Agriculture and Science 2022/5

Improving fertilizer efficiency and saving energy in tea gardens
　　　　　　　　　　　Establishment of one-row fertilizer application technology

Shizuoka Prefectural Institute of Agriculture and Forestry Technology
Tea Research Center, Department of Tea Environment Adaptation Technology
　Researcher Takanori Ono

Introduction

　In the fertilizer management of tea plantations, it is important to improve the yield and quality of tea while reducing the environmental burden.

　Local fertilizer application technology has been developed as a technology that can reduce the amount and frequency of nitrogen fertilizer application due to its high utilization of fertilizer nitrogen.

　The localized fertilization technique here refers to a method of applying fertilizer in the soil below the canopy of the tea tree in the form of a tube at a depth of approximately 5 to 25 cm below the ground surface using a special fertilizer applicator. Therefore, per 10a, about 1,850 holes are dug and fertilizer is applied. The fertilizer is then applied in a cylindrical shape to each hole, which takes about 3 hours even when a special fertilizer application machine is used.

　Therefore, with a view to mechanization to improve the efficiency of fertilizer application (mainly through the development of attachments for riding-type management machines), we conducted tests from FY2018 to FY2020 on the "establishment of strip fertilizer application technology to improve the efficiency of fertilizer application and save labor in tea gardens," aiming first to establish a technique to apply coated fertilizer in a streaked pattern at rain-fall areas. The results are reported here.

2. Testing Method

1) Test site: Yellow soil at the Shizuoka Prefectural Agricultural and Forestry Research Institute's Tea Research Center 2) Prototypes/variety: Chama 'Yabukita' (planted in 1988)
(3) Test fertilizers and materials: Ecolong 426-140, Super NK Ecolong 203-180, Double
　　　Quick NN660 (Jcam Agri Co., Ltd.)
(4) Test composition: In this test, Ecolong 426-140, a 140-day nitrogen-eluting type, was applied in the spring to the row-applied area, and Super NK Ecolong 203-180, a 180-day nitrogen-eluting type, was applied in the fall to the row-applied area. In late March, the two areas and the
The fertilizer, Double Quick, a phosphorus-nitrite potassium fertilizer, was also applied to the entire area (Table 1).

　The position of fertilizer application is shown in Figure 1.

(5) Test size: 9.0 m2 (5.0 x 1.8 m) per plot, 3 replicates per plot
(6) Survey items and methods:
　a) Yield component study (20 x 20 cm frame plucking): first and second teas
　(b) Fresh leaf yield: first tea, second tea, autumn/winter tea
　c) Nitrogen content of plucked buds (NC analyzer): first tea, second tea, autumn/winter tea
　(d) Soil analysis: rainfall, between the beds of each test plot on July 21, 2020.
　　Soil samples were taken from the fall (4 soil samples per plot from 0 to 15 cm deep were collected and mixed with an auger), and
　　Analysis was conducted for pH, EC, humus, total nitrogen, inorganic nitrogen, dietary phosphate, CEC, and exchangeable bases.

3. Summary of results

(1) The results of the frame picking survey showed that in the second tea of the third year of the test, the number of picked buds in the spring and strip-fertilized areas and the number of picked buds in the fall and strip-fertilized areas were higher than in the spring and strip-fertilized areas.
　 The number of buds and the number of buds removed were higher than those of the control (Table 2).

(2) Fresh leaf yield tended to be higher in both the spring and fall row fertilization areas than in the control area throughout the year.
　　The yield was significantly higher in the first year than in the control. In the second year of the trial, the yield of the fall/strip fertilization area was significantly higher than that of the control area, especially for the first tea leaves, and the yield of the fall/strip fertilization area was significantly higher than that of the control area.
　For the second tea, yields were significantly higher in the spring- and autumn-row-fertilized areas than in the control area in the first year of the test.
　The number of the "new" products became larger (Table 3).

(3) The nitrogen content of the picked buds tended to be higher in the first tea leaves than in the control leaves in both the spring and fall treatments.
　　The results were significantly higher in the spring and row application in the second year of the study, and in the fall and row application in the third year of the study.
　　to higher (Table 3).
(4) Nitrogen deprivation calculated from fresh leaf yield and nitrogen content of plucked buds was higher in the fall/strip fertilizer application zone versus the fall/strip fertilizer application zone in the first tea leaves.
　　The number of fertilizers applied to the second tea leaves tended to be higher in both the spring and fall row-applied areas.
　　Table 4).

(5) The results of the soil analysis are presented in Table 5.
　　The pH of the tea plantation soil was measured in both the spring and autumn soil application areas, and in the inter-village area.
　　It was in excess.
　　　Exchangeable lime content also exceeded the standard for soil improvement in both the spring and fall soil application areas.
　　The rainfall area was short, whereas the rainfall area was in excess.
　　　Based on the above, the conventional amount of bitter lime (100 kg/10a) does not need to be applied for strip fertilization.
　　The number of fertilizer applications could be reduced by supplemental application to the rainfall area at times. In addition, the use of
　　The amount of inorganic nitrogen in the rainfall area was high in both the spring and fall row fertilization areas, and efficient nitrogen absorption was achieved.
　　The results of the study suggested that the number of

(6) These results show that both spring and fall row fertilization increased the yield of fresh leaves and the nitrogen content of plucked buds of first tea leaves.
　　The results suggest that an increase in the prevalence of the disease can be expected. In particular, the fall row fertilization was more effective than the spring row fertilization in increasing the percentage of one
　　It was expected to increase the yield and nitrogen yield of the second tea plant.
　　　The results of soil analysis suggest the need to consider the amount of bitter lime applied when applying soil compost.
　　The first time the project was completed, the project was completed in the middle of the year.

Summary

　In this study, a test plot was set up in which 30 kg N/10a of a cover fertilizer was applied in late February or late August to a depth of about 5 cm in the rain-fall area of the tea plantation, and 10 kg N/10a of a fast-acting fertilizer was applied above the canopy in late March.

　As a result, there was a trend of increased yield of fresh leaves and increased nitrogen content of plucked buds of first tea throughout the year in both test areas compared to the conventional area. In particular, the late-August strip fertilization tended to increase the yield and nitrogen deprivation of the first tea leaves more than the late-February strip fertilization. The results of soil analysis suggested that it is necessary to consider the amount and position of application of bitter lime when applying soil fertilizer.

　However, care should be taken when applying fast-acting fertilizers to the entire area, because if rainfall after application is low, fertilizer nutrients may not be fully absorbed at the right time.

　In order to spread the technology of strip fertilizer application in the future, it is necessary to continue further studies on machine development and work efficiency. In particular, in terms of machine development, it would be easier to spread the technology if it were developed as a riding-type attachment, considering cost and work efficiency.

Fertilizer-regulated fertilizer in two-row barley.
　　　　　　　Total basal fertilizer seeding trench application method using

Oita Agriculture, Forestry and Fisheries Research and Guidance Center
Agricultural Research Department, Paddy Field Agriculture Group
Rika Kiyota

Introduction

　Oita Prefecture has been working to expand the use of direct seeding of paddy rice in dry rice paddies1) , and has developed a technology for applying fertilizer in the seeding furrow using a drill seeder used for wheat cultivation (hereinafter referred to as "drill seeder seeding furrow application technology"). This technology has enabled the general use of the drill seeder in both rice and wheat crops. (2012) reported that full basal application of a controlled-release fertilizer resulted in higher yields than conventional basal application of a conventional fertilizer.2) However, in recent years, the use of a drill seeder in the seeding furrow of wheat has been widely criticized for its lack of efficiency. However, in recent years, low temperatures have persisted after wheat sowing in some years, and there was concern that the initial growth of wheat could not be ensured with only full basal application of a fertilizer with controlled fertilizer.

　Therefore, we investigated the possibility of improving the yield and quality of wheat by applying all the base fertilizer with a prototype fertilizer that combines a fast-acting fertilizer and a regulated fertilizer using the drill seeder seeding furrow application technique that we developed.

2. Methods

　The trials were conducted in paddy fields (soil type: clay loam) at the Oita Prefectural Agriculture, Forestry and Fisheries Research and Guidance Center (8 m elevation, Usa City, Oita Prefecture) for three years from 2018 to 2020 sowing.
　The test variety was Nishinohoshi, a two-row barley.

　The composition of the test plots and seeding times are shown in Table 1. The test plots were divided into two types: a total basal application and a conventional partial application. In the total basal application, two types of granular compound fertilizers with different proportions of fast-acting and controlled-release fertilizers were applied in the seeding furrows and on the entire surface, respectively, for two replications in each test plot. Fertilizer materials were provided by JCAM Agri Co., Ltd. and the prototype fertilizers were formulated at the Oita Prefectural Agriculture, Forestry and Fisheries Research and Guidance Center.

　　The trial fertilizers consisted of ammonium sulfate as a fast-acting fertilizer and sigmoidal-coated urea LP-coated 20-day type (hereinafter referred to as "LPS20") as a controlled-release fertilizer. Two types of fertilizers were tested: a fast-acting fertilizer (fast-acting: controlled-release type) = 3:7 (hereinafter referred to as "Prototype Fertilizer N3"), which was applied as a priority fertilizer in the allotment, and a fast-acting fertilizer (controlled-release type) = 5:5 (hereinafter referred to as "Prototype Fertilizer N5"), which was applied in the same ratio as in the conventional allotment. In the conventional application, 5 kg of base fertilizer, 2 kg of compost, and 3 kg of ear fertilizer were applied per 10 a. In the conventional application, 5 kg of base fertilizer, 2 kg of compost, and 3 kg of ear fertilizer were applied per 10 a. The fertilizer N3 was applied to the entire surface of the crop.

　Base fertilizer was applied on the sowing date, anthesis fertilizer at the 3- to 4-leaf stage of two-row barley, and ear fertilizer at the 2- to 5-mm length of young ears. In each test plot, phosphoric acid and potassium were applied at a rate of 22.9 kg/10a of phosphorus and 13.3 kg/10a of potassium chloride after pre-plowing.
　In the seeding trench fertilizer application area, after the bed was erected, the compaction wheel of the drill seeder was removed and the soil covering device was lifted and fixed, after which the base fertilizer was manually applied to the seeding trench and the soil was covered. In the all-fertilizer-applied area, the base fertilizer was applied by hand to the entire surface of the field after the bed was erected, and the drill seeder was used for seeding, soil covering, and soil compaction, in that order.

　Two sowing periods were set: mid-November to early December, which is the optimum sowing period in low elevation areas of the prefecture ("optimum sowing"), and mid-December to late December ("late sowing"), which is a later sowing period for large-scale management operations.
　To investigate the nitrogen leaching rate of LPS20, a non-woven cloth containing 1 g of the fertilizer stock was buried at a depth of 10 cm from the ground surface in the test plots on the day of fertilizer application, and sampled 7 to 10 times until harvest. In each of the three years tested, three replications were applied, and nitrogen analysis of the samples was performed by the Fertilizer Research Laboratory of JCAM Agri Co.
　The soil temperature of the field was measured at a depth of 10 cm from the soil surface at one-hour intervals between fertilization and harvesting using a temperature recorder (Model TR-52S Ondotori Jr. manufactured by T&D Co.

3. results

(1) Difference in growth progress between seeding furrow fertilization and conventional partial application

　Fertilization methods and results of growth studies are shown in Tables 2 and 3.

　In 2020, the number of stems in the fertilizer application area tended to be lower than in the conventional area in both the early and late seeding areas. In 2020, leaf color in the N3 and N5 compartments became darker from 120 days after fertilizer application (Figures 1-1 and 1-2), confirming the leaching of nitrogen from the fertilizer with controlled fertilizer effect.

　Culm length at maturity was similar to or slightly lower than that of the conventional partial application in both the timely and late sowing treatments, but ear length was slightly longer when the prototype fertilizer was applied in the seeding furrows than when the fertilizer was applied over the entire surface. The number of ears, like the number of stems, was lower when the seeding furrows were fertilized with the prototype fertilizer. However, in the 2019 sowing, strong winds and low temperatures before ear emergence caused sterile ears in both full- and late-seeding, and later ears occurred more frequently, resulting in a higher number of ears.
　The percentage of late ears was higher in the late sowing and in the N3 trial fertilizer, where the proportion of fertilizer with regulated fertilizer was higher in the sowing furrow application.

(2) Yield difference between seeding furrow application and conventional partial application

　The results of the yield and quality surveys are shown in Tables 4 and 5.

　In the timely seeding, when comparing the full application of the prototype fertilizer and the seeding trench application, the yield was higher in the seeding trench application except in the N3 plot of the prototype fertilizer in 2018 and 2019. Furthermore, when comparing the type of fertilizer applied in the seeding furrows, the yield was higher in the N5 plot with the prototype fertilizer than in the N3 plot with the prototype fertilizer, and the yield was almost the same as in the conventional partial application plot.
　In the late seeding, the yield was higher in the seeding trench application compared to the full application of the prototype fertilizer and the seeding trench application. Furthermore, when comparing the type of fertilizer applied in the seeding furrows, yields were higher in the prototype fertilizer N3 than in the prototype fertilizer N5, except in 2018, when yields were generally similar to those in the conventional partial fertilizer application.

(3) Trends in nitrogen elution of LPS20

　The nitrogen leaching of LPS20 buried in the test plots is shown in Figures 2-1 and 2-2.

　The cumulative leaching rate of nitrogen began around the juvenile ear differentiation stage (early January) in the optimum sowing, and more than 801 TP3T was leached by the beginning of internode elongation (mid-April) in the 2018 sowing and by the juvenile ear formation stage (early March) in the 2020 sowing (Figure 2-1). In the late sowing, nitrogen leaching began around the juvenile ear differentiation stage (mid-January), and more than 80% was leached after the flowering stage (late April) in the 2018 and 2019 sowing, and by the earburst stage (late March) in the 2020 sowing (Figure 2-2).

　The nitrogen leaching rate by the elapsed days after burial showed that the nitrogen leaching began to increase around 60 days after burial for both timely and late seeding, with the highest leaching around 120 days after burial for 2018 and 2019 seeding at 251 TP3T or higher, and the highest leaching around 100 days after burial for 2020 seeding at 371 TP3T or higher. The 2020 seeding had the highest elution of 37% or higher around 100 days after burial.
　These results indicate that LPS20 leaches nitrogen from about 60 days after burial (early January for optimum seeding and mid-January for late seeding), and that LPS20 has a fertilizing effect as a runoff fertilizer and ear fertilizer.

Consideration

　In this study, a total basal fertilizer application method with different ratios of fast-acting fertilizer and controlled-release fertilizer was examined for general use of the drill seeder seeding furrow fertilization technique developed for direct seeding of paddy rice in dry rice paddies in wheat cultivation.
　Nitrogen leaching of LPS20, which was used as a trial fertilizer with regulated fertilizer efficacy, began around 60 days after embedding, and the highest nitrogen leaching occurred around 120 days after embedding in the 2018 and 2019 seedings and around 100 days after embedding in the 2020 seeding, depending on the year, but its effectiveness as a batch fertilizer or ear fertilizer was confirmed.

　The reason for the earlier nitrogen leaching in LPS20 sown in 2020 compared to the other two years is that nitrogen leaching in LPS20 depends on soil temperature, and the daily average soil temperature from early March to late March in 2020 was 0.2 to 2.5°C higher than that in the three years, which causes a difference in nitrogen leaching. This is thought to have resulted in faster nitrogen leaching (Figure 3).

　The effect of the prototype fertilizers on the yield of two-row barley was considered to be affected when the proportion of ammonium sulfate in the fast-acting fertilizer was low, as in the N3 plot, because the yield was not sufficient to ensure a sufficient number of offshoots by the young ear formation stage. In particular, the warmer-than-normal winter in the 2019 and 2020 sowing periods accelerated the growth of two-row barley, and sufficient fertilizer application in the first half of the growing season was considered necessary.
　On the other hand, the prototype fertilizer containing ammonium sulfate and LPS20 at a ratio of 5:5 produced yields comparable to those obtained with the conventional partial application when sown at the right time. However, in the case of late seeding, nitrogen leaching of LPS20 peaks from late March to mid-April, resulting in an increase in late ears and a decrease in quality.

　Based on the above, it was considered possible to use the total basal seeding furrow fertilization method for two-row barley by using a fertilizer with a 5:5 ratio of ammonium sulfate to LPS20 and seeding in mid-November to early December.
　When the prototype fertilizer used in this study was applied to wheat, which has a later ear emergence and ripening period than barley, the nitrogen release period of LPS20 and the timing of wheat fertilizer application could be expected to be almost identical.

Acknowledgements

　We would like to express our sincere thanks to Mr. Kawakami and Mr. Tsuchiya of the Kyushu Branch of JCM Agri Co., Ltd. and Mr. Tanaka of the Fertilizer Research Laboratory of JCM Agri Co. for providing the trial fertilizer and conducting the nitrogen analysis of the LPS20 leaching test.

works cited

(1) Oita Prefecture guidelines for direct seeding of paddy rice in dry rice paddies. 2020.
2) Urano, K. 2012.Growth, yield and quality of naked barley in the seeding furrow of total basal application of fertilizer with regulated fertilizer.
　Effects on the JSAZ-Chubu Shuroku 52.

Earthly things - 11th
　　Compost emerged as a nutrient transfer material.
　　-Considering how to replenish nutrients...

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

　Starting 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.

1. nutrient replenishment is necessary to maintain soil fertility

　It 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.

　How 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.

2. compost conceived as a nutrient transfer material

　The 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.

　European 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.

3. intensive crop rotation before the advent of chemical fertilizers

　In the early days of crop rotation in Europe, farmland was simply divided into two plots, one of which was used for crop cultivation and the other was left to recover the nutrients in the soil naturally by taking a break from crop cultivation (called "fallow"). Later, it developed into the three-field system and the grain-planting system, culminating in the Norfolk farming method (Fig. 1).

　Earlier crop rotations also used manure from livestock grazing on common land or permanent pasture. However, keeping livestock on pasture or grassland had the disadvantage that the collection rate of livestock manure excreted from the pasture or grassland decreased. In addition, the growth of wild grasses and pastures declines during the fall and winter, making it difficult to secure sufficient forage to overwinter livestock.

　The 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.

　There 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.
　The 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).

4. Japanese View of Composting: Tradition of the Supremacy of Mature Compost

　Rice 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).

　In 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.