u3042\u308b\u3002<\/p>\n\n\n\n
(1) Function of growing plants on land (production function)<\/h4>\n\n\n\n
\u3000Plants receive heat and light from the sun, carbon dioxide from the atmosphere, and water from the soil for photosynthesis. This plant is the starting point of food for at least all terrestrial organisms. The food of the creatures in the soil is also originally organic matter produced by plants. Carnivores are also able to eat meat because herbivores live on plants. Since the soil supports the growth of plants, the productive function of the soil is extremely important for terrestrial organisms.
\u3000\u571f\u3092\u5229\u7528\u305b\u305a\uff0c\u5149\uff0c\u65e5\u9577\uff0c\u6e29\u5ea6\u306a\u3069\u306e\u751f\u80b2\u74b0\u5883\u3092\u4eba\u5de5\u7684\u306b\u7ba1\u7406\u3057\u3066\u4f5c\u7269\u3092\u6c34\u8015\u306a\u3069\u3067\u683d\u57f9\u3059\u308b\u5834\u5408\u304c\u3042\u308b\u3002\u3053\u306e\u3088\u3046\u306a\u65bd\u8a2d\u3092\u690d\u7269\u5de5\u5834\u3068\u3044\u3046\u3053\u3068\u304c\u3042\u308b\uff08\u56f3\uff11) \u3002
\u3000These cultivation methods require large energy costs for facilities and machinery for nutrient management, as well as for heating, cooling, and lighting, and high maintenance and management costs, including labor. In addition, the spread of external pathogens and diseases during cultivation is much faster than with soil cultivation. Furthermore, it is unrealistic to leave food production to hydroponics, considering concerns about the sustainability of fossil energy. The dependence of terrestrial organisms on soil for food production is unlikely to change in the future.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-36.png\")
<\/figure><\/div>\n\n\n(2) Function to retain water (water retention function)<\/h4>\n\n\n\n
\u3000When the soil is covered with asphalt-paved urban streets and concrete buildings, much of the rainwater does not percolate into the soil, but instead flows directly into rivers through the sewage system. Under these conditions, when temporary heavy rains occur, small urban rivers overflow and cause damage. This is because the soil has lost its function of holding water.
\u3000\u571f\u306e\u4fdd\u6c34\u80fd\u529b\u306e\u4f4e\u4e0b\u306b\u8d77\u56e0\u3059\u308b\u73fe\u8c61\u306f\uff0c\u305f\u3068\u3048\u3070\uff0c\u68ee\u6797\u3092\u4f10\u63a1\u3057\u3066\u5207\u308a\u958b\u3044\u305f\u4e18\u9675\u5730\u306e\u5b85\u5730\u9020\u6210\u5730\u3067\u3082\u8a8d\u3081\u3089\u308c\u308b\u3002\u305d\u306e\u3088\u3046\u306a\u73fe\u5834\u3067\u306f\uff0c\u96e8\u6c34\u304c\u571f\u306e\u8868\u9762\u3092\u304b\u3051\u629c\u3051\uff0c\u8868\u571f\u3092\u524a\u308a\u306a\u304c\u3089\u6fc1\u6d41\u306b\u306a\u3063\u3066\u6cb3\u5ddd\u306b\u6d41\u308c\u8fbc\u3080\u3002\u571f\u7802\u5d29\u308c\u3082\u8d77\u304d\u3084\u3059\u3044\u3002
\u300021\u4e16\u7d00\u306f\u6c34\u554f\u984c\u306e\u4e16\u7d00\u3068\u3044\u308f\u308c\u308b\uff08\u30dd\u30b9\u30c6\u30eb\uff0c2000) \u3002\u8fb2\u5730\u306e\u98df\u6599\u751f\u7523\u3067\u3082\uff0c\u6de1\u6c34\u8cc7\u6e90\u304c\u5236\u9650\u56e0\u5b50\u306b\u306a\u3063\u3066\u5897\u7523\u306e\u671f\u5f85\u304c\u3082\u3066\u306a\u3044\u3002\u571f\u306e\u4fdd\u6c34\u80fd\u529b\u306e\u4f4e\u4e0b\u3060\u3051\u3067\u306a\u304f\uff0c\u5730\u4e0b\u306b\u8caf\u7559\u3055\u308c\u3066\u3044\u305f\u6c34\uff08\u5730\u4e0b\u5e2f\u6c34\u5c64\uff09\u306e\u904e\u5270\u5229\u7528\u3067\uff0c\u5e2f\u6c34\u5c64\u306e\u8caf\u6c34\u91cf\u304c\u6fc0\u6e1b\u3057\u3066\u3044\u308b\u305f\u3081\u3060\u3002\u571f\u306e\u4fdd\u6c34\u80fd\u529b\u306f\uff0c\u79c1\u305f\u3061\u4eba\u985e\u3092\u542b\u3080\u5730\u4e0a\u306e\u751f\u7269\u306e\u672a\u6765\u306b\u5927\u304d\u306a\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u3002<\/p>\n\n\n\n
(3) Decompose and purify organic matter and chemical substances (decomposition and purification function)<\/h4>\n\n\n\n
\u3000\u571f\u306e\u4e2d\u306e\u751f\u7269\u304c\uff0c\u52d5\u690d\u7269\u306e\u907a\u4f53\u3084\u52d5\u7269\u306e\u6392\u6cc4\u7269\u306a\u3069\u306e\u6709\u6a5f\u7269\u3092\u5206\u89e3\u3059\u308b\u3053\u3068\u306f\uff0c\u524d\u56de\u304a\u8a71\u3057\u3057\u305f\u3002\u3053\u306e\u6709\u6a5f\u7269\u306e\u5206\u89e3\u3067\u990a\u5206\u5faa\u74b0\u304c\u751f\u307f\u51fa\u3055\u308c\u308b\u3002
\u3000\u5404\u7a2e\u306e\u6709\u5bb3\u306a\u6709\u6a5f\u6027\u5ec3\u68c4\u7269\u306a\u3069\u3082\uff0c\u571f\u306e\u4e2d\u3067\u306e\u5206\u89e3\u904e\u7a0b\u3067\u6d44\u5316\u3055\u308c\u308b\u3002\u4eba\u5de5\u306e\u5316\u5b66\u7269\u8cea\uff0c\u305f\u3068\u3048\u3070\uff0c\u77f3\u6cb9\u6210\u5206\u3084\u30c8\u30ea\u30af\u30ed\u30ed\u30a8\u30c1\u30ec\u30f3\uff0c\u30dd\u30ea\u5869\u5316\u30d3\u30d5\u30a7\u30cb\u30fc\u30eb\uff08PCB\uff09\u3068\u3044\u3063\u305f\uff0c\u304b\u3064\u3066\u554f\u984c\u8996\u3055\u308c\u305f\u3044\u308f\u3086\u308b\u74b0\u5883\u30db\u30eb\u30e2\u30f3\u306e\u524d\u99c6\u7269\u8cea\u3067\u3042\u308b\uff0c\u6709\u6a5f\u5869\u7d20\u5316\u5408\u7269\u3092\u5206\u89e3\u3059\u308b\u5fae\u751f\u7269\u3082\u571f\u306b\u751f\u606f\u3059\u308b\uff08\u5185\u5c71\uff0c1999) \u3002\u5fae\u751f\u7269\u306e\u6c5a\u67d3\u7269\u8cea\u5206\u89e3\u80fd\u529b\u3092\u5229\u7528\u3057\u3066\u6c5a\u67d3\u7269\u8cea\u3092\u6d44\u5316\u3057\uff0c\u74b0\u5883\u3092\u4fee\u5fa9\u3059\u308b\u3053\u3068\u3092\u30d0\u30a4\u30aa\u30ec\u30e1\u30c7\u30a3\u30a8\u30fc\u30b7\u30e7\u30f3\uff08\u751f\u7269\u7684\u4fee\u5fa9\uff09\u3068\u3044\u3044\uff0c\u5b89\u5168\u306a\u74b0\u5883\u6c5a\u67d3\u4fee\u5fa9\u5bfe\u7b56\u3068\u3057\u3066\u6ce8\u76ee\u3055\u308c\u3066\u3044\u308b\u3002
\u3000However, the function of decomposition and purification of organic matter is not a function of the soil itself but a function derived from the biological activity of the soil.<\/p>\n\n\n\n
2. soil supports and preserves the global environment<\/h3>\n\n\n\n
\u3000The Earth's environment is maintained by the smooth circulation of heat, energy, water, chemicals, and other materials between the atmosphere, biosphere, hydrosphere, and geosphere that make up the Earth's surface. Most of the transfer of materials and energy between these spheres takes place through the soil, which is the contact surface (interface).
\u3000The rate of movement of matter and energy in the soil controls the speed of that movement. The physical, chemical, and biological properties and functions of soil can change the flow of water, heat, and materials from a rapid state to a gentle state, and in some cases, they can be stored in the soil to inhibit the flow itself. The ability of soil to soften the rate of movement of materials (buffering capacity) is a fundamental factor in ensuring the harmonious and smooth circulation of materials and energy on the earth.
\u3000Since the 20th century, human activities have expanded on an unprecedented scale, adversely affecting the global environment. Unprincipled deforestation to expand arable land, massive consumption of fossil fuels to increase productivity, and other human activities have caused the flow of materials and energy to exceed the control of the soil. The resulting changes in the global environment have had adverse effects such as global warming, depletion of the ozone layer, desertification and salinization of the soil, soil erosion, water pollution, and reduction of biodiversity.<\/p>\n\n\n\n
3. soil functions are threatened by 10<\/h3>\n\n\n\n
\u3000\u304b\u3051\u304c\u3048\u306e\u306a\u3044\u571f\u304c\uff0c\u4eba\u9593\u6d3b\u52d5\u306b\u8d77\u56e0\u3057\u3066\u305d\u306e\u751f\u7523\u6a5f\u80fd\u3092\u5931\u3063\u3066\u3057\u307e\u3046\u73fe\u8c61\u3092\u571f\u306e\u52a3\u5316\u3068\u3044\u3046\u3002\u52a3\u5316\u3057\u305f\u571f\u5730\u9762\u7a4d\u306f\uff0c20\u4e16\u7d00\u672b\u3067\uff0c\u5730\u4e0a\u306e\u690d\u751f\u5730\u306e17\uff05\uff0c20\u5104ha\u306b\u3082\u9054\u3057\u3066\u3044\u308b\uff08\u56fd\u9023\u74b0\u5883\u8a08\u753b\uff0c1997) \u3002
\u30002015\u5e74\u306b\u516c\u8868\u3055\u308c\u305f\u4e16\u754c\u571f\u58cc\u8cc7\u6e90\u5831\u544a\u66f8\uff08FAO\u3068\u571f\u306b\u95a2\u3059\u308b\u653f\u5e9c\u9593\u30d1\u30cd\u30eb\uff1dITPS\uff0c2015\uff09\u306b\u3088\u308c\u3070\uff0c\u571f\u306e\u6a5f\u80fd\u306b\u5bfe\u3057\u306610\u306e\u6df1\u523b\u306a\u8105\u5a01\u304c\u3042\u308b\u3068\u3044\u3046\u3002\u305d\u306e\u8105\u5a01\u3092\u5f37\u3055\u306e\u9806\u306b\u4e26\u3079\u308b\u3068\uff0c\u2460\u571f\u58cc\u4fb5\u98df\uff0c\u2461\u6709\u6a5f\u70ad\u7d20\u306e\u5909\u5316\uff0c\u2462\u990a\u5206\u306e\u4e0d\u5747\u8861\uff0c\u2463\u5869\u985e\u96c6\u7a4d\u3068\u30ca\u30c8\u30ea\u30a6\u30e0\u5316\uff0c\u2464\u571f\u58cc\u88ab\u8986\uff08\u30b3\u30f3\u30af\u30ea\u30fc\u30c8\u3084\u30a2\u30b9\u30d5\u30a1\u30eb\u30c8\u306a\u3069\u3067\u571f\u3092\u88ab\u8986\u3057\u3066\uff0c\u900f\u6c34\u6027\u3092\u963b\u5bb3\u3059\u308b\u3053\u3068) \uff0c\u2465\u571f\u306e\u751f\u7269\u591a\u69d8\u6027\u306e\u6e1b\u5c11\uff0c\u2466\u571f\u58cc\u6c5a\u67d3\uff0c\u2467\u9178\u6027\u5316\uff0c\u2468\u571f\u58cc\u5727\u5bc6\uff0c\u2469\u6e5b\u6c34\uff08\u3068\u304f\u306b\u597d\u6c17\u7684\u72b6\u614b\u304b\u3089\u6e5b\u6c34\u72b6\u614b\u306b\u5909\u308f\u308b\u5834\u5408\uff09\u3067\u3042\u308b\u3002
\u3000\u571f\u306e\u6a5f\u80fd\u304c\uff0c\u69d8\u3005\u306a\u8105\u5a01\u3084\u4eba\u9593\u6d3b\u52d5\u3067\u596a\u308f\u308c\u3066\u3044\u308b\u3002\u3057\u304b\u3057\uff0c\u8fb2\u5bb6\u306e\u9069\u5207\u306a\u7ba1\u7406\u304c\u8fb2\u5730\u306e\u571f\u306e\u6a5f\u80fd\u3092\u7dad\u6301\u3057\u3066\u3044\u308b\u306e\u3082\u307e\u305f\uff0c\u4e8b\u5b9f\u3067\u3042\u308b\uff08\u56f3\uff12) \u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-37.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff14\u7ae0\u2212 \u571f\u306e\u3067\u304d\u65b9\u3068\u5730\u7403\u4e0a\u3067\u306e\u5f79\u5272
\u7b2c23\u56de\u3000\u539f\u59cb\u5730\u7403\u306b\u571f\u306f\u306a\u304b\u3063\u305f
\u2212\u3053\u3046\u3057\u3066\u5730\u7403\u306b\u571f\u304c\u8a95\u751f\u3057\u305f<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u3000\uff17\u6708\u53f7 (\u7b2c752\u53f7)<\/p>\n\n\n\n
\u3000All this time we have been talking about soil. This was based on the assumption that soil is all around us. However, has soil been on the earth since the birth of the earth 4.6 billion years ago? The answer is no.
\u3000In this issue, I would like to return to the primitive earth and reflect on the story of how soil came to be on the earth and how it supports life.<\/p>\n\n\n\n
1. the earth before the appearance of soil<\/h3>\n\n\n\n
\u3000\u4eca\uff0c\u79c1\u9054\u306e\u8db3\u3082\u3068\u306b\u306f\u571f\u304c\u3042\u308b\u3002\u3057\u304b\u3057\uff0c\u90fd\u4f1a\u306e\u30a2\u30b9\u30d5\u30a1\u30eb\u30c8\u8217\u88c5\u3055\u308c\u305f\u4e2d\u3067\u751f\u6d3b\u3059\u308b\u4eba\u306b\u306f\uff0c\u571f\u304c\u3042\u308b\u3053\u3068\u3055\u3048\u5fd8\u308c\u3066\u3044\u308b\u304b\u3082\u77e5\u308c\u306a\u3044\u3002\u305d\u308c\u3067\u3082\u90ca\u5916\u306b\u51fa\u3066\u5e83\u304c\u308b\u8fb2\u5730\u3084\u91ce\u5c71\u3092\u773a\u3081\u308b\u3068\uff0c\u305d\u3053\u306b\u571f\u306e\u3042\u308b\u98a8\u666f\u306b\u5de1\u308a\u4f1a\u3048\u308b\u3002\u305d\u308c\u304c\u65e5\u5e38\u3067\u3042\u308b\u3002\u305d\u306e\u571f\u306a\u306e\u3060\u304c\uff0c\u73fe\u5728\u306e\u79c1\u305f\u3061\u304c\u8003\u3048\u308b\u571f\u306b\u4f3c\u305f\u7269\u8cea\uff08\u521d\u671f\u306e\u571f\uff09\u304c\u3053\u306e\u5730\u7403\u4e0a\u306b\u767b\u5834\u3057\u305f\u306e\u306f\uff0c\u4eca\u304b\u3089\uff16\u5104\u5e74\u307b\u3069\u524d\u3068\u8003\u3048\u3089\u308c\u3066\u3044\u308b\u3002\u305d\u3057\u3066\uff0c\u79c1\u9054\u304c\u30a4\u30e1\u30fc\u30b8\u3059\u308b\u571f\u304c\u767b\u5834\u3057\u305f\u306e\u306f\uff13\u5104\u5e74\u307b\u3069\u524d\u3067\u3042\u308b\u3002\u5730\u7403\u4e0a\u306b\u571f\u304c\u8a95\u751f\u3059\u308b\u306b\u306f\uff0c\u4ee5\u4e0b\u306b\u8ff0\u3079\u308b\u3088\u3046\u306a\u30c9\u30e9\u30de\u304c\u3042\u3063\u305f\uff08\u56f3\uff11) \u3002
\u30004.6 billion years ago, asteroids in the universe collided with each other, accumulating energy and gradually expanding to form the Earth. Immediately after its birth, the earth was in a state of bare magma, with temperatures reaching over 1,000\u00b0C. Later, as asteroid impacts decreased, the magma cooled over time. Later, as the number of asteroid impacts decreased, the magma cooled with the passage of time. When the surface temperature reached about 300\u00b0C, water vapor fell to the ground in torrential rain. This became the ocean. This was about 4 billion years ago. This ocean was hot and highly acidic, with hydrochloric acid as its main ingredient. This is because the rain dissolved the gases emitted from the magma.
\u3000At that time, the atmosphere was 97% carbon dioxide (carbon dioxide gas). Carbon dioxide could not dissolve into the strongly acidic ocean. However, as the dissolved components from the rocks gradually neutralized the oceans, carbon dioxide gradually dissolved into the oceans, further neutralizing the acidic oceans.
\u3000Life was first found in the sea. This is because the sun's ultraviolet rays are harmful to living organisms, and the only place where they could avoid these rays was in the sea. This is thought to have occurred approximately 3.8 billion years ago. It seems that life began with bacteria that could grow in anaerobic conditions, that is, in the absence of oxygen.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-39.png\")
<\/figure><\/div>\n\n\n2. birth of life and formation of the ozone layer<\/h3>\n\n\n\n
\u300020\u5104\u5e74\u524d\u307e\u3067\u6642\u304c\u3059\u3059\u3080\u3068\uff0c\u6d77\u6c34\u4e2d\u306e\u751f\u547d\u306e\u306a\u304b\u306b\u5149\u5408\u6210\u306e\u6a5f\u80fd\u3092\u8eab\u306b\u3064\u3051\u308b\u7d30\u83cc\u304c\u73fe\u308c\u305f\u3002\u305d\u308c\u304c\u30b7\u30a2\u30ce\u30d0\u30af\u30c6\u30ea\u30a2\uff08\u30e9\u30f3\u85fb\uff0c\u304b\u3064\u3066\u306f\u690d\u7269\u306e\u4ef2\u9593\u3068\u5206\u985e\u3055\u308c\u3066\u3044\u305f\u304c\uff0c\u73fe\u5728\u306f\u7d30\u83cc\u3068\u3057\u3066\u6271\u308f\u308c\u308b\uff09\u3067\u3042\u308b\u3002\u30b7\u30a2\u30ce\u30d0\u30af\u30c6\u30ea\u30a2\u306f\uff0c\u6d77\u6c34\u4e2d\u306e\u7121\u6a5f\u7269\uff08\u30df\u30cd\u30e9\u30eb\uff09\u3068\u70ad\u9178\u30ab\u30eb\u30b7\u30a6\u30e0\u3068\u3092\u53cd\u5fdc\u3055\u305b\u3066\u5c64\u72b6\u306b\u5806\u7a4d\u3059\u308b\u30b9\u30c8\u30ed\u30de\u30c8\u30e9\u30a4\u30c8\u3068\u547c\u3070\u308c\u308b\u5ca9\u77f3\u72b6\u7269\u8cea\u3092\u3064\u304f\u308a\u3060\u3057\u305f\u3002\u305d\u306e\u8868\u9762\u306b\u81ea\u8eab\u3082\u751f\u304d\u6b8b\u308a\uff0c\u5149\u5408\u6210\u3092\u304a\u3053\u306a\u3063\u3066\u9178\u7d20\u306e\u653e\u51fa\u3092\u7d9a\u3051\u305f\u3002\u305d\u308c\u306b\u3088\u3063\u3066\uff0c\u5927\u6c17\u306b\u9178\u7d20\u304c\u5f90\u3005\u306b\u542b\u307e\u308c\u308b\u3088\u3046\u306b\u306a\u3063\u305f\u3002\u305d\u3057\u3066\u4eca\u304b\u3089\u304a\u3088\u305d\uff16\u5104\u5e74\u524d\uff0c\u5927\u6c17\u306e\u9178\u7d20\u6fc3\u5ea6\u304c2\uff05\u306b\u307e\u3067\u5897\u3048\u308b\u3068\uff0c\u30aa\u30be\u30f3\u5c64\u304c\u5927\u6c17\u4e2d\u306b\u3067\u304d\u306f\u3058\u3081\u305f\uff08\u56f3\uff11) \u3002
\u3000The ozone layer blocked ultraviolet radiation from the sun. This blockage of ultraviolet radiation, which is harmful to living organisms, has allowed marine life to come ashore. The first organisms to come ashore were lichens. Lichens are organisms in which algae (cyanobacteria, green algae, etc.) coexist inside a structure made of fungal mycelium. The photosynthetic products produced by the algae are used by the fungi to support their life, allowing them to grow even under conditions with limited nutrient sources.<\/p>\n\n\n\n
3. birth of soil<\/h3>\n\n\n\n
\u3000\u305d\u306e\u5730\u8863\u985e\u304c\u9678\u4e0a\u306e\u5ca9\u77f3\u306b\u3068\u308a\u3064\u304d\uff0c\u5ca9\u77f3\u3092\u5909\u8cea\u3055\u305b\u3066\u3044\u3063\u305f\u3002\u540c\u6642\u306b\uff0c\u5730\u8863\u985e\u81ea\u8eab\u304c\u6b7b\u306c\u3068\uff0c\u305d\u306e\u907a\u4f53\u304c\u6709\u6a5f\u7269\u3068\u306a\u3063\u3066\u6b21\u4e16\u4ee3\u306e\u6804\u990a\u5206\u306b\u306a\u308b\u3060\u3051\u3067\u306a\u304f\uff0c\u5909\u8cea\u3057\u305f\u5ca9\u77f3\u306b\u3082\u6df7\u3058\u308a\u5408\u3063\u3066\uff0c\u5730\u7403\u4e0a\u306b\u521d\u671f\u306e\u571f\u304c\u3067\u304d\u306f\u3058\u3081\u305f\u3002\u304a\u3088\u305d\uff16\u5104\u5e74\u524d\u306e\u3053\u3068\u3067\u3042\u308b\u3002\u305d\u306e\u5f8c\uff0c\u3053\u306e\u4f5c\u7528\u304c\u7e70\u308a\u8fd4\u3055\u308c\u308b\u3053\u3068\u3067\uff0c\u3086\u3063\u304f\u308a\u3068\u571f\u304c\u3064\u304f\u3089\u308c\u3066\u3044\u3063\u305f\u3002
\u3000\u3053\u3046\u3057\u3066\uff0c\u304a\u3088\u305d\uff13\u5104\u5e74\u524d\u306b\u306f\uff0c\u5730\u7403\u4e0a\u306b\u571f\u304c\u3067\u304d\u3066\u3044\u305f\u3068\u8003\u3048\u3089\u308c\u3066\u3044\u308b\u3002\u305d\u308c\u306f\uff0c\u5f53\u6642\u306e\u9678\u4e0a\u306b\u306f\u5c01\u5370\u6728\uff0c\u8606\u6728\u306a\u3069\u306e\u5de8\u5927\u306a\u30b7\u30c0\u690d\u7269\u306e\u68ee\u6797\u304c\u3067\u304d\uff0c\u4e21\u751f\u985e\uff0c\u6606\u866b\u985e\u304c\u51fa\u73fe\u3057\u305f\u3053\u3068\u304b\u3089\u3046\u304b\u304c\u3044\u77e5\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u3002\u305d\u308c\u3089\u304c\u73fe\u5728\u306e\u5316\u77f3\u71c3\u6599\u3092\u63d0\u4f9b\u3057\u3066\u3044\u308b\uff08\u56f3\uff11) \u3002
\u3000It took a long journey for soil to be formed by the organisms that came to life on the earth. That path was completed at that time, and it has not ended, but continues to the present day. At first glance, the soil appears to be immovable. However, as an extension of this enormous change over time, the soil is still changing to harmonize with its environment.<\/p>\n\n\n\n
4. the earth's \"skin\" supports terrestrial life<\/h3>\n\n\n\n
\u3000The earth is in the exquisite position of being the third closest to the sun. Too close to the sun and water evaporates and disappears. If it is farther from the sun, it will freeze. The exquisite position means that there was enough distance between the sun and the earth for water to exist stably. This water and the oxygen in the atmosphere made it possible for life to survive on Earth.
\u3000\u5730\u7403\u306f\u534a\u5f84\u304a\u3088\u305d6400km\u306e\u307b\u307c\u7403\u4f53\u3067\u3042\u308b(\u56f3\uff12) \u3002\u3053\u306e\u7403\u4f53\u306e\u4e2d\u5fc3\u90e8\u304c\u6838\u3067\uff0c\u305d\u306e\u5916\u5074\u304c\u30de\u30f3\u30c8\u30eb\uff0c\u305d\u3057\u3066\u30de\u30f3\u30c8\u30eb\u306e\u5916\u5074\u306b\u5730\u6bbb\u304c\u3042\u308b\u3002\u9678\u5730\u306f\uff0c\u5730\u7403\u306e\u8868\u9762\u7a4d\u306e30\uff05\u7a0b\u5ea6\u306b\u3059\u304e\u306a\u3044\u3002\u9678\u5730\u306e\u5730\u8868\u304b\u308930\u301c40km\u306e\u539a\u3055\u3067\u8986\u308f\u308c\u308b\u90e8\u5206\u304c\u5927\u9678\u5730\u6bbb\u3067\u3042\u308b\u3002\u571f\u306f\u5927\u9678\u5730\u6bbb\u306e\u8868\u9762\u306e\u307b\u3093\u306e\u6570cm\u304b\u3089\u305b\u3044\u305c\u3044\u6570m\uff0c\u5168\u5730\u7403\u3092\u5e73\u5747\u3059\u308b\u306818cm\u306e\u539a\u307f\u3057\u304b\u306a\u3044\u3068\u3044\u3046\uff08\u967d\uff0c1994) \u3002\u3053\u306e\u539a\u307f\u306f\uff0c\u5730\u7403\u306e\u534a\u5f84\u306e1000\u4e07\u5206\u306e1\u306b\u3059\u304e\u306a\u3044\u3002\u4eba\u306e\u76ae\u819a\u306f\u5e73\u5747\u3059\u308b\u30682mm\uff0c\u8eab\u95772m\u306e\u4eba\u306e1000\u5206\u306e1\u3067\u3042\u308b\u3002\u3064\u307e\u308a\u571f\u306f\uff0c\u5730\u7403\u898f\u6a21\u3067\u307f\u308b\u3068\u4eba\u306e\u76ae\u819a\u3088\u308a\u3082\u3055\u3089\u306b\u8584\u3044\uff0c\u304b\u3059\u304b\u306a\u76ae\u819a\u306b\u3059\u304e\u306a\u3044\u3002\u5730\u7403\u3092\u56f3\uff12\u306e\u3088\u3046\u306b\u8868\u73fe\u3059\u308b\u3068\uff0c18cm\u306e\u539a\u307f\u306f\uff0c\u56f3\u306b\u793a\u3057\u305f\u5186\u306e\u5916\u5468\u7dda\u306e\u592a\u3055\u3067\u3082\u539a\u3059\u304e\uff0c\u56f3\u793a\u3059\u3089\u3067\u304d\u306a\u3044\u307b\u3069\u306e\u8584\u3055\u3067\u3042\u308b\u3002
\u3000Plants grow in the soil, which is a faint skin of the earth, and microorganisms and animals live on it, and much of our food is produced from the soil. The soil, which is only a small part of the earth as a whole, supports the life of all terrestrial life on earth.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-40.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff14\u7ae0\u2212 \u571f\u306e\u3067\u304d\u65b9\u3068\u5730\u7403\u4e0a\u3067\u306e\u5f79\u5272
\u7b2c24\u56de\u3000\u571f\u306f\u74b0\u5883\u306e\u7523\u7269\u3067\u3042\u308b
\u2212\u98a8\u5316\u3068\u751f\u7269\u306e\u4f5c\u7528\u304c\u5ca9\u77f3\u304b\u3089\u571f\u3092\u3064\u304f\u308b<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74 8\/9\u6708\u5408\u4f75\u53f7 (\u7b2c753\u53f7)<\/p>\n\n\n\n
\u3000About 600 million years ago, 4 billion years after the birth of the earth 4.6 billion years ago, something like soil (early soil) was formed, and about 300 million years ago, the soil we imagine was formed on the earth. In the last issue, I told you the story of the formation of soil. This time, I would like to talk about how soil is created by the environment.<\/p>\n\n\n\n
1. change in perception of soil<\/h3>\n\n\n\n
\u3000\u571f\u306f\uff0c\u3053\u308c\u307e\u3067\u3069\u306e\u3088\u3046\u306b\u8a8d\u8b58\u3055\u308c\u3066\u304d\u305f\u306e\u3060\u308d\u3046\u304b\u300219\u4e16\u7d00\u307e\u3067\uff0c\u571f\u306f\u5ca9\u77f3\u304c\u98a8\u5316\u3057\u305f\u5730\u6bbb\u306e\u8868\u5c64\u306b\u3042\u308b\u3084\u308f\u3089\u304b\u3044\u7269\u4f53\uff0c\u3068\u3044\u3046\u304f\u3089\u3044\u306b\u3057\u304b\u8003\u3048\u3089\u308c\u3066\u3044\u306a\u304b\u3063\u305f\u3002\u3053\u306e\u8003\u3048\u65b9\u3092\uff0c\u571f\u306f\u74b0\u5883\u306b\u3088\u3063\u3066\u3064\u304f\u3089\u308c\u308b\u3068\u3044\u3046\u898b\u65b9\u306b\u8ee2\u63db\u3055\u305b\u305f\u306e\u304c\uff0c\u30ed\u30b7\u30a2\u306e\u82e5\u304d\u5730\u8cea\u5b66\u8005\u3067\uff0c\u5f8c\u306b\u571f\u58cc\u5b66\u306e\u7956\u3068\u3044\u308f\u308c\u308b\u30c9\u30af\u30c1\u30e3\u30fc\u30a8\u30d5\uff081846\u22121903\uff09\u3067\u3042\u308b\u3002
\u3000He believed that soil is formed by the interaction of various factors such as rocks, which are the raw materials of soil, climate, plants and animals, and topography, and that the formed soil changes with time. He also argued that soil, like animals and plants, is one of the components of nature and that soil is a product of the environment. Let us look at this idea in detail below.<\/p>\n\n\n\n
\uff12\uff0e\u571f\u3092\u3064\u304f\u308b\u4e8c\u3064\u306e\u8981\u56e0\u98a8\u5316\u3068\u751f\u7269\u306e\u4f5c\u7528<\/h3>\n\n\n\n
\u308f\u304c\u56fd\u3067\u306f\uff0c\u706b\u5c71\u7070\u3092\u539f\u6599\u3068\u3059\u308b\u571f (\u9ed2\u30dc\u30af\u571f)\u304c\u5e83\u304f\u5206\u5e03\u3057\u3066\u3044\u308b\u3002\u3057\u304b\u3057\uff0c\u4e16\u754c\u7684\u306b\u307f\u308b\u3068\u9ed2\u30dc\u30af\u571f\u306f\u4f8b\u5916\u7684\u306a\u571f\u3067\uff0c\u4e00\u822c\u7684\u306a\u571f\u306e\u539f\u6599\u306f\u5ca9\u77f3\u3067\u3042\u308b\u3002\u3053\u306e\u539f\u6599\u3068\u306a\u308b\u5ca9\u77f3\u3092\u6bcd\u5ca9\u3068\u3044\u3046\u3002\u305d\u306e\u6bcd\u5ca9\u304b\u3089\u571f\u304c\u3067\u304d\u308b\u306b\u306f\uff0c\u5ca9\u77f3\u304c\u7d30\u304b\u304f\u7815\u304b\u308c\u308b\u4f5c\u7528\uff08\u98a8\u5316\uff09\u3068\uff0c\u305d\u306e\u7815\u304b\u308c\u305f\u5ca9\u77f3\u306b\u751f\u7269\u304c\u50cd\u304d\u304b\u3051\u3066\u571f\u3092\u3064\u304f\u308a\u3042\u3052\u3066\u3044\u304f\u4f5c\u7528\u306e\u4e8c\u3064\u304c\u5fc5\u8981\u3067\u3042\u308b\uff08\u56f3\uff11) \u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-41.png\")
<\/figure><\/div>\n\n\n\u3000\u571f\u304c\u3067\u304d\u308b\u305f\u3081\u306b\u307e\u305a\u5fc5\u8981\u306a\u3053\u3068\u306f\uff0c\u98a8\u5316\u306b\u3088\u3063\u3066\u6bcd\u5ca9\u304c\u7d30\u304b\u304f\u7815\u304b\u308c\u305f\u7269\u8cea\uff08\u3053\u308c\u3092\u571f\u306e\u6bcd\u6750\u3068\u3044\u3046\uff09\u306e\u8868\u9762\u306b\uff0c\u5148\u6708\u53f7\u8ff0\u3079\u305f\u5730\u8863\u985e\u3084\u5fae\u751f\u7269\u305f\u3061\u304c\u3068\u308a\u3064\u304f\u3053\u3068\u3067\u3042\u308b\u3002\u305d\u3057\u3066\u305d\u308c\u3089\u304c\u305d\u3053\u3067\u306e\u751f\u6d3b\u3092\u307e\u3063\u3068\u3046\u3057\u3066\u6b7b\u306c\u3068\uff0c\u305d\u306e\u907a\u4f53\u306f\u5225\u306e\u5fae\u751f\u7269\u306b\u3088\u3063\u3066\u5206\u89e3\u3055\u308c\u308b\u3002\u305d\u306e\u5206\u89e3\u7523\u7269\u304c\u690d\u7269\u306e\u990a\u5206\u306b\u306a\u308b\u3002\u3053\u306e\u990a\u5206\u304c\u84c4\u7a4d\u3059\u308b\u3068\uff0c\u690d\u7269\u304c\u751f\u6d3b\u3067\u304d\u308b\u74b0\u5883\u304c\u5099\u308f\u308a\uff0c\u305d\u3053\u3078\u3088\u308a\u9ad8\u7b49\u306a\u690d\u7269\u3067\u3042\u308b\u30b3\u30b1\u985e\u3084\u30a4\u30cd\u79d1\u306e\u8349\u306a\u3069\u304c\u4fb5\u5165\u3059\u308b\u3002\u30b3\u30b1\u3084\u8349\u304c\u5165\u3063\u3066\u304f\u308b\u3068\uff0c\u3053\u308c\u3089\u306e\u907a\u4f53\u304c\u5fae\u751f\u7269\u306b\u5206\u89e3\u3055\u308c\u3066\u990a\u5206\u304c\u3055\u3089\u306b\u5897\u3048\u308b\u3002\u305d\u3046\u3059\u308b\u3068\uff0c\u571f\u306e\u52d5\u7269\uff08\u30df\u30df\u30ba\u306a\u3069\uff09\u304c\u4f4f\u3081\u308b\u3088\u3046\u306b\u306a\u308b\u3002\u571f\u306e\u52d5\u7269\u305f\u3061\u306f\uff0c\u690d\u7269\u907a\u4f53\u306e\u5206\u89e3\u7523\u7269\u3068\u3057\u3066\u6bcd\u6750\u306b\u84c4\u7a4d\u3057\u3066\u3044\u305f\u6709\u6a5f\u7269\u3092\u30a8\u30b5\u306b\u3057\u3066\u751f\u304d\uff0c\u6b7b\u3093\u3067\u3044\u304f\u3002\u305d\u306e\u7d50\u679c\uff0c\u6bcd\u6750\u306e\u8868\u9762\u306f\u990a\u5206\u304c\u3055\u3089\u306b\u8c4a\u304b\u306b\u306a\u3063\u3066\u3044\u304f\u3002\u3053\u3046\u3057\u3066\uff0c\u3088\u308a\u9ad8\u5ea6\u306a\u690d\u7269\u304c\u751f\u6d3b\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308b\u3002\u305d\u3057\u3066\u305d\u306e\u9ad8\u7b49\u690d\u7269\u304c\u67af\u308c\u3066\u907a\u4f53\u306b\u306a\u308b\u3068\u3044\u3046\u3053\u3068\u304c\u304f\u308a\u8fd4\u3055\u308c\u308b\u3068\uff0c\u5f90\u3005\u306b\u6bcd\u6750\u306e\u8868\u9762\u306b\uff0c\u6709\u6a5f\u7269\u3068\u6bcd\u6750\u3068\u304c\u6df7\u3058\u308a\u5408\u3063\u305f\u9ed2\u3044\u8272\u3092\u5e2f\u3073\u305f\u571f\u306e\u8868\u5c64\u304c\u3067\u304d\u3042\u304c\u3063\u3066\u3044\u304f\u3002
\u3000The action that creates soil in this way is the result of the action of living organisms on the parent material. No matter how much a rock is weathered and crushed into small pieces, soil cannot be created without the presence and action of living organisms.<\/p>\n\n\n\n
3. the function of soil-building organisms is affected by the environment<\/h3>\n\n\n\n
\u3000The workings of the organisms that make up the soil are closely linked to the environment. This is because the types of organisms and their activity are greatly influenced by the climate.
\u3000In cold regions at high latitudes, the amount of organic matter added to the soil is low because plant growth is poor. However, because of the cold weather, decomposition of organic matter by microorganisms does not progress, and organic matter accumulates, resulting in dark soil with a darker color, as indicated by the organic matter. On the other hand, in low-latitude tropical rainforest areas, the amount of organic matter added to the soil is much higher than in colder regions because of vigorous plant growth. However, because of the higher temperatures, the decomposition of organic matter by microorganisms is faster, and organic matter is less likely to accumulate in the soil. Therefore, the soil in this region does not darken, and a reddish-brown color is produced.
\u3000Soil is formed and changes within the limits of given environmental conditions, not at will. This is why Dochkiaev describes soil as \"a product of the environment,\" and asserts that \"soil is not some mechanical, accidental, lifeless mixture; on the contrary, it is a natural history formation (a historical natural body) determined and governed by independent and fixed laws. In other words, given certain environmental conditions, the same soil will be produced if the base material is the same. However, even if the base material is the same, if the environmental conditions are different, the resulting soil will be different. The environment creates the soil.
\u3000\u6539\u3081\u3066\u4e16\u754c\u306e\u571f\u3092\u773a\u3081\u308b\u3068\uff08\u56f3\uff12) \uff0c\u571f\u306f\u5730\u7403\u306e\u7def\u5ea6\u306b\u6cbf\u3063\u3066\u5e2f\u72b6\u306b\u5206\u5e03\u3057\u3066\u3044\u308b\u3088\u3046\u306b\u898b\u3048\u308b\u3002\u7def\u5ea6\u306b\u5fdc\u3058\u3066\u6c17\u5019\u304c\u5927\u304d\u304f\u5909\u5316\u3057\uff0c\u305d\u306e\u5909\u5316\u306b\u5bfe\u5fdc\u3057\u305f\u751f\u7269\u306e\u7570\u306a\u308b\u50cd\u304d\u3067\u571f\u304c\u3067\u304d\u308b\u304b\u3089\u3067\u3042\u308b\u3002\u5de8\u8996\u7684\u306b\u307f\u308c\u3070\uff0c\u30c9\u30af\u30c1\u30e3\u30fc\u30a8\u30d5\u306e\u6307\u6458\u3069\u304a\u308a\uff0c\uff62\u571f\u306f\u74b0\u5883\u306e\u7523\u7269\u3067\u3042\u308b\u300d\u3053\u3068\u304c\u5b9f\u611f\u3067\u304d\u308b\u3002
\u3000The moon is devoid of life. Therefore, the biological processes necessary to create soil do not work. Therefore, there are rocks on the moon, but no soil. Because the earth is at a perfect distance from the sun, the atmosphere and water can exist, and organisms were born. Thanks to the work of these organisms, soil was created and agriculture began.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-42.jpg\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff15\u7ae0\u2212 \u8fb2\u696d\u306b\u8d77\u56e0\u3059\u308b\u74b0\u5883\u554f\u984c
\u7b2c25\u56de\u3000\u8fb2\u696d\u304c\u74b0\u5883\u7834\u58ca\u306e\u59cb\u307e\u308a
\u2212\u4eba\u9593\u6d3b\u52d5\u3068\u74b0\u5883\u3068\u306e\u95a2\u308f\u308a\u2212<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u300010\u6708\u53f7 (\u7b2c754\u53f7)<\/p>\n\n\n\n
\u3000Soil is created in a given environment through the work of the living organisms present there. This is the idea of the Russian soil scientist Dokuchaev, which I mentioned last month. As if to prove the correctness of this idea, from a macroscopic viewpoint, the world's soil is distributed along latitudinal zones corresponding to climatic changes. This is because climatic conditions have a great influence on the environment. We can truly feel that soil is a product of the environment.
\u3000This month, we will consider the relationship between the soil and the environment in terms of human activities, especially in terms of food production.<\/p>\n\n\n\n
1. the beginning of agriculture<\/h3>\n\n\n\n
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\u3000\u3053\u306e\u8fb2\u696d\u306e\u59cb\u307e\u308a\u306f\uff0c\u4eba\u304c\u81ea\u7136\u306b\u50cd\u304d\u304b\u3051\u3066\u571f\u5730\u3092\u5207\u308a\u62d3\u304d\uff0c\u305d\u3053\u306e\u571f\u3067\u98df\u3079\u3082\u306e\u3092\u683d\u57f9\u3059\u308b\u3068\u3044\u3046\u7a4d\u6975\u7684\u306a\u884c\u70ba\u3060\u3063\u305f\u3002\u305d\u308c\u306f\u4eba\u306e\u66ae\u3089\u3057\u3092\u5909\u5316\u3055\u305b\u305f\u3002\u3082\u3061\u308d\u3093\uff0c\u5f53\u6642\u306f\u81ea\u7136\u74b0\u5883\u306e\u307b\u3046\u304c\u5727\u5012\u7684\u306a\u529b\u3067\u4eba\u985e\u3092\u652f\u914d\u3057\u3066\u3044\u305f\u306f\u305a\u3060\u3002\u3057\u304b\u3057\uff0c\u4eba\u985e\u304c\u81ea\u7136\u306b\u6311\u6226\u3057\u305f\u6700\u521d\u306e\u51fa\u6765\u4e8b\u3060\u3063\u305f\u3002\u4e0e\u3048\u3089\u308c\u3066\u3044\u308b\u81ea\u7136\u74b0\u5883\u306b\u4eba\u306e\u624b\u3092\u52a0\u3048\u308b\u3068\u3044\u3046\u610f\u5473\u3067\u306f\uff0c\u74b0\u5883\u7834\u58ca\u306e\u306f\u3058\u307e\u308a\u3068\u3082\u7406\u89e3\u3067\u304d\u308b\uff08\u56f3\uff11) \u3002\u4eba\u9593\u6d3b\u52d5\u304c\u81ea\u7136\u74b0\u5883\u306e\u529b\u3088\u308a\u5f31\u3044\u6bb5\u968e\u3067\u306f\uff0c\u305d\u308c\u306f\u5927\u304d\u306a\u554f\u984c\u3068\u306a\u3089\u306a\u304b\u3063\u305f\u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-42.png\")
<\/figure><\/div>\n\n\n2. the center of human productive activity changed with the Industrial Revolution<\/h3>\n\n\n\n
\u3000However, when human activities become so active that they alter the natural environment, the altered natural environment cannot be restored. It was the Industrial Revolution that reversed the power relationship between human productive activities and nature.
\u300018\u4e16\u7d00\u5f8c\u534a\u304b\u308919\u4e16\u7d00\u306e\u524d\u534a\u306b\u304b\u3051\u3066\uff0c\u30a4\u30ae\u30ea\u30b9\u3067\u8d77\u3053\u3063\u305f\u7523\u696d\u9769\u547d\u306f\u4eba\u306e\u66ae\u3089\u3057\u3092\u4e00\u5909\u3055\u305b\u305f\u3002\u77f3\u70ad\u3092\u4f7f\u3063\u305f\u30a8\u30cd\u30eb\u30ae\u30fc\u8ee2\u63db\u3067\u6a5f\u68b0\u5316\u3059\u308b\u3053\u3068\u3092\u77e5\u3063\u305f\u5f53\u6642\u306e\u4eba\u305f\u3061\u306f\uff0c\u305d\u308c\u3092\u5229\u7528\u3057\u3066\u7d4c\u6e08\u6d3b\u52d5\u3092\u5927\u304d\u304f\u767a\u5c55\u3055\u305b\u305f\u3002\u305d\u308c\u307e\u3067\uff0c\u8fb2\u696d\u304c\u4eba\u9593\u306e\u751f\u7523\u6d3b\u52d5\u306e\u4e2d\u5fc3\u3067\u3042\u3063\u305f\u3002\u3057\u304b\u3057\uff0c\u7523\u696d\u9769\u547d\u306f\u305d\u308c\u3092\u5de5\u696d\u306b\u8ee2\u63db\u3055\u305b\u3066\u3057\u307e\u3063\u305f\u3002
\u3000Around the same time as the Industrial Revolution, the hyper-intensive Norfolk farming system was established. This led to a dramatic increase in agricultural productivity. This was a factor in increasing the rural population. Ironically, the increased rural population was sent to the cities as factory workers, which were needed in the Industrial Revolution. This led to a rapid increase in the urban population. The total population of pre-industrial England in 1801 was 8.32 million. The urban population was 3.66 million, or 44% of the total population. Eighty years later, in 1881, after the Industrial Revolution, the total population had tripled to 25.91 million, and the urban population had quintupled to 17.28 million, 67% of the total population.<\/p>\n\n\n\n
3. commercialization of food has changed the value of food<\/h3>\n\n\n\n
\u3000Both to increase the population and to provide food for the increased population, it is necessary to increase the production of food. The increase in the production of food was demanded in the rural areas. This situation further led to the enclosure of farmland. At the same time, farm management, in which capitalists who leased large tracts of land from landlords hired peasants as wage laborers to turn the food they produced into a commodity and make a profit from its sale, emerged and expanded. Thus, with the Industrial Revolution, communal subsistence management disappeared from English farming villages. This transformation of rural society that occurred with the Industrial Revolution in England in the latter half of the 18th century is called the Agricultural Revolution.
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4. criticizing plundering agriculture without nutrient cycle, Liebig<\/h3>\n\n\n\n
\u3000It was Liebig, who lived during the Industrial Revolution, who strongly criticized this waste of resources, especially agriculture, which only takes crop nutrients from the soil and does not replenish them, thereby reducing the fertility of the soil.
\u3000\u7523\u696d\u9769\u547d\u5f8c\u306e\u30a4\u30ae\u30ea\u30b9\u3067\u306f\uff0c\u8fb2\u6751\u3068\u90fd\u5e02\u3067\u5206\u696d\u304c\u9032\u3093\u3060\u3002\u4e3b\u98df\u306e\u7a40\u7269\u306f\u8fb2\u6751\u3067\u751f\u7523\u3057\uff0c\u305d\u306e\u7a40\u7269\u3092\u6d88\u8cbb\u3059\u308b\u306e\u304c\u30ed\u30f3\u30c9\u30f3\u306a\u3069\u306e\u90fd\u5e02\u52b4\u50cd\u8005\u3068\u3044\u3046\u6642\u4ee3\u306b\u306a\u3063\u3066\u3044\u3063\u305f\u3002\u8fb2\u6751\u306e\u8fb2\u5730\u306e\u571f\u304b\u3089\u5438\u53ce\u3055\u308c\u305f\u4f5c\u7269\u990a\u5206\u306f\uff0c\u53ce\u7a6b\u7269\u3067\u3042\u308b\u7a40\u7269\u306b\u542b\u307e\u308c\u305f\u307e\u307e\u90fd\u5e02\u306b\u904b\u3070\u308c\u308b\u3002\u90fd\u5e02\u52b4\u50cd\u8005\u304c\u98df\u3079\u305f\u7a40\u7269\u306b\u542b\u307e\u308c\u308b\u4f5c\u7269\u990a\u5206\u306e\u4e00\u90e8\u306f\u52b4\u50cd\u8005\u306e\u6392\u6cc4\u7269\u306b\u79fb\u884c\u3057\uff0c\u305d\u306e\u6392\u6cc4\u7269\u306f\u591c\uff0c\u7a93\u8fba\u304b\u3089\u8857\u8def\u306b\u6295\u3052\u6368\u3066\u3089\u308c\u305f\u3002\u5f53\u6642\u306e\u90fd\u5e02\u306f\u4e0b\u6c34\u9053\u304c\u6574\u5099\u3055\u308c\u3066\u3044\u306a\u304b\u3063\u305f\u305f\u3081\uff0c\u305d\u308c\u3089\u306f\u96e8\u306b\u6d41\u3055\u308c\uff0c\u30ed\u30f3\u30c9\u30f3\u3067\u306f\u76f4\u63a5\u30c6\u30e0\u30ba\u5ddd\u306b\u904b\u3070\u308c\u305f\u3002\u3053\u306e\u305f\u3081\uff0c\u30c6\u30e0\u30ba\u5ddd\u306f\u5f37\u70c8\u306a\u60aa\u81ed\u306b\u307e\u307f\u308c\uff0c\u4e0d\u885b\u751f\u304d\u308f\u307e\u308a\u306a\u304b\u3063\u305f\u3002\u3053\u3046\u3057\u3066\uff0c\u8fb2\u6751\u306e\u571f\u306b\u3042\u3063\u305f\u4f5c\u7269\u990a\u5206\u306f\uff0c\u5143\u306e\u8fb2\u5730\u306e\u571f\u3078\u623b\u308c\u306a\u304f\u306a\u3063\u305f\u3002\u30ea\u30fc\u30d3\u30d2\u306f\uff0c\u305d\u3046\u3057\u305f\u571f\u306e\u990a\u5206\u3092\u6d88\u8cbb\u3059\u308b\u3060\u3051\u306e\u300c\u7565\u596a\u8fb2\u696d\u300d\u3067\u306f\u5b89\u5b9a\u3057\u305f\u98df\u6599\u4f9b\u7d66\u304c\u3067\u304d\u306a\u3044\u3068\u5f37\u304f\u6279\u5224\u3057\uff0c\u8fb2\u696d\u306e\u6301\u7d9a\u6027\u306b\u6700\u3082\u91cd\u8981\u306a\u3053\u3068\u306f\u990a\u5206\u5faa\u74b0\u3067\u3042\u308b\u3053\u3068\u3092\u5f37\u8abf\u3057\u305f\u3002
\u3000\u305d\u306e\u30ea\u30fc\u30d3\u30d2\u304c\u990a\u5206\u5faa\u74b0\u306e\u7406\u60f3\u3068\u3057\u305f\u306e\u304c\u65e5\u672c\u306e\u8fb2\u696d\u3060\u3063\u305f\u3002\u6c5f\u6238\u6642\u4ee3\u306e17\u4e16\u7d00\u4ee5\u964d\u306b\u306f\uff0c\u5f53\u6642\u306e\u4e16\u754c\u7684\u5927\u90fd\u5e02\u6c5f\u6238\u306e\u6d88\u8cbb\u8005\u306e\u3057\u5c3f\u304c\uff0c\u5f7c\u3089\u306b\u98df\u6599\u3092\u63d0\u4f9b\u3059\u308b\u5468\u8fba\u8fb2\u6751\u306e\u8fb2\u5730\u306b\u9084\u5143\u3055\u308c\u308b\u7d4c\u8def\u304c\u3057\u3063\u304b\u308a\u3068\u78ba\u7acb\u3055\u308c\u3066\u3044\u305f\u304b\u3089\u3067\u3042\u308b\uff08\u30ea\u30fc\u30d3\u30d2\u30fb\u5409\u7530\u8a33\uff0c2007) \u3002
\u3000\u7523\u696d\u9769\u547d\u4ee5\u964d\uff0c\u4eba\u3005\u306e\u66ae\u3089\u3057\u306f\u8c4a\u304b\u3067\u4fbf\u5229\u306b\u306a\u308a\uff0c\u4eba\u9593\u6d3b\u52d5\u304c\u307e\u3059\u307e\u3059\u5927\u304d\u304f\u306a\u3063\u3066\u3044\u3063\u305f\uff08\u56f3\uff12) \u3002\u81ea\u7136\u304b\u3089\u9810\u304b\u3063\u305f\u793e\u4f1a\u5171\u6709\u306e\u8ca1\u7523\u3067\u3042\u308b\u306f\u305a\u306e\u571f\u304b\u3089\uff0c\u8cc7\u6e90\u3092\u52dd\u624b\u6c17\u307e\u307e\u306b\u5229\u7528\u3057\u3066\u4f7f\u3044\u6368\u3066\u308b\u3068\u3044\u3046\u5229\u5df1\u7684\u306a\u7d4c\u6e08\u6d3b\u52d5\u304c\u5927\u304d\u306a\u6d41\u308c\u3068\u306a\u3063\u3066\u3057\u307e\u3063\u305f\u3002\u73fe\u5728\u3067\u306f\uff0c\u305d\u3046\u3057\u305f\u3053\u3068\u3067\uff0c\u8fb2\u696d\u81ea\u8eab\u304c\u74b0\u5883\u6c5a\u67d3\u6e90\u3068\u306a\u3063\u3066\u3057\u307e\u3046\u3068\u3044\u3046\u554f\u984c\u307e\u3067\u767a\u751f\u3057\u3066\u3044\u308b\u3002\u5177\u4f53\u7684\u306b\u3069\u306e\u3088\u3046\u306a\u554f\u984c\u304c\u3042\u308b\u306e\u304b\uff0c\u305d\u308c\u3092\u6765\u6708\u53f7\u4ee5\u964d\u3067\u898b\u3066\u307f\u3088\u3046\u3068\u601d\u3046\u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-43.png\")
<\/figure><\/div>\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff15\u7ae0\u2212 \u8fb2\u696d\u306b\u8d77\u56e0\u3059\u308b\u74b0\u5883\u554f\u984c
\u7b2c26\u56de\u3000\u8fb2\u696d\u3068\u74b0\u5883\u554f\u984c\u2212\u305d\u306e\uff11
\u308f\u304c\u56fd\u306e\u7a92\u7d20\u5faa\u74b0\u306e\u554f\u984c\u70b9<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u300011\u6708\u53f7 (\u7b2c755\u53f7)<\/p>\n\n\n\n
\u3000The beginning of agriculture was the first human challenge to nature. In the sense of adding human intervention to the natural environment, it can be said to be the beginning of environmental destruction. Later, after the Industrial Revolution, human activities became so active that they altered the natural environment. Agriculture is no exception.
\u3000In many countries today, environmental pollution originating from agriculture is a problem. When the amount of nutrients applied to agricultural land exceeds the nutrient holding capacity of the soil, the excess nutrients flow into the groundwater, rivers, and air in the surrounding environment, causing environmental pollution. This month, we will consider the relationship between agriculture and environmental pollution.
\u3000The first issue is unique to our country, which has a low food self-sufficiency rate.<\/p>\n\n\n\n
Changes in Japan's food self-sufficiency rate<\/h3>\n\n\n\n
\u3000In 1960, the Japanese government made two major cabinet decisions. The first was to accelerate economic growth through the Income Doubling Plan, and the second was to enact the Basic Agricultural Law. In 1960, Japan's food self-sufficiency rate (hereafter referred to as the calorie-based total calorific value of food supply) was 79%. Since then, however, Japan's food self-sufficiency rate has continued to decline, stagnating at 38 to 39% since 2010. The target for food self-sufficiency is 45% by 2030. Achievement of this goal is in jeopardy.
\u3000\u904e\u53bb60\u5e74\u9593\u306b\u308f\u305f\u3063\u3066\u308f\u304c\u56fd\u306e\u98df\u6599\u81ea\u7d66\u7387\u3092\u4f4e\u4e0b\u3055\u305b\u305f\u4e3b\u306a\u8981\u56e0\u306f\uff0c\u98df\u6599\u3092\u56fd\u5185\u3067\u307e\u304b\u306a\u3046\u3068\u3044\u3046\u57fa\u672c\u59ff\u52e2\u304c\u7dad\u6301\u3055\u308c\u306a\u304b\u3063\u305f\u3053\u3068\uff0c\u3055\u3089\u306b\u98df\u6599\u306e\u6d88\u8cbb\u5f62\u614b\u304c\u5909\u5316\u3057\u305f\u3053\u3068\u306b\u3042\u308b\u3002
\u3000\u4f8b\u3048\u3070\uff0c1965\u5e74\u5ea6\u30682021\u5e74\u5ea6\u306e56\u5e74\u9593\u3067\u6bd4\u8f03\u3059\u308b\u3068\uff0c\uff11\u4eba\uff11\u65e5\u5f53\u305f\u308a\u306e\u5404\u54c1\u76ee\u306e\u4f9b\u7d66\u71b1\u91cf\u3092\u5408\u8a08\u3057\u305f\u7dcf\u4f9b\u7d66\u71b1\u91cf\u306f\uff0c1965\u5e74\u5ea6\u304c2,459kcal\u3067\uff0c2021\u5e74\u5ea6\u306f\u3084\u3084\u5c11\u306a\u304f\u306a\u3063\u30662,256kcal\u3060\u3063\u305f\uff08\u56f3\uff11) \u3002\u3068\u3053\u308d\u304c\uff0c\u3053\u306e56\u5e74\u9593\u3067\u7c73\u306e\u6d88\u8cbb\u306f\u5927\u304d\u304f\u6e1b\u5c11\u3057\uff08\u4f9b\u7d66\u71b1\u91cf\u306e\u6e1b\u5c11)\uff0c\u305d\u306e\u6e1b\u5c11\u306f\u755c\u7523\u7269\uff08\u8089\u985e\uff0c\u9d8f\u5375\uff0c\u4e73\u88fd\u54c1\u306a\u3069\uff09\u3068\u6cb9\u8102\u985e(\u5927\u8c46\u6cb9\uff0c\u83dc\u7a2e\u6cb9\u306a\u3069\uff09\u306e\u6d88\u8cbb\u62e1\u5927\uff08\u4f9b\u7d66\u71b1\u91cf\u306e\u5897\u52a0\uff09\u3067\u76f8\u6bba\u3055\u308c\u3066\u3044\u308b\uff08\u56f3\uff11) \u3002\u3055\u3089\u306b\uff0c\u7dcf\u4f9b\u7d66\u71b1\u91cf\u306b\u5360\u3081\u308b\u5272\u5408\u306f56\u5e74\u9593\u3067\u5927\u304d\u306a\u5909\u5316\u304c\u306a\u3044\u306b\u3082\u304b\u304b\u308f\u3089\u305a\uff0c\u4f9b\u7d66\u71b1\u91cf\u306e\u81ea\u7d66\u7387\u304c\u5927\u304d\u304f\u4f4e\u4e0b\u3057\u305f\u54c1\u76ee\u3068\u3057\u3066\u679c\u5b9f\uff0c\u9b5a\u4ecb\u985e\uff0c\u5c0f\u9ea6\uff0c\u5927\u8c46\uff0c\u91ce\u83dc\uff0c\u305d\u3057\u3066\u300c\u305d\u306e\u4ed6\u300d\u306b\u533a\u5206\u3055\u308c\u308b\u54c1\u76ee\u304c\u3042\u308b\uff08\u56f3\uff11) \u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-44.png\")
<\/figure><\/div>\n\n\n\u3000\u3053\u3046\u3057\u305f\u98df\u6599\u306e\u6d88\u8cbb\u5f62\u614b\u306e\u5909\u5316\u3084\u54c1\u76ee\u5225\u306e\u81ea\u7d66\u7387\u306e\u4f4e\u4e0b\u306f\uff0c\u56fd\u6c11\u306e\u98df\u50be\u5411\u304c\u3054\u306f\u3093\u3068\u9b5a\u3068\u3044\u3046\u300c\u548c\u98a8\u300d\u304b\u3089\uff0c\u30d1\u30f3\u3084\u30d1\u30b9\u30bf\uff0c\u4e73\u8089\u88fd\u54c1\u3068\u3044\u3046\uff62\u6d0b\u98a8\u300d\u3078\u5909\u5316\u3057\u305f\u3053\u3068\u306b\u8d77\u56e0\u3059\u308b\u3002\u305f\u3060\u3057\uff0c\u3053\u306e\u98df\u6599\u306e\u6d88\u8cbb\u5f62\u614b\u306e\u5909\u5316\u306f\uff0c\u305d\u308c\u304c\u56fd\u6c11\u306e\u5358\u306a\u308b\u55dc\u597d\u306e\u5909\u5316\u3084\uff0c\u6240\u5f97\u306e\u5897\u52a0\u3068\u3044\u3063\u305f\u300c\u6210\u308a\u884c\u304d\u300d\u306e\u7d50\u679c\u3068\u306f\u8003\u3048\u306b\u304f\u3044\u3002\u3080\u3057\u308d\uff0c\u7b2c\u4e8c\u6b21\u4e16\u754c\u5927\u6226\u5f8c\u306e\u30a2\u30e1\u30ea\u30ab\u306e\u4f59\u5270\u8fb2\u7523\u7269\u8f38\u51fa\u6226\u7565\u306b\u547c\u5fdc\u3057\u305f\uff0c\u308f\u304c\u56fd\u306e\u653f\u7b56\u7684\u8a98\u5c0e\u306e\u7d50\u679c\u3068\u898b\u308b\u3079\u304d\u3060\u308d\u3046\uff08\u67cf\uff0c2012) \u3002<\/p>\n\n\n\n
Food production, consumption and nitrogen cycle in Japan<\/h3>\n\n\n\n
\u3000\u98df\u6599\u81ea\u7d66\u7387\u306e\u4f4e\u3055\u306f\uff0c\u3044\u3044\u304b\u3048\u308b\u3068\u5916\u56fd\u306e\u571f\u306b\u3042\u3063\u305f\u990a\u5206\u304c\u4f5c\u7269\u306b\u5438\u53ce\u3055\u308c\uff0c\u305d\u308c\u304c\u542b\u307e\u308c\u305f\u307e\u307e\u8f38\u5165\u98df\u6599\u3068\u306a\u3063\u3066\u591a\u91cf\u306b\u308f\u304c\u56fd\u306b\u6301\u3061\u8fbc\u307e\u308c\u3066\u3044\u308b\u3053\u3068\u3092\u610f\u5473\u3059\u308b\u3002\u306a\u304b\u3067\u3082\u7a92\u7d20\uff08N\uff09\u306f\uff0c\u6b21\u56de\u3067\u8ff0\u3079\u308b\u3088\u3046\u306b\uff0c\u74b0\u5883\u306b\u60aa\u5f71\u97ff\u3092\u4e0e\u3048\u3084\u3059\u3044\u3002\u305d\u306e\u308f\u304c\u56fd\u3067\u306eN\u5faa\u74b0\u91cf\u304c\uff0c\u81ea\u7d66\u7387\u306e\u4f4e\u4e0b\u306b\u3088\u3063\u3066\u3069\u3046\u5909\u5316\u3057\u305f\u304b\u3092\uff0c\u30c7\u30fc\u30bf\u304c\u5831\u544a\u3055\u308c\u3066\u3044\u308b1961\u5e74\u30682005\u5e74\u3067\u6bd4\u8f03\u3057\u3066\u307f\u308b\uff08\u56f3\uff12) \u3002<\/p>\n\n\n\n
(1) N circulating volume in 1961<\/h4>\n\n\n\n
\u3000\u98df\u6599\u81ea\u7d66\u7387\u304c78\uff05\u3060\u3063\u305f1961\u5e74\uff0c\u8f38\u5165\u3055\u308c\u305fN\u306f\uff0c\u4f5c\u7269\u304b\u308914\u4e07\u30c8\u30f3\uff0c\u30d7\u30ed\u30c6\u30a4\u30f3\u30df\u30fc\u30eb\u304b\u30892\u4e07\u30c8\u30f3\u3067\uff0c\u5e74\u9593\u308f\u305a\u304b\u306b16\u4e07\u30c8\u30f3\u3060\u3063\u305f\u3002\u4e00\u65b9\uff0c\u8fb2\u8015\u5730\u306b\u4f9b\u7d66\u3055\u308c\u308bN\u306f\u5316\u5b66\u80a5\u6599\u7531\u6765\uff08\u5e74\u959363\u4e07\u30c8\u30f3\uff09\u304c\u6700\u3082\u591a\u304f\uff0c\u5bb6\u755c\u306e\u3075\u3093\u5c3f\u7531\u6765\u306eN(\u540c16\u4e07\u30c8\u30f3\uff09\u306f\uff0c\u751f\u7269\u7684N\u56fa\u5b9a\u3067\u571f\u306b\u306f\u3044\u308b\u91cf(\u540c22\u4e07\u30c8\u30f3\uff09\u3088\u308a\u5c11\u306a\u304b\u3063\u305f\u3002\u98fc\u990a\u3055\u308c\u3066\u3044\u308b\u5bb6\u755c\u306e\u982d\u6570\u304c\u5c11\u306a\u304b\u3063\u305f\u304b\u3089\u3067\u3042\u308b\u3002
\u3000\u6700\u7d42\u7684\u306b\uff11\u5e74\u9593\u3067\u5730\u4e0b\u6c34\u3084\u6cb3\u5ddd\u3078\u6d41\u51fa\u3057\u305fN\u306f\uff0c\u8fb2\u8015\u5730\u304b\u3089\u306e55\u4e07\u30c8\u30f3\u3068\uff0c\u4eba\u9593\u306e\u6392\u6cc4\u7269\uff08\u4e0b\u6c34\u51e6\u7406\u524d\u306e\u5024\uff09\u304b\u3089\u306e38\u4e07\u30c8\u30f3\u306e\u5408\u8a0893\u4e07\u30c8\u30f3\u3060\u3063\u305f\u3002\u3053\u306e\u307b\u304b\u5927\u6c17\u306b\u63ee\u6563\u3057\u305fN\uff08\u30a2\u30f3\u30e2\u30cb\u30a2\u30ac\u30b9\u3068\u3057\u3066\uff09\u306f\uff0c\u5316\u5b66\u80a5\u6599\u3084\u5bb6\u755c\u3075\u3093\u5c3f\u7531\u6765\u306e\u5408\u8a08\u30672\u4e07\u30c8\u30f3\u3060\u3063\u305f\u3002<\/p>\n\n\n\n
\uff12\uff092005\u5e74\u306eN\u5faa\u74b0\u91cf<\/h4>\n\n\n\n
\u3000In contrast, in 2005, the population was 128 million, 35% more than in 1961. The food self-sufficiency rate fell to 40%, resulting in a large increase in total imported N, 5.6 times that of 1961, to 890,000 tons (680,000 tons from crops, 140,000 tons from protein meal, and 70,000 tons from livestock products). Conversely, the amount of N entering agricultural land as biological N fixation, chemical fertilizers, and crop residues has decreased. This is because domestic food production has decreased.
\u3000Increased consumption of livestock products requires an increase in the number of livestock raised to support their production. The feed for the increased number of livestock is dependent on imports. Therefore, N contained in the imported feed is turned into livestock manure, which flows into agricultural lands. The amount of this inflow was 510,000 tons in 2005, 3.2 times the amount in 1961. Furthermore, the amount of N discharged from human excrement was also 1.8 times that of 1961. This is more than the population growth rate (35%), confirming the high protein content of food.
\u3000As a result, it was estimated that in 2005, the amount of N discharged from agricultural lands into groundwater and rivers increased to 840,000 tons per year, and the total of 670,000 tons discharged from human excrement into the environment was added, resulting in an annual discharge of 1.51 million tons into groundwater and rivers. This amount is 1.6 times that of 1961. The amount of N volatilized as ammonia gas from fertilizers and livestock manure into the atmosphere was 60,000 tons, three times the 1961 level.<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-45.png\")
<\/figure><\/div>\n\n\n\u3000\u308f\u304c\u56fd\u306e\u4f4e\u3044\u98df\u6599\u81ea\u7d66\u7387\u3068\u98df\u6599\u6d88\u8cbb\u52d5\u5411\u306e\u5909\u5316\u306f\uff0c\u6d77\u5916\u304b\u3089\u6301\u3061\u8fbc\u3080N\u91cf\u3092\u5927\u304d\u304f\u5897\u3084\u3057\u305f\u3002\u305d\u308c\u304c\u308f\u304c\u56fd\u306e\u5730\u4e0b\u6c34\uff0c\u6cb3\u5ddd\u306a\u3069\u306e\u6c34\u8cea\u6c5a\u6fc1\u3084\uff0c\u5927\u6c17\u74b0\u5883\u306e\u60aa\u5316\u3092\u62db\u304f\u53ef\u80fd\u6027\u306f\u5927\u304d\u3044\uff08Shindo\u3089,2009) \u3002\u307e\u3055\u306b\u4f4e\u81ea\u7d66\u7387\u3086\u3048\u306e\u554f\u984c\u3067\u3042\u308b\u3002
\u3000\u6b21\u56de\u306f\uff0c\u3053\u306e\u74b0\u5883\u306b\u6d41\u51fa\u3059\u308bN\u304c\u5177\u4f53\u7684\u306b\u3069\u306e\u3088\u3046\u306a\u74b0\u5883\u6c5a\u67d3\u6e90\u3068\u306a\u3063\u3066\u3044\u308b\u304b\u3092\u8003\u3048\u308b\u3002<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff15\u7ae0\u2212 \u8fb2\u696d\u306b\u8d77\u56e0\u3059\u308b\u74b0\u5883\u554f\u984c
\u7b2c27\u56de\u3000\u8fb2\u696d\u3068\u74b0\u5883\u554f\u984c\u2212\u305d\u306e\uff12
\u8fb2\u5730\u7531\u6765\u306e\u7a92\u7d20\u306b\u3088\u308b\u6c34\u8cea\u6c5a\u6fc1<\/h2>\n\n\n\n
\u4ee4\u548c\uff15 (2023) \u5e74\u300012\u6708\u53f7 (\u7b2c756\u53f7)<\/p>\n\n\n\n
\u3000\u524d\u56de\u8ff0\u3079\u305f\u3088\u3046\u306b\uff0c\u308f\u304c\u56fd\u306e\u98df\u6599\u81ea\u7d66\u7387\u306f\u4f4e\u3044\u305f\u3081\uff0c\u8f38\u5165\u3055\u308c\u308b\u98df\u6599\u3084\u5bb6\u755c\u98fc\u6599\u306a\u3069\u306b\u542b\u307e\u308c\u308b\u7a92\u7d20\uff08\uff2e\uff09\u306a\u3069\u306e\u4f5c\u7269\u990a\u5206\u304c\uff0c\u6d77\u5916\u304b\u3089\u591a\u91cf\u306b\u6301\u3061\u8fbc\u307e\u308c\u3066\u3044\u308b\u3002\u755c\u7523\u8fb2\u5bb6\u306b\u98fc\u6599\u3084\u80a5\u6599\u306e\u5f62\u3067\u591a\u91cf\u306e\u990a\u5206\u304c\u6301\u3061\u8fbc\u307e\u308c\u308b\u3068\uff0c\u305d\u306e\u8fb2\u5834\u3067\u306e\u571f\u2212\u98fc\u6599\u2212\u5bb6\u755c\u3092\u5de1\u308b\u990a\u5206\u5faa\u74b0\u304c\u7834\u7dbb\u3057\uff0c\u990a\u5206\u304c\u5468\u8fba\u74b0\u5883\u3078\u6d41\u51fa\u3059\u308b\u3002\u990a\u5206\u306e\u4e2d\u3067\u3082\uff0c\u3068\u304f\u306b\uff2e\u306f\u74b0\u5883\u3078\u306e\u60aa\u5f71\u97ff\u304c\u5927\u304d\u3044\u3002\u8015\u7a2e\u8fb2\u5bb6\u3067\u3082\uff0c\u5916\u90e8\u304b\u3089\u8fb2\u5730\u306b\u6301\u3061\u8fbc\u307e\u308c\u308b\uff2e\u304c\u571f\u306e\u4fdd\u6301\u5bb9\u91cf\u4ee5\u4e0a\u306b\u306a\u308b\u3068\uff0c\uff2e\u304c\u5468\u8fba\u74b0\u5883\u306b\u6d41\u51fa\u3059\u308b\u3002\u6d41\u51fa\u3057\u305f\uff2e\u304c\uff0c\u6cb3\u5ddd\u3084\u5730\u4e0b\u6c34\u3078\u5230\u9054\u3059\u308b\u3068\u6c34\u8cea\u6c5a\u6fc1\u3092\u62db\u304d\uff0c\u5927\u6c17\u306b\u5230\u9054\u3059\u308b\u3068\u5927\u6c17\u6c5a\u67d3\u3068\u306a\u3063\u3066\u74b0\u5883\u3092\u6c5a\u67d3\u3059\u308b\u3002
\u3000In this issue, we will consider water pollution among the environmental pollution caused by N discharged from agricultural land. Air pollution will be discussed in the next issue.<\/p>\n\n\n\n
1. eutrophication caused by water pollution<\/h3>\n\n\n\n
\u3000Sources of substances that adversely affect rivers, lakes, marshes, and other bodies of water through groundwater and surface runoff can be broadly classified into two categories: point sources (specific sources), which can be identified, and areal sources (non-specific sources), which cannot. Point sources (specific sources) and non-specific sources (non-specific sources). In addition to N, other substances such as phosphorus (P) and organic substances are discharged from these sources and cause water pollution.
\u3000\uff2e\u306f\u901a\u5e38\u30a2\u30f3\u30e2\u30cb\u30a2\u614bN\uff08NH4<\/sub>\u207a\u2212N\uff09\u306e\u5f62\u614b\u3067\u8fb2\u5730\u306b\u4e0e\u3048\u3089\u308c\u308b\u3002\u4e0e\u3048\u3089\u308c\u305fNH4<\/sub>\u207a\u2212N\u306f\uff0c\u571f\u306e\u5fae\u751f\u7269\u306b\u3088\u3063\u3066\u785d\u5316\u4f5c\u7528\u3092\u53d7\u3051\uff0c\u8ca0\u8377\u96fb\u30a4\u30aa\u30f3\u306e\u785d\u9178\u614b\uff2e\uff08NO3<\/sub>\u207b\u2212N\uff09\u306b\u5909\u5316\u3059\u308b\u3002\uff30\u3082\u901a\u5e38\u306f\uff0c\u8ca0\u8377\u96fb\u306e\u30ea\u30f3\u9178\u4e8c\u6c34\u7d20\u30a4\u30aa\u30f3\uff08H2<\/sub>PO4<\/sub>\u207b\uff09\u3068\u3057\u3066\u571f\u306b\u5b58\u5728\u3059\u308b\u3002\u3064\u307e\u308a\uff2e\u3084\uff30\u306e\u5f62\u614b\u306f\u3044\u305a\u308c\u3082\u8ca0\u8377\u96fb\u306e\u30a4\u30aa\u30f3\u3067\u3042\u308b\u305f\u3081\uff0c\u571f\u304c\u6301\u3064\u8ca0\u8377\u96fb\u3068\u53cd\u767a\u3057\u3042\u3063\u3066\u571f\u306b\u4fdd\u6301\u3055\u308c\u306b\u304f\u3044\u3002\u305d\u308c\u3086\u3048\uff0c\uff2e\u3084\uff30\u306f\u6cb3\u5ddd\u3084\u5730\u4e0b\u6c34\u306b\u6d41\u51fa\u3057\u3084\u3059\u304f\uff0c\u74b0\u5883\u6c5a\u67d3\u7269\u8cea\u306b\u306a\u308a\u3084\u3059\u3044\u3002
\u3000\u305d\u308c\u3089\u304c\u6e56\u6cbc\u3084\u6cb3\u5ddd\u306b\u6d41\u5165\u3059\u308b\u3053\u3068\u3067\uff0c\u305d\u306e\u6fc3\u5ea6\u304c\u9ad8\u307e\u308a\u990a\u5206\u304c\u5bcc\u5316\u3055\u308c\u3066\u3044\u304f\uff08\u3053\u308c\u3092\u5bcc\u6804\u990a\u5316\u3068\u3044\u3046) \u3002\u5bcc\u6804\u990a\u5316\u3059\u308b\u3068\u690d\u7269\u30d7\u30e9\u30f3\u30af\u30c8\u30f3\u3084\u6d6e\u904a\u6027\u30e9\u30f3\u85fb\u304c\u7570\u5e38\u767a\u751f\u3057\u3066\uff0c\u7dd1\u306e\u30da\u30f3\u30ad\u3092\u6d41\u3057\u305f\u3088\u3046\u306b\u6c34\u9762\u3092\u8986\u3044\u3064\u304f\u3057\u3066\u3057\u307e\u3046\u3053\u3068\u304c\u3042\u308b(\u56f3\uff11) \u3002\u3053\u308c\u304c\u6c34\u8cea\u6c5a\u6fc1\u306e\u7d42\u7740\u70b9\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-46.png\")
<\/figure><\/div>\n\n\n2. sources of environmental pollutants<\/h3>\n\n\n\n\uff11\uff09\u70b9\u6e90\u6c5a\u67d3<\/h4>\n\n\n\n
\u3000(1) Point source contamination
\u3000\u5178\u578b\u7684\u306a\u70b9\u6e90\u6c5a\u67d3\u3068\u3057\u3066\u306f\uff0c\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u4f8b\u304c\u3042\u308b\u3002\u3059\u306a\u308f\u3061\uff0c\u725b\u820e\uff0c\u8c5a\u820e\uff0c\u9d8f\u820e\u306a\u3069\u306e\u5468\u8fba\u3084\u5de5\u5834\uff0c\u4e0b\u6c34\u51e6\u7406\u5834\u306a\u3069\u306e\u8fd1\u304f\u3092\u901a\u904e\u3057\u305f\u6cb3\u5ddd\u306e\uff2e\u6fc3\u5ea6\u306e\u4e0a\u6607\uff0c\u3042\u308b\u3044\u306f\uff0c\u7d20\u6398\u308a\u3075\u3093\u5c3f\u3060\u3081\uff08\u30e9\u30b0\u30fc\u30f3\uff09\u306b\u8caf\u7559\u3057\u305f\u3075\u3093\u5c3f\u6df7\u5408\u7269\u7531\u6765\uff2e\u306b\u3088\u308b\u5730\u4e0b\u6c34\u306e\u6c5a\u6fc1\uff0c\u3055\u3089\u306b\uff0c\u653e\u7267\u5bb6\u755c\u304c\u6c34\u98f2\u307f\u5834\u3068\u3057\u3066\u5c0f\u6cb3\u5ddd\u3092\u5229\u7528\u3059\u308b\u6642\uff0c\u6cb3\u5ddd\u306b\u76f4\u63a5\u3075\u3093\u5c3f\u3092\u6392\u6cc4\u3059\u308b\u3053\u3068\u306a\u3069\u3067\u3042\u308b\u3002\u755c\u7523\u95a2\u9023\u65bd\u8a2d\u8fd1\u304f\u306e\u4e95\u6238\u6c34\u306eNO3\u2212\u2212N\u6fc3\u5ea6\u304c\u98f2\u7528\u57fa\u6e96\uff08\uff11\u30ea\u30c3\u30c8\u30eb\u5f53\u305f\u308a10mg\uff09\u3092\u4e0a\u56de\u308b\u3068\u3044\u3046\u5404\u5730\u306e\u4e8b\u4f8b\u306f\uff0c\u70b9\u6e90\u6c5a\u67d3\u306e\u5b9f\u4f8b\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
\uff12\uff09\u9762\u6e90\u6c5a\u67d3<\/h4>\n\n\n\n
\u3000\u8fb2\u5730\u306f\uff0c\u68ee\u6797\u3084\u5e02\u8857\u5730\u306a\u3069\u3068\u3068\u3082\u306b\u5e83\u304c\u308a\u306e\u3042\u308b\u571f\u5730\uff0c\u3059\u306a\u308f\u3061\u9762\u6e90\u3068\u3057\u3066\u6271\u308f\u308c\u308b\u3002\u9762\u6e90\u306b\u3088\u308b\u6c5a\u67d3\u304c\u9762\u6e90\u6c5a\u67d3\u3067\u3042\u308b\u3002\u3053\u306e\u6c5a\u67d3\u3067\u306f\u767a\u751f\u6e90\u304c\u7279\u5b9a\u3055\u308c\u306a\u3044\u305f\u3081\uff0c\u74b0\u5883\u6c5a\u67d3\u7269\u8cea\u304c\u3069\u3053\u304b\u3089\u767a\u751f\u3057\uff0c\u5730\u4e0b\u6c34\u3084\u6cb3\u5ddd\uff0c\u6e56\u6cbc\u3078\u3069\u306e\u7a0b\u5ea6\u6d41\u51fa\u3057\u3066\u3044\u308b\u304b\u3092\u5b9a\u91cf\u7684\u306b\u628a\u63e1\u3059\u308b\u306e\u304c\u96e3\u3057\u3044\u3002\u3057\u304b\u3057\uff0c\u5358\u4f4d\u96c6\u6c34\u57df\u9762\u7a4d\u5f53\u305f\u308a\u306e\u5bb6\u755c\u98fc\u990a\u982d\u6570\u304c\u591a\u304f\u306a\u308b\u3068\uff0c\u305d\u308c\u306b\u3068\u3082\u306a\u3063\u3066\uff2e\u6d41\u51fa\u91cf\u3082\u5897\u52a0\u3059\u308b\u305f\u3081\uff0c\u6cb3\u5ddd\u6c34\u306e\uff2e\u6fc3\u5ea6\u304c\u9ad8\u307e\u308b\uff08\u56f3\uff12) \u3002\u3064\u307e\u308a\u9762\u6e90\u6c5a\u67d3\u3067\u306f\uff0c\u74b0\u5883\u3078\u6c5a\u67d3\u7269\u8cea\u306e\u6d41\u51fa\u91cf\u304c\u5897\u52a0\u3059\u308c\u3070\u6c5a\u67d3\u306f\u78ba\u5b9f\u306b\u3059\u3059\u3080\u3002<\/p>\n\n\n
\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-47.png\")
<\/figure><\/div>\n\n\nWater Pollution Prevention Measures<\/h3>\n\n\n\n\uff11\uff09\u70b9\u6e90\u6c5a\u67d3\u5bfe\u7b56<\/h4>\n\n\n\n
\u3000Point source pollution in livestock farms often occurs when manure overflows from storage facilities and leaks into the environment because the size of the storage facility does not meet the appropriate capacity for the number of animals being kept. To prevent this, manure storage facilities have been regulated by the \"Law Concerning the Proper Management and Promotion of Utilization of Livestock Manure\" since 1999, and penalties have been imposed on facilities that violate the law.<\/p>\n\n\n\n
\uff12\uff09\u9762\u6e90\u6c5a\u67d3\u5bfe\u7b56\u2212\u2460\u8a31\u5bb9\u9650\u754cN\u91cf\u306e\u8a2d\u5b9a<\/h4>\n\n\n\n
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\uff13\uff09\u9762\u6e90\u6c5a\u67d3\u5bfe\u7b56\u2212\u2461\u5730\u5f62\u9023\u9396\u306e\u5229\u7528\u3084\u7de9\u885d\u5e2f\u306e\u8a2d\u7f6e<\/h4>\n\n\n\n
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\u3000\u6d44\u5316\u306e\u7a0b\u5ea6\u306f\u767a\u751f\u6e90\u3068\u6cb3\u5ddd\u306e\u9593\u9694\u304c\uff0c\u88f8\u5730\u72b6\u614b\u3088\u308a\u3082\u8349\u5730\u306e\u3088\u3046\u306b\u4f5c\u7269\u304c\u683d\u690d\u3055\u308c\u305f\u72b6\u614b\u306e\u307b\u3046\u304c\u5927\u304d\u3044\u3002\u3053\u306e\u76ee\u7684\u3067\u8a2d\u7f6e\u3055\u308c\u308b\u7de9\u885d\u5e2f\u306e\u5fc5\u8981\u5e45\u306f\uff0c\u70b9\u6e90\u6c5a\u67d3\u5bfe\u7b56\u3067\u6570\u301c\u6570\u5341m\uff0c\u9762\u6e90\u6c5a\u67d3\u3067\u6570\u5341m\u3068\u3055\u308c\u3066\u3044\u308b\u3002\u305f\u3060\u3057\uff0c\u3053\u306e\u7de9\u885d\u5e2f\u306e\u52b9\u679c\u306f\u571f\u5730\u6761\u4ef6\u3067\u5927\u304d\u304f\u5909\u5316\u3059\u308b\u305f\u3081\uff0c\u7de9\u885d\u5e2f\u306e\u5fc5\u8981\u5e45\u306b\u3064\u3044\u3066\u306e\u5177\u4f53\u7684\u306a\u57fa\u6e96\u306f\u793a\u3055\u308c\u3066\u3044\u306a\u3044\u3002<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff15\u7ae0\u2212 \u8fb2\u696d\u306b\u8d77\u56e0\u3059\u308b\u74b0\u5883\u554f\u984c
\u7b2c28\u56de\u3000\u8fb2\u696d\u3068\u74b0\u5883\u554f\u984c\u2212\u305d\u306e\uff13
\u8fb2\u5730\u7531\u6765\u306e\u7a92\u7d20\u306b\u3088\u308b\u5927\u6c17\u6c5a\u67d3\u2212\u30a2\u30f3\u30e2\u30cb\u30a2\u63ee\u6563<\/h2>\n\n\n\n
\u4ee4\u548c\uff16 (2024) \u5e74\u3000\uff11\u6708\u53f7 (\u7b2c757\u53f7)<\/p>\n\n\n\n
\u3000Livestock production in Japan has developed through dependence on imported concentrate feed. This has been the result of policy inducements since the end of World War II. This trend remains unchanged to this day, and the feed self-sufficiency rate is extremely low at 26%. Dependence on imported feed makes it possible to run a livestock business even if the farmland to produce feed for livestock is small. Thus, livestock production detached from the land increased the number of head of cattle raised, regardless of the area of land used for management. However, this means that instead of using the manure excreted daily by livestock as an important source of nutrients, it is likely to become a source of environmental pollution by dumping large amounts of manure on small farmlands.
\u3000\u4eca\u6708\u306f\uff0c\u5148\u6708\u306b\u7d9a\u304d\u8fb2\u5730\u304b\u3089\u74b0\u5883\u306b\u6d41\u51fa\u3059\u308b\u7a92\u7d20\uff08N) \uff0c\u3068\u304f\u306b\u5bb6\u755c\u3075\u3093\u5c3f\u7531\u6765N\u306e\u30a2\u30f3\u30e2\u30cb\u30a2\u63ee\u6563\u306b\u3088\u308b\u74b0\u5883\u554f\u984c\u3092\u8003\u3048\u308b\u3002<\/p>\n\n\n\n
1. negative environmental impact of volatilized ammonia<\/h3>\n\n\n\n
\u3000\u5bb6\u755c\u3075\u3093\u5c3f\u306b\u542b\u307e\u308c\u308b\u30a2\u30f3\u30e2\u30cb\u30a2\u614b\u7a92\u7d20\uff08NH4<\/sub>\u2212N\uff09\u306f\uff0c\u8349\u5730\u8868\u9762\u306b\u4e0e\u3048\u3089\u308c\u305f\u6642\u306e\u3088\u3046\u306b\uff0c\u5927\u6c17\u306b\u89e6\u308c\u308b\u3053\u3068\u3067\u30a2\u30f3\u30e2\u30cb\u30a2\u30ac\u30b9\uff08NH3<\/sub>\uff09\u306b\u306a\u3063\u3066\u5927\u6c17\u4e2d\u306b\u63ee\u6563\u3059\u308b\u3002
\u3000NH3<\/sub>\u63ee\u6563\u306f\uff0c\u4e0e\u3048\u305f\u80a5\u6599\u990a\u5206\u3068\u3057\u3066\u306eN\u306e\u640d\u5931\u3060\u3051\u3067\u306a\u304f\uff0c\u63ee\u6563\u3057\u305fNH3<\/sub>\u304c\u5927\u6c17\u4e2d\u306e\u786b\u9ec4\u9178\u5316\u7269\u3084\u7a92\u7d20\u9178\u5316\u7269\uff0c\u5869\u5316\u7269\u306a\u3069\u3068\u7d50\u5408\u3057\uff0c\u786b\u9178\u3084\u785d\u9178\uff0c\u5869\u9178\u3092\u542b\u3080\u96e8\u3068\u306a\u3063\u3066\u964d\u4e0b\u3059\u308b\u305f\u3081\uff0c\u3088\u308a\u5f37\u3044\u9178\u6027\u96e8\u306e\u767a\u751f\u6e90\u306b\u306a\u308b\u3002\u3053\u3046\u3057\u3066\u964d\u4e0b\u3057\u305fNH4<\/sub>\u2212N\u306f\uff0c\u6a39\u6728\u3084\u305d\u306e\u4ed6\u306e\u690d\u7269\u306e\u751f\u80b2\u3092\u304b\u304f\u4e71\u3057\uff0c\u571f\u306b\u6d78\u900f\u3057\u3066\u785d\u9178\u5316\u6210\u4f5c\u7528\u3092\u53d7\u3051\u308b\u3053\u3068\u3067\u571f\u306epH\u306e\u4f4e\u4e0b\u3068\uff0c\u305d\u308c\u306b\u4f34\u3046\u571f\u306e\u990a\u5206\u30d0\u30e9\u30f3\u30b9\u3092\u60aa\u5316\u3055\u305b\u308b\u306a\u3069\uff0c\u74b0\u5883\u306b\u5927\u304d\u306a\u60aa\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u3002
\u3000\u306a\u304a\uff0c\u5316\u5b66\u80a5\u6599\u3092\u571f\u306e\u8868\u9762\u306b\u4e0e\u3048\u3066\u3082\uff0c\u305d\u306e\u571f\u304c\u7279\u5225\u306a\u30a2\u30eb\u30ab\u30ea\u6027\u3067\u306a\u3044\u304b\u304e\u308a\uff0cNH3<\/sub>\u63ee\u6563\u306f\u5c11\u306a\u304f\uff0c\u5c3f\u7d20\u3067\u3054\u304f\u308f\u305a\u304b\u306b\u691c\u51fa\u3067\u304d\u308b\u7a0b\u5ea6\u3067\u3042\u308b\u3002\u307e\u305f\uff0c\u5bb6\u755c\u3075\u3093\u5c3f\u304c2cm\u7a0b\u5ea6\u306e\u308f\u305a\u304b\u306a\u539a\u307f\u3067\u3082\u571f\u306b\u8986\u308f\u308c\u308b\u3068\uff0cNH3<\/sub>\u63ee\u6563\u306f\u307b\u3068\u3093\u3069\u767a\u751f\u3057\u306a\u3044(Matsunaka\u3089\uff0c2008) \u3002<\/p>\n\n\n\n\uff12\uff0e\u8349\u5730\u8868\u9762\u306b\u4e0e\u3048\u3089\u308c\u305f\u5bb6\u755c\u3075\u3093\u5c3f\u304b\u3089\u306eNH3<\/sub>\u63ee\u6563\u3068\u305d\u308c\u306b\u95a2\u308f\u308b\u8981\u56e0<\/h3>\n\n\n\n\u3000\u8349\u5730\u8868\u9762\u306b\u4e0e\u3048\u3089\u308c\u305f\u5bb6\u755c\u3075\u3093\u5c3f\u304b\u3089\u306e\u5358\u4f4d\u6642\u9593\u5f53\u305f\u308aNNH3<\/sub>\u2212N\u63ee\u6563\u91cf\uff08NH3<\/sub>\u2212N\u63ee\u6563\u901f\u5ea6\uff09\u306e\u30d4\u30fc\u30af\u306f\uff0c\u304a\u304a\u3080\u306d\u4e0e\u3048\u3089\u308c\u3066\u304b\u3089\u6570\u6642\u9593\u4ee5\u5185\u306b\u73fe\u308c\uff0cNH3<\/sub>\u63ee\u6563\u306f\u6570\u65e5\u4ee5\u5185\u3067\u7d42\u4e86\u3059\u308b\uff08\u56f3\uff11) \u3002
\u3000\u4e0e\u3048\u3089\u308c\u305fNH4<\/sub>\u2212N\u91cf\u306b\u5bfe\u3059\u308b\u63ee\u6563\u3057\u305fNH3<\/sub>\u2212N\u91cf\u306e\u5272\u5408\u3092\u30a2\u30f3\u30e2\u30cb\u30a2\u63ee\u6563\u7387\uff08\u4ee5\u4e0b\uff0cNH3<\/sub>\u63ee\u6563\u7387\u3068\u8a18\u3059\uff09\u3068\u3044\u3046\u3002\u4e73\u725b\u30b9\u30e9\u30ea\u30fc\uff08\u4e73\u725b\u304c\u6392\u6cc4\u3057\u305f\u3075\u3093\u3068\u5c3f\uff0c\u305d\u308c\u306b\u30aa\u30ac\u30af\u30ba\u306e\u3088\u3046\u306a\u6577\u6599\u304c\u52a0\u308f\u3063\u305f\u6df7\u5408\u7269\uff09\u3092\u8349\u5730\u8868\u9762\u306b\u4e0e\u3048\u305f\u5834\u5408\uff0c\u30a2\u30f3\u30e2\u30cb\u30a2\u63ee\u6563\u7387\u306f\u30b9\u30e9\u30ea\u30fc\u306e\u4e0e\u3048\u305f\u91cf\u304c60t\/ha\u307e\u3067\u306a\u308930\uff05\u7a0b\u5ea6\u3067\u3042\u308b\uff08Matsunaka\u3089\uff0c2008) \u3002
\u3000\u3053\u306eNH3<\/sub>\u63ee\u6563\u7387\u306f\uff0c\u30b9\u30e9\u30ea\u30fc\u306epH\u3084\u4e7e\u7269\u7387\u304c\u9ad8\u304f\uff0c\u307e\u305f\uff0c\u4e0e\u3048\u305f\u6642\u306e\u6c17\u6e29\u304c\u9ad8\u3044\u307b\u3069\u9ad8\u307e\u308b\u3002\u3057\u304b\u3057\u571f\u304c\u4e7e\u71e5\u3057\u3066\u3044\u308b\u3068\uff0c\u30b9\u30e9\u30ea\u30fc\u306eNH4<\/sub>\u2212N\u304c\u571f\u306e\u4e2d\u306b\u6d78\u5165\u3057\u3084\u3059\u304f\u306a\u308b\u305f\u3081\u63ee\u6563\u7387\u306f\u4f4e\u4e0b\u3059\u308b\u3002\u3053\u308c\u3089\u306e\u8981\u56e0\u306e\u3046\u3061\uff0c\u6c17\u6e29\u304cNH3<\/sub>\u63ee\u6563\u306b\u6700\u3082\u5927\u304d\u306a\u5f71\u97ff\u3092\u4e0e\u3048\u308b\uff08Matsunaka\u3089\uff0c2002) \u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-48.png\")
<\/figure><\/div>\n\n\n\uff13\uff0e\u8349\u5730\u8868\u9762\u306b\u4e0e\u3048\u3089\u308c\u305f\u5bb6\u755c\u3075\u3093\u5c3f\u304b\u3089\u306eNH3<\/sub>\u63ee\u6563\u3092\u6291\u5236\u3059\u308b\u5bfe\u7b56<\/h3>\n\n\n\n\u3000\u8349\u5730\u3084\u571f\u306e\u8868\u9762\u306b\u4e0e\u3048\u3089\u308c\u305f\u5bb6\u755c\u3075\u3093\u5c3f\u304b\u3089\u306eNH3<\/sub>\u63ee\u6563\u3092\u5b8c\u5168\u306b\u9632\u3050\u3053\u3068\u306f\uff0c\u4e0e\u3048\u305f\u5f8c\u306b\u591a\u91cf\u306e\u964d\u96e8\u304c\u306a\u3044\u304b\u304e\u308a\u4e8b\u5b9f\u4e0a\u4e0d\u53ef\u80fd\u3067\u3042\u308b\u3002\u3057\u304b\u3057\uff0c\u3075\u3093\u5c3f\u306e\u4e0e\u3048\u65b9\u3092\u5de5\u592b\u3057\uff0c\u4e0e\u3048\u305f\u3075\u3093\u5c3f\u3092\u5927\u6c17\u306b\u89e6\u308c\u306b\u304f\u304f\u3059\u308c\u3070\uff0c\u63ee\u6563\u7387\u306e\u4f4e\u4e0b\u306b\u3064\u306a\u304c\u308b\u3002
\u3000\u4f8b\u3048\u3070\uff0c\u4e73\u725b\u30b9\u30e9\u30ea\u30fc\u3092\u8349\u5730\u306e\u8868\u9762\u306b\u4e0e\u3048\u308b\u6642\u306b\u5229\u7528\u3059\u308b\u65b9\u6cd5\u3068\u3057\u3066\uff0c\u885d\u7a81\u677f\u65b9\u5f0f\uff08\u30b9\u30d7\u30e9\u30c3\u30b7\u30e5\u30d7\u30ec\u30fc\u30c8\uff0c\u56f3\uff12\u2212a) \uff0c\u5e2f\u72b6\u65bd\u4e0e\u6cd5\uff08\u30d0\u30f3\u30c9\u30b9\u30d7\u30ec\u30c3\u30c9\uff0c\u56f3\uff12\u2212b) \uff0c\u6d45\u5c64\u6ce8\u5165\u6cd5\uff08\u30b7\u30e3\u30ed\u30a6\u30a4\u30f3\u30b8\u30a7\u30af\u30b7\u30e7\u30f3\uff0c\u56f3\uff12\u2212c\uff09\u306a\u3069\u304c\u3042\u308b\u3002\u3053\u306e\u3046\u3061\uff0c\u308f\u304c\u56fd\u3067\u4e00\u822c\u7684\u306b\u5229\u7528\u3055\u308c\u3066\u3044\u308b\u306e\u304c\u885d\u7a81\u677f\u65b9\u5f0f\u3067\u3042\u308b\u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-49.jpg\")
<\/figure><\/div>\n\n\n\u3000\u3053\u306e\u65b9\u5f0f\u306f\u4ed6\u306e\u4e0e\u3048\u65b9\u306b\u6bd4\u3079\u3066\uff0c\u30b9\u30e9\u30ea\u30fc\u304c\u7a7a\u6c17\u306b\u89e6\u308c\u3084\u3059\u3044\u305f\u3081\uff0cNH3<\/sub>\u63ee\u6563\u7387\u304c\u6700\u3082\u9ad8\u3044\uff08\u56f3\uff13) \u3002\u3053\u306e\u4e0e\u3048\u65b9\u306b\u6bd4\u8f03\u3059\u308b\u3068\uff0c\u6d45\u5c64\u6ce8\u5165\u6cd5\u306a\u3089\u63ee\u6563\u640d\u5931\u309277\uff05\u524a\u6e1b\u3067\u304d\uff0c\u5e2f\u72b6\u65bd\u4e0e\u6cd5\u306f\u63ee\u6563\u640d\u5931\u309236\uff05\u524a\u6e1b\u3059\u308b\u3060\u3051\u3067\u306a\u304f\uff0c\u3075\u3093\u5c3f\u6563\u5e03\u5f8c\u306e\u60aa\u81ed\u5f37\u5ea6\u3092\u4f4e\u4e0b\u3055\u305b\u308b\u52b9\u679c\u3082\u5927\u304d\u3044\uff08\u56f3\uff14) \u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-49.png\")
<\/figure><\/div>\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-50.png\")
<\/figure><\/div>\n\n\n\u3000\u8fb2\u696d\u306b\u3088\u308b\u74b0\u5883\u6c5a\u67d3\u306e\u6291\u5236\u306b\u7a4d\u6975\u7684\u306b\u53d6\u308a\u7d44\u3080EU\uff08\u30e8\u30fc\u30ed\u30c3\u30d1\u9023\u5408\uff09\u3067\u306f\uff0c\u5148\u6708\u8ff0\u3079\u305f\u3088\u3046\u306b\uff0c\u3075\u3093\u5c3f\u7531\u6765N\u306e\u8fb2\u5730\u3078\u306e\u6295\u5165\u91cf\u3092\u6700\u5927170kg\/ha\u306b\u6cd5\u7684\u898f\u5236\u3057\u3066\u3044\u308b\u3002\u305d\u308c\u3060\u3051\u3067\u306a\u304f\uff0c\u74b0\u5883\u3078\u306e\u60aa\u5f71\u97ff\u304c\u5927\u304d\u3044NH3<\/sub>\u63ee\u6563\u3092\u6291\u5236\u3059\u308b\u305f\u3081\u306b\uff0c\u63ee\u6563\u7387\u304c\u9ad8\u304f\uff0c\u60aa\u81ed\u5f37\u5ea6\u304c\u5f37\u3044\u885d\u7a81\u677f\u65b9\u5f0f\u306b\u3088\u308b\u4e73\u725b\u30b9\u30e9\u30ea\u30fc\u6563\u5e03\u3092\u7981\u6b62\u3057\u3066\u3044\u308b\u3002\u308f\u304c\u56fd\u3067\u306f\u3053\u306e\u3088\u3046\u306a\u5f37\u3044\u898f\u5236\u304c\u306a\u3044\u307e\u307e\uff0c\u5bb6\u755c\u3075\u3093\u5c3f\u306b\u3088\u308b\u74b0\u5883\u6c5a\u67d3\u554f\u984c\u304c\u7d99\u7d9a\u3057\u3066\u3044\u308b\u3002<\/p>\n\n\n\n\u3000<\/p>\n\n\n\n
\u3000<\/p>\n\n\n\n
\u2212\u7b2c\uff15\u7ae0\u2212 \u8fb2\u696d\u306b\u8d77\u56e0\u3059\u308b\u74b0\u5883\u554f\u984c
\u7b2c29\u56de\u3000\u8fb2\u696d\u3068\u74b0\u5883\u554f\u984c\u2212\u305d\u306e\uff14
\u8fb2\u5730\u7531\u6765\u306e\u7a92\u7d20\u306b\u3088\u308b\u5927\u6c17\u6c5a\u67d3\u2212\u4e00\u9178\u5316\u4e8c\u7a92\u7d20\u6392\u51fa<\/h2>\n\n\n\n
\u4ee4\u548c\uff16 (2024) \u5e74 2\/3\u6708\u5408\u4f75\u53f7 (\u7b2c758\u53f7)<\/p>\n\n\n\n
\u3000\u4eca\u56de\u3082\uff0c\u524d\u56de\u306e\u30a2\u30f3\u30e2\u30cb\u30a2\u63ee\u6563\u306b\u7d9a\u304d\uff0c\u8fb2\u5730\u306b\u7531\u6765\u3059\u308b\u7a92\u7d20\uff08N\uff09\u306b\u3088\u308b\u5927\u6c17\u6c5a\u67d3\u306e\u8a71\u984c\u3067\uff0c\u6e29\u5ba4\u52b9\u679c\u30ac\u30b9\u306e\u4e3b\u8981\u306a\u3082\u306e\u306e\u4e00\u3064\uff0c\u4e00\u9178\u5316\u4e8c\u7a92\u7d20(N2O\uff0c\u4e9c\u9178\u5316\u7a92\u7d20\u3068\u3082\u3044\u3046\uff09\u3092\u53d6\u308a\u4e0a\u3052\u308b\u3002
\u3000\u306a\u304a\uff0cN2O\u4ee5\u5916\u306e\u6e29\u5ba4\u52b9\u679c\u30ac\u30b9\u306b\u3064\u3044\u3066\u3084\uff0c\u5730\u7403\u898f\u6a21\u304b\u3089\u307f\u305f\u6e29\u5ba4\u52b9\u679c\u30ac\u30b9\u3068\u8fb2\u696d\u3068\u306e\u95a2\u308f\u308a\u306f\uff0c\u6b21\u56de\uff0c\u7dcf\u5408\u7684\u306b\u8003\u3048\u308b\u3053\u3068\u306b\u3059\u308b\u3002<\/p>\n\n\n\n
1. N2O generation (direct emission) and soil moisture conditions<\/h3>\n\n\n\n
\u3000N2O\u306e\u6e29\u5ba4\u52b9\u679c\u306f\uff0c\u4e8c\u9178\u5316\u70ad\u7d20\uff08CO2<\/sub>\uff09\u306e298\u500d\u3082\u5f37\u529b\u3067\u3042\u308b\u3002\u307e\u305f\uff0c\u6210\u5c64\u570f\u30aa\u30be\u30f3\u5c64\u306e\u7834\u58ca\u306b\u3082\u95a2\u4e0e\u3057\u3066\u304a\u308a\uff0c\u74b0\u5883\u3078\u306e\u60aa\u5f71\u97ff\u304c\u5927\u304d\u3044\u3002
\u3000\u8fb2\u5730\u3067N2O\u304c\u767a\u751f\u3059\u308b\u306e\u306f\uff0c\u5fae\u751f\u7269\u306e\u50cd\u304d\u304c\u95a2\u308f\u308b\u4e8c\u3064\u306e\u7d4c\u8def\u304c\u3042\u308b\u3002\u4e00\u3064\u306f\uff0c\u5bb6\u755c\u6392\u6cc4\u7269\u306a\u3069\u304b\u3089\u751f\u7523\u3055\u308c\u308b\u6709\u6a5f\u8cea\u80a5\u6599\u3084\u5316\u5b66\u80a5\u6599\u306e\u5f62\u614b\u3067\uff0c\u8fb2\u5730\u306b\u4e0e\u3048\u3089\u308c\u305f\u30a2\u30f3\u30e2\u30cb\u30a2\u614b\u7a92\u7d20\uff08NH4<\/sub>\u2212N)\u304c\u9178\u7d20\u306e\u3042\u308b\u6761\u4ef6\uff08\u9178\u5316\u7684\u6761\u4ef6\uff09\u3067\uff0c\u785d\u9178\u614b\u7a92\u7d20(NO3\u2212N\uff09\u306b\u5909\u5316\u3059\u308b\u6642\uff08\u3053\u306e\u5909\u5316\u3092\u785d\u9178\u5316\u6210\u3068\u3044\u3046\uff09\u306e\u526f\u751f\u6210\u7269\u3068\u3057\u3066\u767a\u751f\u3059\u308b\u7d4c\u8def\u3067\u3042\u308b\u3002\u3082\u3046\u4e00\u3064\u306f\uff0c\u785d\u9178\u5316\u6210\u3067\u3067\u304d\u305fNO3\u2212N\u304c\uff0c\u9178\u7d20\u4e0d\u8db3\u306e\u6761\u4ef6\uff08\u9084\u5143\u7684\u6761\u4ef6\uff09\u306b\u7f6e\u304b\u308c\u3066\uff0c\u7a92\u7d20\u30ac\u30b9(N2\uff09\u3078\u5f62\u614b\u5909\u5316\u3059\u308b\uff08\u3053\u306e\u5909\u5316\u3092\u8131\u7a92\u3068\u3044\u3046)\u6642\u306e\u4e2d\u9593\u7523\u7269\u3068\u3057\u3066\u767a\u751f\u3059\u308b\u7d4c\u8def\u3067\u3042\u308b\u3002
\u3000\u571f\u306e\u4e2d\u304c\u9178\u5316\u7684\u6761\u4ef6\u3067\u3042\u308b\u304b\uff0c\u9084\u5143\u7684\u6761\u4ef6\u3067\u3042\u308b\u304b\u306f\uff0c\u571f\u306e\u4e2d\u306e\u3059\u3079\u3066\u306e\u9699\u9593\uff08\u5168\u5b54\u9699\uff09\u304c\u6c34\u5206\u3067\u3069\u306e\u7a0b\u5ea6\u57cb\u3081\u5c3d\u304f\u3055\u308c\u3066\u3044\u308b\u304b\uff08\u3053\u308c\u3092\u6c34\u5206\u98fd\u548c\u5ea6\uff08\u7565\u79f0WFPS\uff1dWater Filled Pore Space\uff09\u3068\u3044\u3046\uff09\u3067\u6c7a\u307e\u308b\u3002\u571f\u306e\u6c34\u5206\u98fd\u548c\u5ea6\u304c60\uff05\uff08\u785d\u9178\u5316\u6210\u306e\u5fae\u751f\u7269\u6d3b\u52d5\u306b\u306f\u307b\u3069\u3088\u3044\u6c34\u5206\u72b6\u614b\uff09\u304b\u308970\uff05(\u571f\u304c\u3084\u3084\u6e7f\u3063\u305f\u72b6\u614b\uff09\u306e\u7bc4\u56f2\u3067\uff0c\u785d\u9178\u5316\u6210\u3084\u8131\u7a92\u306e\u4e8c\u3064\u306e\u4f5c\u7528\u304c\u9032\u884c\u3059\u308b\u305f\u3081\uff0cN2O\u306e\u767a\u751f\u304c\u591a\u304f\u306a\u3063\u3066\u571f\u304b\u3089\u5927\u6c17\u306b\u6392\u51fa\u3055\u308c\u308b\uff08\u56f3\uff11) \u3002\u6c34\u5206\u98fd\u548c\u5ea6\u304c80\uff05\u3092\u4e0a\u56de\u308b\u6e7f\u6f64\u306a\u72b6\u614b\u3067\u306f\uff0c\u9084\u5143\u7684\u6761\u4ef6\u304c\u5f37\u307e\u308a\u8131\u7a92\u306b\u3088\u3063\u3066\uff0c\u4e3b\u306bN2\u304c\u751f\u6210\u3057\u3066\u6392\u51fa\u3055\u308c\uff0cN2O\u306e\u6392\u51fa\u306f\u5c11\u306a\u3044\u3002\u9006\u306b\uff0c\u6c34\u5206\u98fd\u548c\u5ea6\u304c50\uff05\u3088\u308a\u4f4e\u3044\u5834\u5408\u306f\uff0c\u4e7e\u71e5\u72b6\u614b\u3068\u306a\u308a\u785d\u9178\u5316\u6210\u304c\u4e2d\u5fc3\u3067\uff0c\u4e3b\u306b\u4e00\u9178\u5316\u7a92\u7d20\uff08NO\uff09\u304c\u6392\u51fa\u3055\u308c\u308b\u3002
\u3000N2O\u6392\u51fa\u306b\u597d\u9069\u306a\u6c34\u5206\u98fd\u548c\u5ea660\u301c70\uff05\u3068\u306f\uff0c\u6c34\u5206\u72b6\u614b\u304c\u4f5c\u7269\u751f\u7523\u306b\u6bd4\u8f03\u7684\u826f\u597d\u306a\u72b6\u614b\u3068\u91cd\u306a\u308b\u3002\u3057\u305f\u304c\u3063\u3066\uff0c\u8fb2\u5730\u3078\u306eN\u65bd\u4e0e\u91cf\u304c\u9069\u6b63\u91cf\u3067\u3042\u3063\u305f\u3068\u3057\u3066\u3082\uff0cN2O\u306e\u767a\u751f\u3092\u5b8c\u5168\u306b\u6291\u6b62\u3059\u308b\u306e\u306f\u96e3\u3057\u3044\u3002\u307e\u305f\uff0c\u5730\u6e29\u304c\u9ad8\u307e\u308b\u3068\u5fae\u751f\u7269\u6d3b\u6027\u304c\u9ad8\u307e\u3063\u3066N2O\u306e\u767a\u751f\u91cf\u3082\u591a\u304f\u306a\u308b\u3002
\u3000\u3053\u306e\u3088\u3046\u306b\u571f\u306e\u4e2d\u3067\u767a\u751f\u3057\u305fN2O\u304c\u305d\u306e\u307e\u307e\u5927\u6c17\u306b\u6392\u51fa\u3055\u308c\u308b\u3053\u3068\u3092\u76f4\u63a5\u6392\u51fa\u3068\u3044\u3046\u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-51.png\")
<\/figure><\/div>\n\n\n\uff12\uff0e\u6c34\u306b\u6eb6\u3051\u305fN2O\u304b\u3089\u306e\u6392\u51fa\u2212\u9593\u63a5\u6392\u51fa<\/h3>\n\n\n\n
\u3000\u8fb2\u5730\u3067\u767a\u751f\u3057\u305fN2O\u306e\u4e00\u90e8\u306f\uff0c\u571f\u306e\u4e2d\u306e\u6c34\u5206(\u571f\u58cc\u6eb6\u6db2\uff09\u3084\u5730\u4e0b\u6c34\u306b\u6eb6\u3051\u8fbc\u307f\uff0c\u904e\u98fd\u548c\u306e\u72b6\u614b\u3067\u6eb6\u5b58\u3057\u3066\u3044\u308b\u3002\u3053\u306e\u904e\u98fd\u548c\u3067N2O\u3092\u542b\u3080\u6eb6\u6db2\u304c\uff0c\u6697\u6e20\u6392\u6c34\u3084\u6e67\u6c34\uff0c\u6cb3\u5ddd\u6c34\u3068\u3057\u3066\u5927\u6c17\u306b\u958b\u653e\u3055\u308c\u308b\u3068\uff0cN2O\u306f\u904e\u98fd\u548c\u72b6\u614b\u304c\u89e3\u9664\u3055\u308c\u308b\u305f\u3081\uff0c\u5927\u6c17\u306b\u6392\u51fa\u3055\u308c\u3066\u3044\u304f\u3002\u3055\u3089\u306b\uff0c\u524d\u56de\u304a\u8a71\u3057\u3057\u305f\u30a2\u30f3\u30e2\u30cb\u30a2\u63ee\u6563\u306b\u3088\u3063\u3066\u5927\u6c17\u3078\u51fa\u3066\u3044\u3063\u305fNH4<\/sub>\u2212N\u304c\uff0c\u964d\u96e8\u306b\u6eb6\u3051\u8fbc\u3093\u3067\u571f\u306b\u623b\u3063\u3066\u304f\u308b\u3068\uff0c\u571f\u306e\u4e2d\u3067\u785d\u9178\u5316\u6210\u3092\u53d7\u3051\uff0c\u305d\u306e\u526f\u751f\u6210\u7269\u3067N2O\u304c\u767a\u751f\u3059\u308b\u3002
\u3000Such emissions are known as indirect emissions and, like direct emissions, are not negligible.<\/p>\n\n\n\n3. N2O emissions in Japan and their relation to agriculture<\/h3>\n\n\n\n
\u30002021\u5e74\u306e\u308f\u304c\u56fd\u3067\u6392\u51fa\u3055\u308c\u305fN2O\u306e\u7dcf\u91cf\u306f\uff0cCO2<\/sub>\u306b\u63db\u7b97\u3057\u306619.9Mt\uff08\u30e1\u30ac\u30c8\u30f3\uff1d\u767e\u4e07\u30c8\u30f3\uff09\u3060\u3063\u305f (\u65e5\u672c\u56fd\u6e29\u5ba4\u52b9\u679c\u30ac\u30b9\u30a4\u30f3\u30d9\u30f3\u30c8\u30ea\u5831\u544a\u66f8\uff0c2023\u5e74) \u3002\u3053\u308c\u306f\uff0c1990\u5e74\u306b\u6bd4\u8f03\u305740\uff05\u3082\u524a\u6e1b\u3055\u308c\u3066\u3044\u308b\uff08\u56f3\uff12) \u3002\u3053\u306e\u3046\u3061\uff0c\u8fb2\u696d\u5206\u91ce\u304b\u3089\u6392\u51fa\u3055\u308c\u305fN2O\u91cf\u306fCO2<\/sub>\u63db\u7b97\u30679.6Mt\uff0c\u7dcf\u6392\u51fa\u91cf\u306e48\uff05\u3092\u5360\u3081\u308b\u5927\u304d\u306a\u6392\u51fa\u6e90\u3067\u3042\u308b\u3002\u3057\u304b\u3082\u5de5\u696d\u30d7\u30ed\u30bb\u30b9\u53ca\u3073\u88fd\u54c1\u306e\u4f7f\u7528\u306e\u5206\u91ce\u3067\u306f\uff0c1990\u5e74\u304b\u30892021\u5e74\u306b\u6392\u51fa\u6291\u5236\u304c\u5927\u304d\u304f\u6210\u529f\u3057\u305f\u306e\u306b\u5bfe\u3057\u3066\uff0c\u8fb2\u696d\u5206\u91ce\u306e\u6291\u5236\u306f\u308f\u305a\u304b\u306b\u3059\u304e\u306a\u3044\uff08\u56f3\uff12) \u3002<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.jcam-agri.co.jp\/wordpress\/wp-content\/uploads\/2025\/09\/image-52.png\")
<\/figure><\/div>\n\n\n\u3000\u8fb2\u696d\u306b\u7531\u6765\u3059\u308bN2O\u306f\uff0c\u4e3b\u306b\u5bb6\u755c\u6392\u6cc4\u7269\u306e\u7ba1\u7406\u304b\u3089\u3068\u8fb2\u5730\u306e\u571f\u304b\u3089\u6392\u51fa\u3055\u308c\u308b\u3002\u3059\u306a\u308f\u3061\uff0c\u5bb6\u755c\u6392\u6cc4\u7269\u3092\u7ba1\u7406\u3057\u3066\u3044\u308b\u6642\u306b\uff0c\u6392\u6cc4\u7269\u4e2d\u3067\u785d\u9178\u5316\u6210\u3084\u8131\u7a92\u304c\u767a\u751f\u3057\uff0cN2O\u304c\u76f4\u63a5\u6392\u51fa\u3055\u308c\u308b\u5834\u5408\u3068\uff0c\u7ba1\u7406\u904e\u7a0b\u3067\u306e\u30a2\u30f3\u30e2\u30cb\u30a2\u63ee\u6563\u3092\u8d77\u70b9\u3068\u3059\u308b\u9593\u63a5\u6392\u51fa\u3067\u3042\u308b\u3002\u8fb2\u5730\u306e\u571f\u306b\u7531\u6765\u3059\u308b\u306e\u306f\uff0c\u5316\u5b66\u80a5\u6599\u3084\u6709\u6a5f\u8cea\u80a5\u6599\u304c\u8fb2\u5730\u306b\u4e0e\u3048\u3089\u308c\u305f\u6642\uff0c\u3053\u308c\u3089\u8cc7\u6750\u306b\u542b\u307e\u308c\u308bN\u304c\uff0c\u8fb2\u5730\u306e\u571f\u306e\u4e2d\u3067\u785d\u9178\u5316\u6210\u3084\u8131\u7a92\u306e\u4f5c\u7528\u3092\u53d7\u3051\uff0cN2O\u304c\u76f4\u63a5\u6392\u51fa\u3055\u308c\u308b\u5834\u5408\u3068\uff0c\u751f\u6210\u3057\u305fNO3\u2212N\u304c\u5730\u4e0b\u6c34\u306a\u3069\u306b\u6eb6\u5b58\u3057\u305f\u5f8c\uff0c\u9593\u63a5\u6392\u51fa\u3055\u308c\u308b\u5834\u5408\u3067\u3042\u308b\u3002\u3055\u3089\u306b\uff0c\u8fb2\u4f5c\u7269\u6b8b\u6e23\u306e\u71c3\u713c(\u91ce\u713c\u304d\uff09\u3067\u3082\u6392\u51fa\u3055\u308c\u308b\u3002\u3057\u304b\u3057\uff0c\u305d\u306e\u91cf\u306f\u6975\u3081\u3066\u308f\u305a\u304b\u3067\u3042\u308b\uff08\u56f3\uff13) \u3002