Szu-Ying Tung1, Noriaki Harada1, Yuichi Sekiguti2, and Hiroshi Aoki2
1JCAM AGRI TAIWAN Co., LTD.,
2JCAM AGRI Co., LTD., Tokyo, Japan
The fertilizer industry faces a continuing challenge to improve its products to increase the fertilizer use efficiency and to minimize any possible adverse environmental impact. For this purpose, studies on the development of coated fertilizers have been done all over the world. In this paper, we are introducing our coated urea “MEISTER” as the sophisticated fertilizer, explaining the features and applications in actual fields. “MEISTER” is the coated urea with a mixture of polyolefin and silicate mineral. “MEISTER” has two releasing types. One is the linear type. Another is the sigmoidal type. Release of nitrogen from “MEISTER” mainly depends on temperature which allows the precise prediction of nutrient release. Application experiments for rice, Chinese cabbage and long onion are introduced in this paper. Every experiment shows single basal application is possible by using “MEISTER” with keeping yield and high nitrogen recovery. Coated fertilizers show accurately controlled release of nutrients. The use of coated fertilizers brings a) efficient use of fertilizer resources. b) Reduction of environmental load by fertilizer. c) Labor saving. Thus applying coated fertilizers is definitely smart fertilization technology in agriculture. Coated fertilizers seem to closely meet the requirements of an ideal fertilizer. The problem is its high price comparing to the normal rapid soluble fertilizer. Though total application cost of coated fertilizers is often cheaper than the cost of rapid soluble fertilizers, unit price of coated fertilizer is expensive on the surface. This sometime disturbs the spread of coated fertilizers. So, we have been trying to make an effort to reduce production cost and application enlargement trials of coated fertilizers for becoming more widespread. Through those studies and development, we believe coated fertilizers will contribute more to agriculture.
Keywords: Coated fertilizer, release control, rice, Chinese cabbage, long onion, co-situs, nitrogen use efficiency, MEISTER, NUTRICOTE
Fertilizer materials have contributed to food production for many years. At the same time, the fertilizer industry faces a continuing challenge to improve its products to increase the fertilizer use efficiency, particularly nitrogenous fertilizers, and to minimize any possible adverse environmental impact. (Trenkel, 2010). For this purpose, studies on the development of coated fertilizers have been done all over the world. According to the coating materials, the fertilizers are divided into three groups: sulfur-coated, thermosetting resign coated, and thermoplastic resign coated fertilizers. Table 1 shows the invention and development of coated fertilizer until 1989. (Fujita et al. 1989).
Table 1. Development of coated fertilizer
At present (2017), main producers and its plants are located in North America, West Europe, Israel, China and Japan. Total capacities of coated fertilizer are estimated more than 3,000,000t a year. Especially, Chinese companies rapidly increase their capacity.
In Japan, studies on the development of coated fertilizers were started almost 50 years ago and a variety of coated fertilizers have been manufactured. The production quantity was around 60,000 tons in 1995 and reached more over 100,000 tons in 2014 (Fig.1, Anonymous, 2017). Especially, coated fertilizer is very popular and is used more by 35% of the paddy fields with diffusion of fertilizer drill rice transplanters (Fig. 2, Anonymous, 2009).
Fig. 1. Production of Coated Fertilizer in Japan
Fig. 2. Diffusion ratio of fertilizer drill rice transplanter and coated fertilizer in rice cultivation in Japan
In this paper, we are introducing our coated urea “MEISTER” as the sophisticated fertilizer, and explaining the features and its contribution to the development of agriculture like its applications in actual fields.
FEATURES OF COATED UREA “MEISTER”
In the late 1976, we started manufacturing polyolefin-coated compound fertilizers “NUTRICOTE” as the first nutrient-releasing controlled fertilizer in the world (Shoji et al., 1992). Polyolefin-coated urea “MEISTER” followed suit in 1980. We have developed and manufactured a variety of the nutrient releasing controlled fertilizers for various crops with different purposes by a full use of our coated technology.
Composition and type of “MEISTER”
The structure of “MEISTER” is presented in Photo. 1. Granular urea (2-4mm) is coated with a mixture of polyolefin and silicate mineral. (10% wt./wt. against urea) The thickness of membrane is 40-60mm. Specifically designed coating machine is used for the film coating with the highest uniformity in thickness.
There are two releasing types for “MEISTER”. One is the linear type. Nitrogen is released almost linearly from the start to dissolve 80% of urea into water. Its longevities are from 30 to 360 days at 25 degree C (Fig. 3). Total Nitrogen content is 42%. The other is the sigmoidal type. This type has a lag period of 20 to 100 days and release period of 20 to 100 days after lag period at 25o C (Fig. 3). Its total nitrogen content is 41%.
Photo. 1 Cross section of MEISTER granule
Fig. 3. Nitrogen release of MEISTER in water at 25℃
Releasing mechanism of “MEISTER”
Fig. 4 describes the segment releasing mechanism of “MEISTER”. At first, the water moisture is taken into the particle through the membrane of “MEISTER”. Next, the water taken in through membrane dissolves internal fertilizer. Then, the water pressure in the “MEISTER” particle is increased and urea solution leaks out through the membrane.
Fig. 4. Segment release Mechanizm of “MEISTER”
From the releasing mechanism, the releasing rate of “MEISTER” is influenced by temperature. The temperature affects the rate of water vapor permeability through the membrane. Another soil property such as pH, texture, soil moisture (if it is not below 30% of field capacity) and so on don’t affect the releasing so much.
After knowing the soil templature, we can simulate the releasing longevity by using the computer. We can choose the coated fertilizer type and longevity coping with plant’s nutrition demand. Fig. 5 is the example that shows the preferable “MEISTER” blend for strawberry cultivation in Kyushu Japan and its simulated release by the computer.
Fig. 5. Releasing simulation of “MEISTER” blend for strawberry in Kyusyu
Efficiency of “MEISTER” in the field
Due to the release pattern, the nitrogen release from “MEISTER” is usually synchronized with growth rate of crops. “MEISTER” has lasting nitrogen supply. So, recovery of this fertilizer by the crop is much higher than that of a rapid soluble one. Then relation between the fertilizer treatment and nitrogen use efficiency (NUE) is shown in Fig. 6 (Kaneda, 1995). The NUE of “MEISTER” is more than twice of ammonium sulfate because of its controlled releasing nature as crops demand. In particular, co-situs application proved the highest efficiency of nitrogen use over 80%, and this is a strong proof “MEISTER” is superior to existing conventional fertilizer in not only labor saving, but also economic and environmental viewpoint.
Fig. 6. Relation between applied position and Nitrogen efficiency
Features of coated urea “MEISTER”
Summarizing the features of the coated urea “MEISTER”, we can point out four advantages to compare with conventional fertilizers. These are based on high NUE of “MEISTER”.
First, it is “Easy fertilization”. NUE of “MEISTER” is very high so that farmers can reduce application times and rate by using “MEISTER”. Only one time basal application is also possible because nitrogen needed for whole growth of crops can be applied at one time without salt injury. It’s very easy for farmers.
Second is “Low production cost”. Reducing the application times and quantity saves on labor cost. Though the price of coated fertilizer is usually more expensive than conventional fertilizers, total fertilizer cost of “MEISTER” including labor coat, fertilizer application cost and so on is often lower from conventional fertilizers.
Third is “Releasing simulation”. Release of nitrogen from “MEISTER” is not affected by soil properties such as pH, texture, soil moisture (if it is not below 30% of maximum water holding capacity), oxidation-reduction potential, ionic strength of the soil solution and so on. Release is mainly dependent on temperature which allows precise prediction of nutrient release over time. After knowing the soil templature, we can simulate the releasing longevity by using the computer. We can choose the “MEISTER” type and longevity coping with plant’s nutrition demand.
At last, it is “Lower Environmental Pollution”. Increasing the recovery of nitrogen from “MEISTER” by crops means less nitrogen entering into the environment. Large uptake by crop makes leaching to underwater decrease. In addition, reducing the application quantity may decrease nitrous oxide gas emission at least equivalent value of reducing quantity.
APPLICATION OF COATED UREA “MEISTER” AND BLENDED FERTILIZER “MEISTER-MX”
“MEISTER” is the coated urea. It contains only nitrogen. So, we usually blend “MEISTER” with compound fertilizers or/and single fertilizer to apply in the actual field. Blend composition is considered in the condition of crops, temperature and cultivation field. We name blended one “MEISTER-MX”
“MEISTER” and “MEISTER-MX” are extensively applied to a variety of crops in Japan where the labor cost of farming is rapidly rising. In this section, we introduce the application experiments of rice, Chinese cabbage and long onion in Japan.
Otsuka studied the single basal application of “MEISTER” for rice in Saga prefecture, Japan. (Otsuka, 2018) In this study, three species of rice (Yumeshizuka, Hinohikari and Hiyokumochi) were evaluated at the Saga agricultural research center in 2015. Fertilizer was applied by a transplanter with side row fertilizing machine. The former cultivation of rice was the barley and its fertilizer dosage was N:P:K=120:57:86 kg/ha.
The fertilizer dosage and the growth data of each treatment are in Table. 2. Only nitrogen was applied. “MEISTER” was sigmoidal type. Depending on the species, releasing longevity was changed. “MEISTER” dosage was reduced by three steps compared to the conventional method.
Table 2. Nitrogen fertilizer treatment and growth of rice
Due to the lack of initial nitrogen from sigmoidal type of “MEISTER”, culm length and number of ears were less than conventional.
Table 3 describes the result of brawn rice yield and nitrogen recovery rate. The more the dosage of “MEISTER” was applied, the more the yield was obtained. Comparing to the conventional, more than 60% of “MEISTER” dosage led to the same or more yield. In addition, nitrogen recovery rate of “MEISTER” was more than twice of the conventional.
Table 3. Yield and nitrogen recovery rate
As the result, almost the same yields were obtained at three rice species by applying 60% of “MEISTER” nitrogen from the conventional, though culm length and number of ears were less than the conventional. Using “MEISTR” can reduce 40% fertilizer cost due to the cost calculation. (Table 4)
Table 4. Comparison of Fertilizer Cost ($/¥=110)
“MEISTER” can control its releasing precisely. Using some kind of sigmoidal types “MEISTER”, seeding can be made together with fertilization without fertilizer salt injury to the rice (Photo. 2). This type of “MEISTER” can supply all the nutrients necessary for the plant to grow during the whole growing period in nursery box application, and tillage for fertilization is unnecessary. We JCAM-AGRI name this type of coated fertilizer “NAEBAKOMAKASE”. This new farming method can save on other major field operations, thus reducing the costs, of rice farming. Now “NAEBAKOMAKASE” is estimated to use more than 23,000ha rice field especially northeastern Japan (2011).
Photo. 2. NAEBAKOMAKASE
Ikeda estimated the single basal application of “MEISTER” for Chinese cabbage in Aichi prefecture Japan to reduce the nitrogen leaching from fertilizers. (Ikeda, 1994) The study was done at the Aichi agricultural research center for two years.
The fertilizer application dosages are in Fig. 5. The basal fertilizer of conventional was normal NPK compound. The additional fertilizer was normal NK compound. Regarding to the coated urea treatment, 30% of nitrogen was applied from ammonia sulfate and DAP. Remaining 70% of nitrogen was “MEISTER”. “MEISTER” was the linear type of 40 days. Multiphosphate was used as another phosphate. Potassium sulfate and Potassium silicate were applied as potassium. In 1993, 80% nitrogen of conventional treatment was set as the dosage reduction in “MEISTER” treatment.
Table 5. Application dosage at Chinese cabbage experiment
Plants at the “MEISTER” treatment grew smoothly as same as one at the conventional both years. The weights at the “MEISTER” treatments were better than one at the conventional even the 20% nitrogen reduction in 1993. (Table 6).
Table 6. Yield of Chinese cabbage experiment
Nitrogen recovery rate was calculated and soil analysis was done in 1993 (Table 7). Nitrogen recovery rates of “MEISTER” were 60% while that of the conventional was 54%. Soil EC and nitrate nitrogen at the “MEISTER” treatments were less than those at the conventional.
Table 7. Nitrogen recovery rate and soil analysis (1993)
Murakami studied one time basal application for a long onion by using a local fertilizing machine with planting trench in Akita prefecture Japan. (Murakami, 2005)
The fertilizer application dosages are in Fig. 8. The conventional nitrogen, phosphate and potash were normal rapid soluble fertilizers. The total nitrogen at the conventional was 240kg/ha. On the other hand, there were two “MEISTER” treatments to find the suitable longevity. One was applied with the linear type of 40-day (40Nkg/ha) and the sigmoidal type of 60-day (120Nkg/ha). Another was applied with the linear type of 40- day (40Nkg/ha) and the sigmoidal type of 100-day (120Nkg/ha).
Table 8. Application dosage at long onion experiment
Table 9 describes the result of yield and nitrogen recovery rate. Applying the sigmoidal 100-day type led to be good at the N recovery but not so good at the yield comparing with the conventional. On the other hand, the sigmoidal 60-day type was better at the N recovery and yield than the conventional. This means the sigmoidal 100-day type is a little bit long longevity for growth of long onion and the sigmoidal 60-day type is suitable for the long onion in this area.
Table 9. Yield and Recovery Rate
APPLICATION IN SPACE CRAFT BY NASA
NASA has studied several coated fertilizers to find a suitable fertilizer using in space. They chose and evaluated “OSMOCOTE”, “POLYON” and “NUTRICOTE”. “NUTRICOTE” is the brand name of NPK compound coated fertilizer by JCAM-AGRI, using the same coating technology with the coated urea “MEISTER”. After the research, they concluded “NUTRICOTE” was the most effective at delivering steady-state release of nutrients in the mid-temperature (20 degree to 30 degree). (Adams et al, 2013) NASA has chosen “NUTRICOTE” as the fertilizer for their cultivation system “Veggie” in space and been applying “NUTICOTE” in the space craft.
Coated fertilizers like a “MEISTER” is kind of thermoplastic resin coated fertilizer whose release of nutrients is mainly determined by temperature. This type of coated fertilizers shows accurately controlled release of nutrient. The use of coated fertilizers brings some merits for agriculture as follows.
Coated fertilizers can supply all the nutrients in a pattern synchronizing the demand of the plants during the whole growing period. High recovery of coated fertilizer is obtained at the field. This makes the reduction of fertilizer application dosage and saves the fertilizer resources.
Normal soluble chemical fertilizers are known to be contributing to serious problems of environmental pollution such as salt accumulation, nitrate contamination of underground and surface water by leaching and run off, and increase in nitrous oxide in the air by denitrification. The controlled release of nutrients from coated fertilizers and synchronized uptake of nutrients by crops could reduce these environmental loads by fertilizer application. Coated fertilizers are definitely environmental friendly fertilizers.
Single basal application can cut the additional applications. This reduces the labor cost. Recently, a rapid decrease in agricultural population and rapid aging of farmers have continued in Japan. This trend will occur in other countries near future. Using coated fertilizers is one of the measurements to solve the labor shortage in agriculture. Actually, coated fertilizers are widely used for paddy rice, upland crops and horticultural plants in Japan.
Thus applying coated fertilizers is really a smart fertilization technology in agriculture.
Coated fertilizers seem to closely meet the requirements of an ideal fertilizer. But the problem is its high price compared to the normal fertilizers. Though coated fertilizers are popular for many crops in Japan, there is a limitation to apply coated fertilizers in the world especially in developing countries. We think one of the reasons is the high price of coated fertilizers. Though total cost of applying coated fertilizers is often cheaper than one of rapid soluble fertilizers, unit price of coated fertilizer is expensive on the surface. This sometimes disturbs the spread of coated fertilizers. So, we have been trying to make an effort to reduce production cost and application enlargement trial in many countries for becoming widespread. Through those studies and development, we believe coated fertilizers will contribute to the development of agriculture in the world.
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