Agriculture and Science 2023/7

Using "J-Coat® Quick" coated fertilizer
　　　　Localized Fertilization Technology for Paddy Rice Using Drones

Agricultural Experiment Station, Ishikawa Prefectural Agricultural and Forestry Research Center
Crop Cultivation Group
　Tomotsugu Arite, Research Specialist

1. use of drones in agriculture

　A drone is the common name for an unmanned aerial vehicle (UAV), which is defined in the Civil Aeronautics Law as "an aircraft, rotorcraft, glider, or airship that is structurally inaccessible to humans and can be flown by remote control or automatic flight control (excluding those weighing less than 100 g (the sum of the weight of the main body and the weight of the battery). (excluding those weighing less than 100 grams (the sum of the weight of the main body and the weight of the battery)). There are two types of drones: multicopter drones, which use multiple rotor blades, and airplane drones, which use fixed blades.

　Drones are characterized by their high flight stability, mobility, and expandability, including cameras and sensors. The use of drones is progressing in a variety of fields, including video production, disaster site investigation, inspection and maintenance of building structures, surveying and construction management at construction sites, and lightweight cargo transportation. Agriculture is another field where drones are expected to be utilized and are actually being used.

　Drones used in agriculture can be broadly classified into sensing drones and spraying drones (Figure 1). Sensing drones are relatively small drones equipped with cameras, and some models are equipped with multispectral cameras capable of capturing images in the near-infrared region as well as visible light, and are used for wide-area growth diagnosis and surveying of crops1).

　Spray drones are relatively large drones that can be equipped with granular or liquid spraying equipment. Compared to spraying on the ground, spraying can be done at high speeds, thus reducing work time and eliminating the need to enter the field.
Therefore, there is no risk of getting stuck in the mud. In some cases, such as in mountainous areas, where pesticides and fertilizers are applied by hand due to poor workability and uneven terrain, the use of drones for spraying can be expected to reduce labor burdens.

　In Japan, the introduction of drones for agricultural chemical application began around 2008, and their use has spread rapidly since then due to the entry of domestic manufacturers and the low cost of the aircrafts.) The Ministry of Agriculture, Forestry and Fisheries (MAFF) has set a goal of increasing the area to be sprayed by drones to 1 million hectares, and the use of drones for spraying is expected to continue to expand.

　If drones could be used not only for spraying pesticides but also for other tasks, it would lead to a reduction in per-work machinery costs, which in turn would reduce production costs and increase profits. For this reason, the Ishikawa Prefectural Agricultural and Forestry Research Center, in collaboration with OPTiM Corporation, has been studying the multifunctionality and versatility of drones, such as direct seeding of paddy rice using drones3) and local application of fertilizers and pesticides using drones only at specific locations.

　This paper introduces a drone-based localized fertilizer application technology for paddy rice, with test results using J-Coat® Quick, a coated fertilizer produced by J-Cam Agri, Inc.

Localized fertilization technology using drones

　Fertilizer is applied to rice paddies to increase the number of ears per crop and to improve the ripening rate. However, when fertilizer is applied to the entire field, there is a risk of over-abundance of nitrogen in some areas of the field, which may cause the rice to fall over if the entire field is unevenly grown. If fertilizer is applied by a drone only to areas of poor growth, it is possible to improve uneven growth while minimizing the risk of collapse.

　The flow of local fertilizer application using drones is shown in Figure 2. The work is divided into growth diagnosis using a sensing drone and fertilizer application using a spreading drone.

　First, the Normalized Difference Vegetation Index (NDVI), which is an indicator of growth, was acquired by photographing the target fields with a drone equipped with a multispectral camera around 25 to 20 days before ear emergence, which is the early stage of ear formation. NDVI is an index calculated from the reflectance in the near infrared (NIR) and visible red (RED) regions, and it has been reported4), 5) that in paddy rice, the higher the NDVI during the juvenile ear formation stage, the higher the nitrogen content and 佅 number.

　Next, the acquired NDVI images are analyzed by the field management service "Agri Field Manager" (Optim Corporation, Fig. 3) to determine where fertilizer should be applied. The need for additional fertilizer and the amount of fertilizer are comprehensively determined using the NDVI as an indicator, taking into account the variety, soil conditions, and amount of base fertilizer, etc. When a location for additional fertilizer is selected on the Agri Field Manager setting screen, a drone flight path is automatically created. The created flight path can then be input into a drone equipped with an autonomous flight function, which will fly to the selected location and apply fertilizer locally.

　Fertilizer application by a drone falls under the category of dropping objects and requires approval from the Minister of Land, Infrastructure, Transport and Tourism under the Civil Aeronautics Law without exception. For details, please refer to the website of the Ministry of Land, Infrastructure, Transport and Tourism.

3. localized fertilization of paddy rice using J-Coat® Quick

　We present the results of a local fertilization trial conducted in 2021 at our center for paddy rice. The test was conducted in a Koshihikari rice field where the amount of nitrogen in the basal fertilizer was changed to 0 kg (N0 area), 3.8 kg (N3.8 area), and 6 kg (N6 area) per 10a to artificially reproduce an uneven growth pattern. Aerial photos were taken by a sensing drone (Phantom4 Multispectral, DJI) 24 days before ear emergence, and the locations of fertilizer application were determined by considering nitrogen leaching from the base fertilizer among the locations where NDVI was less than 0.82 as shown in Figure 4. The amount of fertilizer was tentatively set at 2.5 kg of nitrogen per 10 a based on the results of a previous test.

　J-Coat® Quick, a coated fertilizer produced by Jaycam Agri (Figure 5), was used for the additional fertilization. J-Coat® Quick has a higher film disintegrating property after the leaching of fertilizer components compared to conventional LP-coated products6), 7) , and is expected to suppress the runoff of the remaining film into water after the leaching of fertilizer. In addition, compared to conventional coated urea, the leaching of the nitrogen component is faster, making this fertilizer suitable for additional fertilizer application. No particles fell through a sieve after spreading (data not shown), and the fertilizer is less likely to clog due to disintegration than urea or ammonium sulfate, making it suitable for drone application.

　Figure 6 and Table 1 show the changes in NDVI in the plots before and after fertilization. In the local fertilizer treatments, NDVI in the N0 plot increased and the coefficient of variation for the entire test plot decreased compared to the control (no fertilizer) plot, suggesting that the uneven growth of the entire plot was reduced.

　Since NDVI just before ear emergence was positively correlated with the total number of grains per square meter and yield (weight of milled brown rice) (Fig. 7), it was estimated that local fertilization reduced the area of low yield and improved the yield of the entire test area (Fig. 8). The degree of downfall was evaluated on a scale of 0 to 4, with 1.5 for the entire local fertilization area and 1.5 for the localized fertilization area.

Summary

　As described above, the drone-based localized fertilization technique reduces the risk of overthrow while also reducing the unevenness of growth.
This technology is particularly effective in fields with large differences in soil fertility, such as a combination of rice paddies. Compared to full fertilizer application
The use of fertilizers is also reduced, which leads to lower costs. Technically speaking, the use of insecticides, fungicides, herbicides, and other
This technology can be applied to any local application and is expected to lead to a reduction in the amount of pesticides used. However, the timing of growth diagnosis and the amount of fertilizer needed must be comprehensively determined based on the variety, soil conditions, amount of basal fertilizer, transplanting time, etc., and since there are inter-annual differences, further studies are needed.

　In recent years, drone models that support variable fertilizer application have appeared, and the use of drones for sensing to diagnose growth and drones for spraying to apply fertilizer is expected to continue to grow in popularity. In line with this, the use of J-Coat® Quick is expected to increase.

References

(1) Inoue, Y., Yokoyama, M. 2017. crop and farmland diagnostic information measurement by drone remote sensing and
　　Its application to smart agriculture.
　　-235.
(2) Technology Extension Division, Agriculture and Forestry Bureau, Ministry of Agriculture, Forestry and Fisheries, 2022.
3) Uno, F. 2022. direct seeding of paddy rice using drone. Journal of Paddy Direct Sowing Association, 45, p. 24-28.
4) Wakiyama, Y. 2005. relationship between vegetation index and rice paddy number.
　p.61-67.
5) Tsukaguchi, T., Kobayashi, H., Fujihara, Y., Chono, S. 2022.Estimation of spikelet number
　　per area by UAV-acquired vegetation index in rice(Oryza sativa L.).Plant Production
　　Science, 25, p. 20-29.
(6) Matsunaga, Makoto and Kotaro Shiratori 2019.Practicality of J-Coat, a paddy rice one-shot fertilizer coated with a new type of film.
　A Review of. Agriculture and Science, 707, p. 8-12.
Effects of full basal application of coated fertilizer "J-Coat" on rice plants and its film collapsibility.
　Agriculture and Science, 732, p. 1-4.

<Production Area Report

Fuji Izu Agricultural Cooperative, Nirayama Agricultural Economy Center
Introduction of the Ecolong fertilization system for large tomatoes and strawberries in

Shizuoka Fuji-Izu Agricultural Cooperative
Nirayama Agricultural Economy Center Hiroshi Koshika

　JA Fuji Izu was established in April 2022 by eight agricultural cooperatives in eastern Shizuoka Prefecture (Nansun, Fuji, Fujinomiya, Gotemba, Mishima Kannami, and Izu).
Various horticultural crops are grown in Izu-no-kuni City, which is under the jurisdiction of JA.
The prefecture is one of the leading producers of mini-tomatoes and strawberries in the prefecture. Among these, mini-tomatoes and strawberries are among the most prominent in the prefecture, and mini-tomatoes are grown in winter and spring.
The prefecture ranks first in the amount of cargo shipped and second in the amount of strawberries shipped. The cultivation system of tomatoes and strawberries
and the fertilizer "Ecolong" used.

What is "ecolong"?

This is a granular coated fertilizer that adjusts fertilizer leaching to the growth of the crop. The ECOLONG coating
is both photodegradable and microbially degradable.
　Fertilizer leaching characteristics are largely unaffected by soil pH and soil moisture.
　Contains nitrate-form nitrogen, which is effective for general field crops. It has a long-lasting fertilizing effect, so it can be grown using only basal fertilizer.
The localized application of fertilizers increases the utilization of fertilizers and allows for reduced fertilizer use. Local application of fertilizers also increases the effectiveness of fertilizer use and reduces the amount of fertilizer used.
　The elution type is either a linear type, in which elution begins immediately after fertilizer application, or a sigmoid type, in which the effect comes out slowly.
type, and the number of days in which 80% of nitrogen is leached in soil at 25°C is used in the name. Nitrogen, phosphate, potassium and trace
Different elements, elution days, and elution types allow you to select a brand that matches many applications in field crops.

Tomato Production System in Izunokuni City

　Tomatoes in Izunokuni City are planted from August to October, and harvesting begins in October and reaches its peak in March.
The season ends in early February. The main varieties grown are large tomatoes (Momotaro Hope) (CF House Momotaro), mini-tomatoes
The variety is also known as "Summer Senkatsu" (TY Senkatsu). It has excellent disease resistance, and is a good choice for
Stable production is possible up to the board.
　The Ecolong, introduced here, plays a role in maintaining yields until the end of the cultivation period.
The Super Ecolong 413 (180 type) is widely used in the pipelines. Super Ecolong 413 (180 type) is widely used mainly in the pipe line.

Cultivation system (large tomatoes)

　For tomatoes, base fertilizer is applied to the entire surface in July and August, and additional fertilizer is applied in the aisles during the sixth stage of flowering and in February.
The program will be held a total of three times.
　Super Ecolong 413-180 is recommended for large tomatoes in the Izu-no-kuni region. The reason is that in the early stage
Too much nitrogen will inhibit calcium absorption and translocation, which can lead to the formation of butt rot. Nitrogen
The key is to apply a moderate amount of fertilizer in the early growth period until fruit set, and then apply a moderate amount of fertilizer thereafter. As a fertilizer standard, 6 bags of Super Ecolong 413-180 per 10a should be applied in the aisles to maintain the fertilizer effect until the end of the harvest period, resulting in a stable yield.

Strawberry Cultivation System in Izunokuni City

　In strawberry cultivation, parental seedlings of the next year's crop are distributed in November and the parental plants are planted. The offspring plants are detached from the parent plants in July and August, and the main field is planted in June and July.
Planting in the field is done around October. Harvesting begins as early as November, reaches its peak around March, and finishes in June.
The project will be completed. There are three varieties: Benihoppe, Kirapika, and Shohime. All varieties have large grapes with a good balance of sweetness and acidity.
It will be a very popular variety with good balance.

　For strawberry fertilization, use different amounts of ECOLONG depending on the time of seedling growth. In the parental stage, use Ecolong 413
The nitrate nitrogen in the petiole was checked and fertilizer was applied as needed to prevent runner development and seedling growth.
This will enhance the quality of the seedlings. If the seedling growth period is prolonged, apply Ecolong Total 391-40 or 70 at the timing calculated backward from the scheduled planting date, so as not to run out of fertilizer at the time of flower bud differentiation. When planting in the field, apply Super ECOLONG 413-140 or 180 as basal fertilizer in soil cultivation. Application at the time of planting will prevent fertilizer run-out in early spring and promote stable growth. If fertilizer takes effect in early fall, it will affect axillary flower cluster differentiation and early rooting.

　The nitrogen leaching rate of Ecolong depends on soil temperature. The higher the soil temperature, the more nitrogen is leached out, resulting in a shorter fertilizer effect period. Conversely, the lower the soil temperature, the less leaching occurs, and the longer the fertilizing effect lasts.
Therefore, the key to stable production is to pay close attention to fertilizer management and to keep fertilizer supplies flowing.

　Therefore, in Izu-no-kuni District, we recommend "Ecolong," which works slowly and for a long time and can also save labor.

No Soil - No Soil on the Primitive Earth
　　　-This is how soil came to be on earth.

Former Technical Advisor, Hokkaido Branch, Jcam Agri Co.
Teruo Matsunaka

　All 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.
　In 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.

1. the earth before the appearance of soil

　Now, we have soil under our feet. However, those who live in urban areas with asphalt pavement may have forgotten that soil even exists. Yet, when we go out to the suburbs and look at the farmlands and fields, we see the soil. That is our daily life. It is thought that a material similar to the soil we know today (early soil) appeared on the earth about 600 million years ago. And our image of soil appeared about 300 million years ago. The birth of soil on the earth was accompanied by the following dramas (Fig. 1).

　4.6 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°C. 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°C, 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.

　At 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.

　Life 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.

2. birth of life and formation of the ozone layer

　As time progressed to 2 billion years ago, bacteria that acquired the ability to photosynthesize appeared among life in seawater. These were cyanobacteria (cyanobacteria, once classified as plants but now treated as bacteria). Cyanobacteria react with inorganic substances (minerals) in seawater and calcium carbonate to produce a rock-like substance called stromatolite, which accumulates in layers. The cyanobacteria themselves survived on the surface of the stromatolite and continued to release oxygen through photosynthesis. As a result, the atmosphere gradually began to contain oxygen. About 600 million years ago, when the atmospheric oxygen concentration increased to 2%, an ozone layer began to form (Figure 1).

　The 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.

3. birth of soil

　The lichens attached themselves to terrestrial rocks and transformed them. At the same time, when the lichens themselves died, their remains not only became organic matter that provided nutrients for the next generation, but also mixed with the altered rocks, beginning the formation of early soil on the earth. This was about 600 million years ago. This process was repeated to slowly create soil. Thus, it is thought that soil was formed on the earth about 300 million years ago. This is evidenced by the fact that huge forests of ferns, such as sealing trees and reed trees, as well as amphibians and insects appeared on the land at that time. They provide the fossil fuels of today (Figure 1).

　It 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.

4. the earth's "skin" supports terrestrial life

　The 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.

　The earth is a sphere with a radius of approximately 6,400 km (Figure 2). The center of this sphere is the core, the mantle is outside the core, and the crust is outside the mantle. The land surface accounts for only about 30% of the Earth's surface area. The continental crust is the part of the land surface that is covered with a thickness of 30 to 40 km. Soil is only a few centimeters to at most a few meters thick on the surface of the continental crust, or 18 cm on average for the entire globe (Yang, 1994). This thickness is only 1/10 millionth of the radius of the earth. The average human skin is 2 mm, or 1/1000th of the thickness of a 2-meter tall person. In other words, on a global scale, the soil is only a thin layer of skin, even thinner than the skin of a person. If the earth is represented as shown in Figure 2, the thickness of 18 cm is so thin that even the thickness of the perimeter line of the circle shown in the figure is too thick to even be illustrated.

　Plants 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.