Agriculture and Science 2022/4

Smart Agriculture Linked Soil Preparation, Next Generation
　High-yield technology for staple rice through a one-shot variable basal fertilizer application system

Chairman of the Board, Farm Frontier Inc.
Visiting Professor, Faculty of Agriculture, Yamagata University
Hiroshi Fujii

1. current rice crop productivity issues

　Figure 1 summarizes the current issues in rice cultivation. Factors that lead to increased variation in growth and yield among and within fields, as well as lower yield and quality, include (1) suppression of early growth (dash start) and (2) wilting in the late growth stage (reduced endurance). Factors that suppress the dash start include low seedling quality, shortened vegetative growth period, progressive reduction, and reduced nitrogen fertilizer application, resulting in insufficient number of stems (low yield), low stem quality (collapse), insufficient root mass (low yield), and increased internode length (collapse).

　Factors contributing to low endurance include weather factors (e.g., high temperatures), low soil fertility, low nitrogen nutrition, insufficient root mass, insufficient silicon, and water management, resulting in late-season wilting, reduced number of leaves (wilting), poor ripening, and lower yield and quality. To solve these problems, it is necessary to improve the dash to ensure early growth and the endurance to control wilting in the late vegetative stage.

　Negative factors for endurance in terms of nitrogen nutrition in the leaf blade can be considered as follows. A decrease in nitrogen concentration in the lower leaves (increased senescence pressure in the leaf blade) will require nitrogen from the rice plant, in which case translocation from the lower leaves to the upper leaves will be enhanced. If the wilting of the lower leaves is caused by nitrogen translocation to the upper leaves due to nitrogen deficiency, late wilting occurs, resulting in lower yield and quality. This tendency is more pronounced in fields with low soil fertility and in high temperature years.

　On the other hand, in rice paddies with high soil fertility, the nitrogen supply is derived from soil fertility, and the concern about a decrease in nitrogen concentration in the lower leaves is considered to be low (low senescence pressure). However, in rice paddies with poor early growth in recent years, it is assumed that a decrease in nitrogen concentration in the lower leaves occurs early after the ear setting stage due to insufficient root mass.

2. development of high-yielding staple rice technology based on smart agriculture-linked soil fertility and next-generation base fertilizer application system with one-shot variable fertilizer application

(1) Strategy for realization

　As shown in Figure 2, the strategy to achieve this is to develop a technology to achieve labor-saving, low-cost, and high-yield crops by combining side-row fertilization (early securing of initial stem number, improvement of culm quality, and improvement of culm leaf fullness) and "drip effect" (Figure 3) by leaving the seedling box to the seedling box, and leaving the box to the seedling box (continuous nitrogen supply to leaf blade and improved leaf maturation) and soil preparation linked with information to deal with endurance, as shown in Figure 2. The technology has been developed to reduce variation in growth and yield between and within fields and to realize labor-saving, low-cost, and high-yield production by using a combination of siliceous materials and rice straw rotting (Fig. 3).

　The response of paddy rice plants is to secure the required number of stems (lower division) at an early stage by dashing off the seedlings with side-row fertilizer application and leaving the seedling box (drip effect), which enables sufficient growth adjustment (deep watering and drying) (securing heavy stems with a dry matter weight per stem). In addition, it will ensure efficient soil fertility and a system that improves endurance in the late growth period (suppression of late wilting and maintenance of nitrogen nutrition) through nitrogen supply by placing seedlings in a box. The development of these technologies will enable the reform of the current rice cultivation system, which is vulnerable to weather disasters (high temperatures, etc.) due to poor early growth and root elongation, delay in securing the required number of stems, inadequate timely response to growth adjustment such as drying out, resulting in suppressed root mass, and insufficient nitrogen supply in the latter half of growth, which together with reduced leaf color and withering, make the rice vulnerable to weather disasters. This can lead to a change in the system that is vulnerable to weather disasters (e.g., high temperatures).

(2) Strategies linked to smart agriculture (creating plots with less variation)

　The current system for reducing variation in growth and yield between and within fields is based on growth data captured by drone sensing and variable fertilization (fertilizer application by unmanned helicopter and base fertilization by GPS-equipped broadcaster in the following year) (based on the assumption that there is variation between and within fields). However, this method requires a large amount of fertilizer to be applied every year, and the number of droughts is limited. However, this method requires drone sensing and variable fertilization every year, which is costly and time-consuming.

　Therefore, as a next-generation system to reduce variation in growth and yield between and within fields, we will develop a "less variation field" by combining (1) soil preparation (siliceous materials, rice straw rotting) linked with map information and sensing image information, and (2) fertilizer application system linked with map information (soil fertility, dry soil effect). The system is also used in conjunction with a fertilizer application system based on map information (soil fertility, dry soil effect).

0Information-linked soil preparation concept
　Based on information from soil analysis and questionnaires (map information), we implement silicic acid materials and rice straw rotting systems for each field, select and concentrate soil preparation sites between and within fields based on sensing image data, and optimize the selection of silicic acid materials and spraying methods using an information system. We will reduce variation in soil fertility, reduce reduction of reduction, and promote early growth and suppress late wilting.

Concept of 0-information-linked fertilizer application
　By varying the amount of nitrogen applied to each field based on the evaluation of the field soil fertility (regional variation) and dry-soil effect (annual variation), which are factors that cause variation in the soil nitrogen absorbed by paddy rice, it is possible to reduce the variation in soil fertility from field to field. Specifically, variable fertilizer application is implemented for each field by optimizing the nitrogen amount of side-row fertilizer (fast-acting N: equivalent to base fertilizer) based on information (map information) such as field soil fertility (regional variation) and dry-soil effect (annual variation), and optimizing the nitrogen amount of seedling box application (slow-acting N: equivalent to additional fertilizer) based on soil fertility, variety, yield target, and weather conditions. The amount of nitrogen and fertilizer type are determined for each field based on soil fertility, variety, yield targets, and weather conditions.

Fertilizer "run-out" evaluation, inter-field and intra-field soil fertility evaluation by 0-sensing
　Optimizing the use of additional nitrogen by constructing a system for determining fertilizer use based on information such as image diagnosis using drone sensing, growth speed after transplanting, and weather conditions (temperature and hours of sunlight); understanding the variation among and within fields; and responding to variable fertilizer application for soil preparation by understanding the reduction of We are also working to reduce variation among and within fields.

　Table 1 shows the actual information processing using the information-linked fertilizer application system. (1) Secondary information is created from the primary information, (2) the nitrogen amount of side-row fertilizer (equivalent to base fertilizer) is determined from the primary information (soil fertility) and secondary information (dry soil effect), and (3) the amount of nitrogen applied to the seedling box (equivalent to additional fertilizer) is determined from the primary information (variety, soil fertility, weather, yield, etc.).

Demonstration and research on high-yield staple rice technology based on smart agriculture-linked soil fertility and next-generation base fertilizer application system with one-shot variable fertilizer application

(1) Testing method

　We conducted a demonstration test in 2020 and 2021 using rice paddies with high soil fertility, setting up a control area with farmer's practice and a test area with side-row fertilization and seedling box-applying.
(1) Sample type: "Haenuki
(2) Test plots: Control and test plots were set up in 30a plots (two plots).

Composition of 0 test area
Control area (farmer's practice)
　Field A (2020, 2021): total basal fertilizer ⇒ fast-acting
　　Nitrogen (55%): slow-release nitrogen (45%)
　Plots B (2020) and C (2020, 2021): Base fertilizer nitrogen, fertilizer nitrogen ⇒ fast-acting nitrogen
　Plots A and C (2021): Soil preparation (60 kg/10a of siliceous material (steel slag) applied)

Test area (side-row fertilizer application + seedling box)
　Plots A, B, and C: Side-row fertilization ⇒ fast-acting nitrogen
　Plot A: "Seedling box leave" 2020 ⇒ LPs100 (100 types), 2021 ⇒ LPs100s (80 types)
　Plot B: "Seedling Box Leave" 2020 => LPs100s
　Plot C: "Seedling Box Leave" 2020, 2021 ⇒ 100s of LPs
　Plots A, B, and C: Soil preparation by information use (application of 60 kg/10a of siliceous material (steel slag))

(2) Weather conditions

　The ear emergence period was August 3-4 in 2020 and July 30-31 in 2021. Average temperatures were as high as 27°C from late August to early September in 2020, and more than 27°C from late July to early August in 2021, with abnormally high temperatures of 29°C especially in early August (Figure 4).

　In 2020, sunshine hours were less than normal from late July to mid-August and more than normal from late August to early September, while in 2021, sunshine hours were more than normal from late July to early August and less than normal from mid-August to late August (Figure 5). In both years, high temperatures after ear emergence caused the vigor of the rice plants to be easily depleted (i.e., summer loss).

(3) Test results

(1) Evaluation of start-up

(1) Evaluation of initial growth
　Early growth (number of stems per m2) and grass height x number of stems per m2 x leaf color (≈ nitrogen uptake) at 27 to 29 days after transplanting tended to be higher in the test area in both 2020 and 2021 compared to the control area (farmer's practice). Securing the number of stems at an early stage will ensure the first stage of primary offshooting (vigorous stems) at the 3rd to 6th nodes. It has been pointed out that the primary offshoots at nodes 3 to 6 are more frequently produced than other offshoots, have a higher effective rate to the ear, and have a heavier weight of polished rice per ear. Early securing of early offshoots will ensure growth control (deep watering and drying), suppress weak stems, and strengthen the culm quality by thickening the strong stems secured early.

　In recent years, there have been many cases of poor early growth and delayed growth adjustment (drying out), resulting in insufficient root mass due to inability to dry out the seedlings. To get a head start, it is an important strategy to secure strong stems at an early stage by applying side-row fertilizer and leaving the seedlings in the box (drip effect) to allow time for subsequent growth adjustment.

(2) Stem quality evaluation
　Compared to the control (farmer's practice), there was a trend toward higher stem quality (culm) fullness (thickness) and less variation in culm in the side-row + seedling box test plot (Table 4). The results in 2020 showed that one-stem weight was higher in the soil-planted test plot than in the non-soil-planted test plot, indicating the effect of silica application. In 2021, the control also applied silicon material, so the one-stem weight tended to be higher than in 2020, but the test area tended to be better than the control area, indicating that "side-row fertilization plus seedling box placement" was effective in improving stem quality in both years.

(2) Endurance evaluation

(1) Evaluation of leaf color during the ripening stage
　Leaf color in the test plot at August 22, 2020 (18 days after ear emergence) was similar to that of the control plot. The difference in leaf color between the first and second leaves tended to be smaller in the test plot than in the control plot (Table 5).

　In 2021, the average temperature after ear emergence was higher than 29°C, so there is concern about wilting of nitrogen nutrition in the rice body.
The annual growth rate of the control was about 1.5 times higher than that of the control. According to the color trends of the top three leaves at approximately weekly intervals since ear emergence (Table 6), the control
In the case of the first two leaves, there is a large decrease in leaf color, especially in the third leaf from the top (the lower leaf), and withering occurs, and the later leaves are more susceptible to the disease.
The growth pattern is considered to be a wilted growth pattern, with high senescence pressure in the lower leaves and nitrogen translocation to the upper leaves, resulting in a wilted nitrogen nutrition of the entire rice plant body. On the other hand, the test area showed less decline in leaf color, and the lower leaves (the third leaf from the top) also maintained their color, resulting in less senescence pressure on the lower leaves and nitrogen nutrition of the entire rice body.

(2) Evaluation of climbing ability (Figure 6)
　According to the relationship between the number of paddy per square meter and the yield of polished rice grains, the yield of polished rice grains per square meter tended to be higher in the test area than in the control area. In addition, the silicon material applied to the test area (steel slag) tended to increase the yield of polished rice grains per square meter of rice area compared to the control area.
The ratio of the number of milled brown rice grains to the number of paddy grains per unit of rice tended to be high.

(3) Evaluation from yield components, quality/taste and nutrient absorption (Table 7)

　In terms of yield components, the number of rice grains per square meter tended to be higher in the test area than in the control area, and the number of rice grains per square meter increased with the application of silicic acid. The number of polished brown rice grains (number of brown rice grains over 1.9 mm), an indicator of rice maturity, tended to be higher in the test area (side strips + seedling boxes) than in the control area. The combination of silica material (steel slag) tended to further improve the maturity and yield.

　Yield was also higher in the test area than in the control area (farmer's practice). The combination of silica material (steel slag) tended to further improve the ripening and yielding performance.

(4) Evaluation of labor savings, low cost, yield, and profitability

0 Workability evaluation（per 10a)
　In the control (farmer's practice), the number of times fertilizer was applied in the rice paddies averaged three times: once in the A (one shot application of all base fertilizer), three times in the B (base fertilizer + two additional fertilizer applications), and five times in the C (base fertilizer + four additional fertilizer applications). On the other hand, in the test area (side-row fertilizer application + seedling box placement), each field received only one application, which was more labor-saving than in the control area (farmer's practice).

Evaluation of 0 cost
　The cost of fertilizer application and soil preparation per 10 a was 4,766 yen, 5,305 yen, 4,751 yen, and 4,941 yen per 10 a in the control, B, and C, respectively, with an average of 4,941 yen. On the other hand, in the test area, the cost was 4,298 yen for A, 4,055 yen for B, 4,208 yen for C, and 4,187 yen on average, which were lower than those in the control area (farmer's practice). In the test plots where soil preparation was used in combination, each plot increased by 3,600 yen, with an average cost of 7,787 yen.

0Yieldability (10a yield)
　In the control area (farmer's practice), yields were 626 kg, 677 kg, and 657 kg per 10 a, respectively, averaging 653 kg. On the other hand, in the test area, A699 kg, B679 kg, and C682 kg were produced, averaging 687 kg. The average weight of the test and silica material plots was 708 kg (A723 kg, B705 kg, and C697 kg). Compared to the control (farmer's practice), the test area yielded 34 kg more, and the area where the test area was combined with silicic acid material yielded 55 kg more.

0Evaluation of quality and taste (brown rice protein content)
　Quality (grain yield) and brown rice protein content were almost the same in the control (farmer's practice), test, and test + soil cultivation areas.

0 Profitability evaluation
　The average of the three fields was 125,726 yen in the control area (farmer's practice), which was 120,432 yen in A, 130,095 yen in B, and 125,658 yen in C. In the test area, the average of the three fields was 135,502 yen in A, 131,745 yen in B, and 133,192 yen in C. In the test area plus soil preparation, the average of the three fields was 133,146 yen in A, 136,702 yen in B, and 133,192 yen in C. In the control area, the average of the three fields was 133,146 yen in A, 133,146 yen in B, and 133,192 yen in C. In the test area and soil preparation area, A was 136,702 yen, B was 133,345 yen, and C was 131,592 yen, averaging 133,880 yen for the three plots. Compared to the control (farmer's practice), the test plot had an increase of 7,420 yen, and the plot where the test plot was combined with soil cultivation had an increase of 8,154 yen.

　Therefore, the profit will increase by approximately 8,000 yen per 10a, 80,000 yen per 1 ha, 2.4 million yen per 30 ha, 8 million yen per 100 ha (large corporations), and 80 million yen per 1,000 ha (region) by "side strips + seedling boxes".

5) Variability evaluation of paddy rice growth (Table 9)

　According to the drone sensing data of NDVI with multiple cameras (Table 9), the variation of NDVI at 29 days before ear emergence, 17 days before ear emergence, and at the ear emergence stage in plots A, B, and C was lower in the test plot than in the control plot, indicating that there was less variation in the growth of the area. The variation in NDVI tended to be lower in the test area than in the control area at 29 days before ear emergence and 17 days before ear emergence.

Summary

The use of map information (soil, work, and weather) and sensing information in conjunction with smart agriculture will enable the development of a new type of agricultural technology that is more efficient, efficient, and effective.
　Soil fertility (e.g., silicic acid materials, rice straw rotting, etc.) and soil fertility and soil fertility in each field (or site within a field).
　A system for setting the amount of nitrogen for side-row fertilizer application based on dry-soil effect information (map information) has been established.

The combination of "side-row application (equivalent to base fertilizer) and box-applied fertilizer (equivalent to additional fertilizer)" as a next-generation fertilizer application system.
　In the start-dash part, which is a problem of paddy rice cultivation, side-row fertilizer application + leaving it to the seedling boxes (drip effect), and the endurance of rice cultivation.
　The power part is handled by the seedling box.

High (thick) dry matter weight per tree due to early stem number and early stem number by side-row fertilizer application
　stems (better culm quality, higher culm leaf fullness), and less variation in culm length.

The endurance was also improved by the maintenance of leaf color during the ripening period, the small difference in leaf color between the first and second leaves, and the "seedling box cover.
　The nitrogen is supplied little by little from the "Se" and the aging pressure is low because the rice absorbs the nitrogen little by little.
　Less wilting of the lower leaves, and a milled brown rice grain number yield (brown rice of 1.9 mm or more), which is an indicator of final maturity
　The "side-row + seedling box-allowed" method tended to outperform the control method (farmer's practice) in the "side-row + seedling box-allowed" area.

Yield was also higher in the "side-row + seedling box-allowed" area than in the control area (farmer's practice: base fertilizer + additional fertilizer, one-shot application of base fertilizer).
　The combination of silica material (steel slag) tended to have better The combination of silica material (steel slag) tended to have better ripening and yield performance.
　It was a direction.

The following three points can be evaluated: workability in terms of the number of fertilizer applications, cost in terms of the cost of fertilizer application, and yield (profit) in terms of profitability.
　The "side-row + seedling box-applied" fertilization system was more effective than the control system (farmer's practice: base fertilizer + additional fertilizer, one-shot application of base fertilizer).
　It was found to be superior in terms of labor saving, low cost, and high yield.

No Soil - 10th Summary of Good Soil Conditions
　　-Any soil will do.

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

　It 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.

1. what is soil preparation in the first place?

　When 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.

　I have an indescribable sense of discomfort with this fixed concept of "soil cultivation. If it were that simple, I would think that soil with poor crop production would soon disappear from the world. In short, it is only a matter of applying compost.

　I 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.

2. does good soil guarantee a high yield?

　In 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.

　Suppose 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.

　Crop 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).

3. soil is one of the factors that determine the crop productivity of farmland

　In 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.

　The 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.

　The 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.

4. the story of "the man who planted the tree" - any soil can always be made better.

　I 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.

　In particular, essential improvements in the physical properties of the soil cannot be achieved overnight by simply saying, "It will get better if you apply compost. It will probably not be possible unless the improvement measures are continued from generation to generation, from parents to children to grandchildren. The question is whether we will be able to sustain our efforts to improve the situation until then without giving up and without giving up tirelessly.

　There 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 Elzéard Bouffier, who planted trees on the barren soil of Provence, restored forests and rivers, and even restored the moisture to people's hearts.

　Selflessly 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.

　What 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.