Agriculture and Science 2022/2/3

Experiencing high-yield technology using a combination of side-row fertilizer application and seedling box placement

Jcam Agri Corporation Tohoku Branch
　Masao Ueno Technical Advisor

Introduction.

　The "leave it in the seedling box" method has been in the limelight as an ultimate labor-saving and low-cost fertilizer application technology that can produce good quality seedlings without any fertilizer failure by suppressing the initial leaching of nitrogen in the seedling box as much as possible, and then transplanting them into the field for field fertilization. On the other hand, the initial leaching of fertilizer from the rice field by leaving the seedlings in the seedling box is inevitably slow, and nitrogen emission due to the dry-soil effect is not always observed.
On fertile soils with high soil fertility, the initial growth of the seedlings is adequate, but on low fertility soils, the initial growth of the seedlings is inevitably insufficient. If we consider the one-shot application of total basal fertilizer as a counterpart to the box-applied fertilizer, we believe that the total basal fertilizer technique is superior in the early stage of growth, and the box-applied fertilizer technique is superior in the late stage of growth.

　Therefore, when considering high-yield technology based on seedling box-assisted fertilization, it is natural to assume that combining side-row fertilization, which ensures early growth, with seedling box-assisted fertilization, which is good at late leaching, is a reasonable high-yield technology. Here, we introduce the basic concept of high-yield technology and a local high-yield technology that combines side-row fertilizer application and seedling box-applied fertilizer.

Seedling technology using seedling boxes
(High nitrogen quality seedlings are produced by pooled seedling cultivation and box-bottom fertilization, which is left up to the seedling box).

　There are three ways to use box-makase: mixed application of bedding soil and box-makase, layered application, and box-bottom application. The author recommends box-bottom fertilization. Consider the area around the seed rice when seedling seed roots begin to grow. As shown in Figure 1, in the case of layered fertilization, the seeds and the seedling box are living together. In contrast, in box-bottom fertilization, the seed is sandwiched between the bedding soil and the covering soil because the seedling box is at the bottom of the box. This results in a difference in moisture retention. After the seedlings are ready to sprout, lack of moisture can be fatal to the seedlings. It is important to use a bedding medium with high water retention capacity and to apply fertilizer at the bottom of the seedling box. This does not negate the need for layered fertilization. The solution is to pay close attention to irrigation.

　Pool irrigation (Photo 1) is recommended. The most important thing for box-grown seedlings is to achieve uniform germination length. The most important thing for box-raised seedlings is to keep the emergence length as short as possible. The budding length should be kept strictly within 0.5 to 1 cm. Long sprouting length is "a hundred harms and not a hundred good". Once the seedlings have sprouted, use pooled seedlings and imagine the conditions of a water nursery. It is acceptable to stop watering after one day, depending on the condition of the pool-grown seedlings, and irrigate again after 2 to 3 days, and it is good if the seedlings stay under water after 1 to 1.5 leaves. If the water temperature rises abnormally after Golden Week, it is necessary to change the water. Water should be removed 2 to 3 days prior to rice planting. As we have pointed out many times in the past, seedlings grown in a seedling box are prone to water shortage because the amount of soil is reduced by the amount of fertilizer applied to the seedlings. Pool irrigation is the best way to solve this problem. Again, it is important to keep the seedlings in a "waterlogged nursery" to prevent water shortage after seedling emergence. This is why we recommend pooled irrigation.

　Another important thing is to control seedling elongation after the budding stage in the case of greenhouse seedling production. This means controlling the length of emergence, the height of the first leaf sheath, and the height of the second leaf sheath. To achieve this, the temperature inside the greenhouse should not be increased. Open the greenhouse first thing in the morning except in the event of low temperatures, rainfall, or strong winds. Furthermore, if the temperature rises, we aim to open the greenhouse to its full extent. The key is to keep the temperature inside the greenhouse at a moderate level, and to keep the greenhouse at 1.5 leaves, which is too short for the seedlings to grow. In the latter half of seedling growth, about 2% of the nitrogen in the seedling box is leached out. This ensures good quality seedlings with high nitrogen content, or "Zunguri" seedlings.

2. dry-soil effect on early growth of paddy rice

　The amount of nitrogen in paddy soils is rooted in degradable organic nitrogen (N0), which is present at about 10% of total soil nitrogen, and can be broken down into a dry-soil effect-derived fraction (N0q) and a soil temperature increase-derived fraction (N0s). The dry-soil effect-derived fraction is mostly expressed from the end of May to the beginning of June. Therefore, its quantity greatly affects the early growth of paddy rice plants. As we have pointed out in the past, the initial leaching of nitrogen from the seedling box is slow and reaches its maximum amount in mid to late July in rice fields where the seedlings are left to grow in the box. Therefore, if only seedlings are transplanted from the seedling box, nitrogen leaching in the early stage of the field will be insufficient, making it difficult to obtain the initial number of stems. The combined amount of fast-acting fertilizer at transplanting and soil nitrogen due to the dry-soil effect will control the initial growth of the seedlings.

　In order to expect a dry-soil effect, the amount of soil fraction derived from the dry-soil effect is of course important, but it also depends on how much air-dried soil mass is increased in early spring, between tillage and plowing. Plowing should be done as early as possible to increase the proportion of white-dry clods. No matter how large the fraction of soil derived from the dry-soil effect may be, the dry-soil effect cannot be expected if the soil is plowed in late, watered immediately after plowing, and raked immediately after tillage. In other words, rice plants can maintain good nitrogen nutrition conditions throughout their growth by relying on side-row fertilization and soil nitrogen derived from the dry-soil effect in the early stage of rice growth, and relying on soil nitrogen derived from seedling box placement and soil temperature increase effect in the middle and late stages of growth.

　The effects of tillering time and dry soil on soil nitrogen expression and initial stem number are shown in Figure 2. The soil nitrogen content at 6/9, one month after transplanting, and the number of stems at that time are shown in Table 1. In other words, as mentioned above, if tillage is delayed and watering and raking are done immediately after tillage, no dry-soil effect can be expected. In order to expect a dry soil effect, it is effective to accelerate the tillage period and accelerate the drying of the soil surface layer before watering and raking.

3. growth pattern to secure the proper number of rice grains (36,000 grains/m2)

　In order to achieve a high yield, it depends on how to secure the proper number of rice grains and how to increase the ripening rate. 600 kg yield requires about 32,000 grains/m2 of rice. 36,000 grains/m2 is needed to obtain a high yield of 720 kg. If the proper number of paddy grains is secured and a thousand grain weight of 23.0g and a ripening rate of 86% can be achieved, a high harvest is completed. It sounds simple when written in words, but it is not so easy. Farmers are always thinking about what kind of rice they should grow to secure the proper number of rice grains. This is a true test of skill.

　Based on many years of experience, the author has been aiming for high yield with ear-weighted varieties such as Sasanishiki and Koshihikari by increasing the rate of rice maturity (V-shaped rice cultivation) by reducing leaf color in the middle stage of growth to prevent collapse and by limiting the number of paddy per ear without overgrowing the maximum number of stems, although early growth is important. On the other hand, recent high-yielding varieties have been dominated by short, ear-heavy varieties (Haenuki, Setsuwakamaru, etc.), which are more resistant to downfall. These varieties are particularly important for early growth, and the aim is to grow rice with a sense of ear weight by not losing much leaf color in the middle stage of growth (heji-shape rice cultivation) and by thickening the stem mainly through deep water management, etc., with the parent stem as the main body. In other words, there is a growing trend toward high-yield rice cultivation that emphasizes late-season nitrogen nutrition by securing initial stem number with fast-acting fertilizers such as side-row fertilization and maintaining leaf color from the mid-seedling stage onward by leaving the seedlings to the seedling box. The combination of side-row fertilizer application and leaving it to the seedling box is exactly what is expected.

4. proper nitrogen uptake pattern and late stage nitrogen nutrition

　It is important to clarify the relationship between nitrogen absorption patterns of paddy rice and brown rice yield in order to secure an appropriate number of rice grains. Here, we will examine the process of nitrogen absorption in high-yield rice paddies in the Shonai region of Yamagata Prefecture. The Shonai area is one of the best rice-producing regions in Japan, and for more than 40 years, a rice-growing campaign has been conducted in the area, with 60 demonstration fields established at each of the agricultural cooperative branches. Among them, 14 demonstration fields with different yield levels were selected and nitrogen absorption by rice plants was investigated at different times of the year over a two-year period. Figure 3 shows the results of the survey of the demonstration fields and the relationship between nitrogen absorption and brown rice yield since 1965 from the three-factor test conducted at the Shonai Branch.

　According to the data from the three-factor test, there was a linear positive relationship between brown rice yield and nitrogen absorption up to a brown rice yield of about 600 kg per 10 a, as has been pointed out in the past, and a tendency for nitrogen absorption to slow down at higher yields. However, when the absorbed amount of nitrogen in the 14 demonstration fields where soil improvement was emphasized was added, the linear positive relationship between brown rice yield and nitrogen absorption continued up to about 800 kg per 10 a. This is because soil improvement in the demonstration fields has an effect on nitrogen uptake. This was attributed to the effect of soil improvement in the demonstration fields, especially the application of siliceous fertilizers based on soil diagnosis, which stabilized the maturity yield and led to stable yield even when nitrogen absorption increased, thus establishing the above-mentioned relationship.

　Next, the yields of the demonstration fields (14 locations) were divided into two groups: the 700 kg/10 a level (average 727 kg at 7 points) and the 600 kg/10 a level (average 667 kg at 7 points), and the percentage of nitrogen absorption at each time is shown in Table 2. According to the results, the 700 kg/10 a level group absorbed more nitrogen than the 600 kg/10 a level group, and in the nitrogen absorption ratio by time, the amount of nitrogen absorbed after the ear-arrangement period was higher, which is a major characteristic of autumn-successive growth. This is what we expect from the seedling box.

Demonstrated high yield with 1:1 side-row fertilization and seedling box application for total nitrogen

　The Hondate area of Sakata City is located in the center of the Shonai-Atsumi district and has a reputation for being a representative area of high-quality rice production. In this area, three young farmers were asked to set up a test plot with a total of 8 kg/10a (4 kg/10a of side-row fertilizer and 4 kg/10a of seedling box compost) over a period of two to three years from 2020, and conducted a demonstration test using farmer's practice (base fertilizer + additional fertilizer) as a control. This test was conducted in collaboration with Farm Frontier Corporation (Dr. Fujii) as part of the "Smart Agriculture: Soil Preparation Linked Next-Generation One-Shot Basal Fertilizer System. The three young farmers were asked to use the "seedling box leave" system for the first time, and they had no problems and obtained good quality seedlings with high nitrogen and slimy seedlings. The seedlings were grown in 25 boxes of N400-100 at 400 g/box per 10 a. The variety was "Haenuki". The variety "Haenuki" was used.

　Table 3 shows the results of the yield survey conducted in 2020, the first year of the study. According to the results, in each test site, the initial growth tended to be superior to that of the control site (farmer's practice) when side-row fertilizer was applied, and the side-row + seedling box area showed a clear trend toward higher stem quality (culm) and less variation in culm quality, and yield increased by 2 to 14% compared to the control area, achieving a yield of almost 700kg/10a.

6. Conclusion

　The good compatibility of side-row fertilization and leaving the seedling box to the seedling box was clearly demonstrated. Field tests have demonstrated that a fertilizer nitrogen ratio of 1:1 between side-row fertilizer application and seedling box-applied fertilizer is appropriate, considering a total nitrogen fertilizer application rate of 8 kg/10 a. The ratio can be changed according to soil fertility. If a side-row fertilizer applicator is not available, the same can be done by applying a fast-acting fertilizer (e.g., one or two bags of All-14) to the entire field before transplanting. In other words, the initial growth of paddy rice depends on the combined amount of soil nitrogen (dry-soil effect) and fast-acting fertilizer, while the mid- and late-season nitrogen nutrition is supplied by leaving the seedlings in the seedling box and soil nitrogen (nitrogen from the soil temperature increase effect), which provides continuous nitrogen nutrition throughout the entire growth period and leads to high yield. In addition, the box-applied fertilizer is nitrogen only (NK301 is nitrogen and potassium), and phosphoric acid and potassium are also supplied at the same time by combining side-row fertilization and fast-acting fertilizers. The key to a high harvest is to secure the proper number of rice grains (36,000 grains/m2) on a stable basis by making full use of the techniques I have experienced and refined.

Soil and flower - 9th
　　Conditions for Good Soil Chemical Properties - Part 4
　　How the soil retains nutrients

Hokkaido Branch Office, JCM Agri Co.
　Teruo Matsunaka Technical Advisor

　It 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.

1. discovery of nutrient retention capacity of soil

　The 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.

　However, 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.

　Spence gave the farm soil ammonium sulfate, mixed it well, packed it into a glass tube, poured distilled water (H2O) over the top, and analyzed the composition of the seepage water that came out the bottom. The ammonium that should have been added disappeared from the osmotic water, and instead calcium appeared as calcium sulfate. Based on the results of Spence's experiment, Thompson believed that the soil attracted and retained the ammonium and was the first in the world to publish this fact in a paper in 1850.

　Around 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.
　After 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.

　All 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.

2. the carrier of the soil's nutrient retention capacity

　The 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.

(1) Bearer of soil load (negative electricity)

　There are three types of charges in soil: (1) a charge due to structural changes in clay minerals, (2) a charge formed at the terminals of clay minerals, and (3) a charge formed at the terminals of organic matter (humus). Clay minerals are formed when rocks (primary minerals), which are the raw materials of soil, are metamorphosed by physical or chemical weathering to form minerals (secondary minerals) that are different from the original rocks. The basic structure is a sheet of silicon or aluminum, to which oxygen, hydrogen, and other elements are regularly bonded. Here, silicon-dominant sheets and aluminum-dominant sheets are referred to as "silicon-dominant sheets" and "aluminum-dominant sheets," respectively. The load bearer (1) is formed when silicon (four positively charged hands) is replaced by aluminum (three positively charged hands), whose atoms are almost the same size, in a clay mineral crystal, for example, a silicon-centered sheet (Figure 1).

　The four positively charged silicon is balanced by the four positively charged oxygen. However, when it is replaced by aluminum, which has three positive charges, there is a surplus of one loading charge of oxygen. This excess charge is a stable charge that always functions as a loading charge regardless of the surrounding conditions, and is called a permanent charge.

　Both (2) and (3), the bearers of the charge, occur as the pH around the charge increases. pH increase means that hydrogen ions (H+) decrease and hydroxyl ions (OH-) increase. In both cases (2) and (3), hydrogen (H) at the ends of hydroxyl groups (-OH) and carboxyl groups (-COOH) on clay mineral sheets and organic material terminals are attracted to the increased hydroxyl ions and are stripped from the bound oxygen (O) to form H2O This creates a surplus in the load potential, which functions as the load potential of the soil (Fig. 2). In other words, this loading charge is an unstable charge that changes under the influence of pH and is called a mutated charge.

(2) Bearer of positive charge (positive electricity)

　There are three main bearers of positive charges in soil: (1) charges on the terminals of aluminum-based sheets, (2) charges on the terminals of organic matter, and (3) charges on clay minerals (oxides of iron and aluminum) in soil that has been weathered. All three charges are mutated charges that occur as the pH of the surrounding environment decreases, meaning that hydrogen ions (H+) increase as pH decreases. The basic mechanism for the generation of positive charge is the same for (1), (2), and (3): the hydroxyl group (-OH) and carboxyl group (-COOH) at each terminal attract hydrogen ions (H+) that increase due to the decrease in pH to form oxonium ions ( -OH2+), which functions as a positive charge (Figure 3).

3. permanent charge and exchangeable aluminum

　The permanent loading charge pointed out earlier is not affected by pH. Therefore, it functions as a loading charge even when the pH decreases due to acidification, thus stably retaining aluminum ions (Al3+) that appear under acidic conditions as exchangeable cations. Non-allophenolic black soil, introduced in Part 7 of this series, has this type of loading potential and was able to retain much of the exchangeable aluminum that causes acid injury to crops. This is the reason why acid damage occurred in corn.

　On 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.