Controlled-release fertilizer for mechanical transplanting of rice as well as preparation method and application of controlled-release fertilizer

Abstract

The invention relates to the technical field of fertilizer production, in particular to a controlled-release fertilizer for mechanical transplanting of rice as well as a preparation method and application of the controlled-release fertilizer. The controlled-release fertilizer for mechanical transplanting of rice is prepared from the following raw materials in percentage by mass: 17%-21% of urea, 9%-13% of 40-day anti-floating controlled-release urea, 9%-13% of 80-day anti-floating controlled-release urea, 8%-12% of diammonium hydrogen phosphate, 18%-22% of potassium chloride and 27%-31% of calcium magnesium phosphate fertilizer. The formula of the controlled-release fertilizer provided by the invention is basically consistent with a'double-peak 'nitrogen accumulation absorption curve from the tillering stage and the ear differentiation to the heading stage of the rice, and can meet the nutrient requirements of the whole growth period of the rice, so that the yield of the rice is increased by 11-22%; the nitrogen fertilizer absorption and utilization rate is increased by 15%-16%; the net income of farmers is increased by 11%-25%, and the method has very high practical application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fertilizer production, in particular to a rice machine transplant controlled-release fertilizer and a preparation method and application thereof. BACKGROUND

[0002] As China's primary food crop, the yield of rice accounts for 30.37% of the total grain yield in 2022, which is crucial to the national food security. Reasonable fertilization is the key to improving rice yield and fertilizer utilization rate. However, current rice production relies heavily on water-soluble quick-acting single-element fertilizers, and slow-release fertilizers are underutilized, and there is excessive and unreasonable fertilization, leading to mismatch between nutrient release and rice demand, and soil acidification. Studies have shown that rice has a bimodal pattern of nitrogen demand, with the highest demand during the tillering stage and the stage from panicle differentiation to heading. With traditional fertilization, in addition to basal fertilization, multiple topdressing is required, which not only results in low nitrogen utilization rate, resource waste, and environmental pollution, but also may cause seedling burn. In addition, with the transfer of labor force, multiple fertilization increases labor costs, restricting the precision fertilization of the rice industry. Therefore, it is necessary to develop a low-cost and high-nitrogen utilization rate controlled-release fertilizer. SUMMARY

[0003] To solve the above technical problems, the present application provides a rice machine transplant controlled-release fertilizer, which can increase the yield of rice by 11% to 22%, improve the nitrogen absorption and utilization rate by 15% to 16%, and increase the net income of farmers by 11% to 25%, having high practical application value.

[0004] The present application provides a rice machine transplant controlled-release fertilizer, which is composed of the following raw materials in mass percentage: urea 17% to 21%, 40-day anti-floating controlled-release urea 9% to 13%, 80-day anti-floating controlled-release urea 9% to 13%, diammonium phosphate 8% to 12%, potassium chloride 18% to 22%, and calcium-magnesium phosphate fertilizer 27% to 31%.

[0005] Further, the rice machine transplant controlled-release fertilizer is composed of the following raw materials in mass percentage: urea 19%, 40-day anti-floating controlled-release urea 11%, 80-day anti-floating controlled-release urea 11%, diammonium phosphate 10%, potassium chloride 20%, and calcium-magnesium phosphate fertilizer 29%.

[0006] Further, the mass percentage of nitrogen in the 40-day anti-floating controlled-release urea is 43% to 47%, and the 40-day anti-floating controlled-release urea is a controlled-release fertilizer with a nutrient supply period or fertilizer efficiency period of 40 days.

[0007] Further, the mass percentage of nitrogen in the 80-day anti-floating controlled-release urea is 42% to 46%, and the 80-day anti-floating controlled-release urea is a controlled-release fertilizer with a nutrient supply period or fertilizer efficiency period of 80 days.

[0008] Furthermore, the mass percentage of nitrogen in the diammonium hydrogen phosphate is 12%~18%, and the mass percentage of phosphorus is 43%~47%.

[0009] This invention provides a method for preparing the controlled-release fertilizer for machine-transplanted rice, comprising the following steps: Weigh out the following ingredients by mass fraction: urea, 40-day anti-floating controlled-release urea, 80-day anti-floating controlled-release urea, diammonium hydrogen phosphate, potassium chloride, and calcium magnesium phosphate fertilizer. Mix them together to obtain the final product.

[0010] This invention provides an application of the controlled-release fertilizer for rice transplanting in rice cultivation.

[0011] Furthermore, when planting rice, fertilization is carried out simultaneously with rice transplanting, that is, the controlled-release fertilizer for rice transplanting is applied along with the seedlings to a depth of 3cm to 7cm from the root zone and 3cm to 7cm from the soil surface.

[0012] Furthermore, based on the amount of pure nitrogen applied, the application rate of the controlled-release fertilizer for machine-transplanted rice is 150 kg / hm². 2 ~180 kg / hm 2 .

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The controlled-release fertilizer formula for rice provided by this invention combines urea, 40-day anti-floating controlled-release urea, 80-day anti-floating controlled-release urea, diammonium hydrogen phosphate, potassium chloride, and calcium magnesium phosphate to obtain a one-time controlled-release fertilizer for rice, achieving the purpose of fertilization in one application without harming the seedlings.

[0014] The controlled-release fertilizer for rice transplanting provided by this invention requires only one application to meet the dynamic nitrogen nutrient needs of rice throughout its entire growth period, eliminating the need for subsequent topdressing. Furthermore, this controlled-release fertilizer uses only two controlled-release ingredients, significantly reducing fertilizer costs and saving manpower and resources. Compared to traditional multiple fertilizations, applying this controlled-release fertilizer can increase rice yield by 11%–22%; improve nitrogen fertilizer absorption and utilization rate by 15%–16%; reduce fertilization costs by 70 yuan / mu; and increase income by 11%–25%.

[0015] The controlled release fertilizer formula provided by the application comprises calcium magnesium phosphate fertilizer, the fertilizer is a silicate glass body containing phosphate, and in addition to providing phosphorus, it also provides silicon, calcium, magnesium, sulfur and other trace elements, can improve the stress resistance of rice to a certain extent, promote the photosynthesis of rice, make the growth of rice healthier, and improve the yield of rice. The SiO2, CaO and MgO nutrients in the calcium magnesium phosphate fertilizer are more effective than those provided by most industrial slag, the sulfur contained in the calcium magnesium phosphate fertilizer can improve the utilization rate of nitrogen fertilizer to a certain extent, the cooperation of magnesium and nitrogen can improve the content of chlorophyll, the cooperation of silicon, magnesium, phosphorus and potassium can reduce the nitrogen content in rice, promote the growth of rice roots and stress resistance, and improve the quality of rice. The fertilizer is a water-soluble fertilizer, and the fertilizer efficiency is better than that of superphosphoric acid calcium in acid soil; meanwhile, the fertilizer is rich in alkaline nutrient elements, so that the exchangeable calcium and magnesium contents of soil are increased by 40.45 mg / kg-55.01 mg / kg and 10.18 mg / kg-21.75 mg / kg respectively; as a physiological alkaline fertilizer, the fertilizer can neutralize the acidity generated by urea and ammonium phosphate in the soil, reduce the soil acidity, and increase the soil pH by 0.11-0.30. The application provides a convenient one-time controlled release fertilizer scheme for rice, which can be popularized to medium and low yield rice, has great universality, and can be widely used in rice producing areas. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0017] Figure 1 The nitrogen release curve of the rice machine insertion controlled release fertilizer of the application and the nitrogen nutrient absorption curve of rice. DETAILED DESCRIPTION

[0018] The specific embodiments of the application will be described in detail below, but it should be understood that the protection scope of the application is not limited by the specific embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application. The experimental methods described in the embodiments of the application are conventional methods, and the materials and reagents used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0019] The controlled release fertilizer of the application is used in field test in Baisha Science and Education Base in Fuzhou City, Fujian Province, and the test variety is a local conventional variety. The local conventional split fertilization is used as a control group.

[0020] The 40-day anti-floating controlled-release urea and the 80-day anti-floating controlled-release urea are purchased from Maosheng Agricultural Technology Co., Ltd.

[0021] The mass percentage of phosphorus in the diammonium hydrogen phosphate is 45%, and the mass percentage of nitrogen is 15%.

[0022] Embodiment 1 The rice machine transplanting controlled-release fertilizer is composed of the following raw materials in mass percentage: urea 19%, 40-day anti-floating controlled-release urea 11%, 80-day anti-floating controlled-release urea 11%, diammonium hydrogen phosphate 10%, potassium chloride 20%, and calcium-magnesium phosphate fertilizer 29%.

[0023] The mass percentage of phosphorus in the diammonium hydrogen phosphate is 45%, and the mass percentage of nitrogen is 15%.

[0024] The mass percentage of nitrogen in the urea is 46.3%.

[0025] The mass percentage of nitrogen in the 40-day anti-floating controlled-release urea is 45%, which is a controlled-release fertilizer with a nutrient supply period or fertilizer effect period of 40 days.

[0026] The mass percentage of nitrogen in the 80-day anti-floating controlled-release urea is 44%, which is a controlled-release fertilizer with a nutrient supply period or fertilizer effect period of 80 days.

[0027] The sum of the mass percentages of nitrogen and phosphorus in the diammonium hydrogen phosphate is 60%, wherein the mass percentage of nitrogen is 15% and the mass percentage of phosphorus is 45%.

[0028] The mass percentage of potassium in the potassium chloride is 60%. The mass percentage of chlorine in the potassium chloride accounts for 48% of the total amount of chlorine in the rice machine transplanting controlled-release fertilizer.

[0029] The mass percentage of phosphorus in the calcium-magnesium phosphate fertilizer is 12%, the mass percentage of sulfur is 8%, the mass percentage of calcium is 45%, and the mass percentage of magnesium is 12%, and the rest is silicate and other inert carriers.

[0030] The nutrient ratio of the rice controlled-release fertilizer in the preferred technical solution is 20:8:12 (referring to the mass ratio of N:P2O5:K2O), and the fertilizer application amount is 10 kg / acre in terms of pure nitrogen amount. Before fertilization, according to the total nitrogen application amount, the urea, 40-day anti-floating controlled-release urea, 80-day anti-floating controlled-release urea, diammonium hydrogen phosphate, potassium chloride, and calcium-magnesium phosphate fertilizer are taken according to the formula ratio, and each component is fully stirred and mixed to obtain the rice machine transplanting controlled-release fertilizer.

[0031] The fertilization method is: 3 days before transplanting, rotary tillage is carried out to level the field, and the field tillage depth is 13 cm; 1 day before transplanting, fine soil is raked to make the field flat, without stubble and water is poured to soak the field; at the time of transplanting, fertilization is carried out synchronously with rice transplanting, and the rice machine transplanting controlled release fertilizer is applied to the side 5 cm of the seedling rhizosphere and the soil depth 5 cm.

[0032] Example 2 A rice machine transplanting controlled release fertilizer is composed of the following raw materials in percentage by mass: urea 20%, 40-day anti-floating controlled release urea 12%, 80-day anti-floating controlled release urea 12%, diammonium hydrogen phosphate 8%, potassium chloride 20%, calcium magnesium phosphate fertilizer 28%, and the total is 100%.

[0033] The mass percentage of nitrogen in urea is 46.3%.

[0034] The mass percentage of nitrogen in 40-day anti-floating controlled release urea is 45%, and the nutrient supply period or fertilizer effect period of the controlled release fertilizer is 40 days.

[0035] The mass percentage of nitrogen in 80-day anti-floating controlled release urea is 44%, and the nutrient supply period or fertilizer effect period of the controlled release fertilizer is 80 days.

[0036] The sum of the mass percentages of nitrogen and phosphorus in diammonium hydrogen phosphate is 60%, wherein the mass percentage of nitrogen is 15% and the mass percentage of phosphorus is 45%.

[0037] The mass percentage of potassium in potassium chloride is 60%. The mass percentage of chlorine in potassium chloride accounts for 48% of the total amount of chlorine in the rice machine transplanting controlled release fertilizer.

[0038] The mass percentage of phosphorus in calcium magnesium phosphate fertilizer is 12%, the mass percentage of sulfur is 8%, the mass percentage of calcium is 45%, the mass percentage of magnesium is 12%, and the rest is silicate and other inert carriers.

[0039] The nutrient ratio of the rice controlled release fertilizer in the preferred technical solution is 21:7:12 (referring to the mass ratio of N:P2O5:K2O), and the total nitrogen application amount is 10 kg / acre in terms of pure nitrogen amount. Before fertilization, according to the total nitrogen application amount, urea, 40-day anti-floating controlled release urea, 80-day anti-floating controlled release urea, diammonium hydrogen phosphate, potassium chloride, and calcium magnesium phosphate fertilizer are taken according to the formula ratio, and each component is fully stirred and mixed to obtain the product.

[0040] The fertilization method is: 3 days before transplanting, rotary tillage is carried out to level the field, and the field tillage depth is 13 cm; 1 day before transplanting, fine soil is raked to make the field flat, without stubble and water is poured to soak the field; at the time of transplanting, fertilization is carried out synchronously with rice transplanting, and the rice machine transplanting controlled release fertilizer is applied to the side 5 cm of the seedling rhizosphere and the soil depth 5 cm.

[0041] Example 3 The rice machine transplanting controlled release fertilizer is composed of the following raw materials in percentage by mass: urea 18%, 40-day anti-floating controlled release urea 10%, 80-day anti-floating controlled release urea 10%, di-ammonium hydrogen phosphate 12%, potassium chloride 20%, calcium magnesium phosphate fertilizer 30%, and the total is 100%.

[0042] The mass percentage of nitrogen in the urea is 46.3%.

[0043] The mass percentage of nitrogen in the 40-day anti-floating controlled release urea is 45%, and the nutrient supply period or fertilizer efficiency period of the controlled release fertilizer is 40 days.

[0044] The mass percentage of nitrogen in the 80-day anti-floating controlled release urea is 44%, and the nutrient supply period or fertilizer efficiency period of the controlled release fertilizer is 80 days.

[0045] The sum of the mass percentages of nitrogen and phosphorus in the di-ammonium hydrogen phosphate is 60%, wherein the mass percentage of nitrogen is 15% and the mass percentage of phosphorus is 45%.

[0046] The mass percentage of potassium in the potassium chloride is 60%. The mass percentage of chlorine in the potassium chloride accounts for 48% of the total amount of chlorine in the rice machine transplanting controlled release fertilizer.

[0047] The mass percentage of phosphorus in the calcium magnesium phosphate fertilizer is 12%, the mass percentage of sulfur is 8%, the mass percentage of calcium is 45%, the mass percentage of magnesium is 12%, and the rest is silicate and other inert carriers.

[0048] The nutrient ratio of the rice controlled release fertilizer in the preferred technical solution is 19:9:12 (referring to the mass ratio of N:P2O5:K2O), and the fertilization amount is 10 kg / acre in terms of the nitrogen application amount. Before fertilization, according to the total nitrogen application amount, the urea, 40-day anti-floating controlled release urea, 80-day anti-floating controlled release urea, di-ammonium hydrogen phosphate, potassium chloride and calcium magnesium phosphate fertilizer are taken according to the formula ratio, and each component is fully stirred and mixed to obtain the rice machine transplanting controlled release fertilizer.

[0049] The fertilization method is as follows: rotary tillage is performed 3 days before transplanting, and the field is plowed to a depth of 13 cm; the fine soil is raked to make the field flat, free of stubble and waterlogged 1 day before transplanting; the rice machine transplanting controlled release fertilizer is applied to the rhizosphere of the seedlings at a depth of 5 cm, and the soil is applied to a depth of 5 cm.

[0050] Comparative Example 1: The farmer's conventional fertilization method is to apply base fertilizer: tillering fertilizer: flowering promoting fertilizer: flowering maintaining fertilizer = 3:3:2:2 in four times. The special compound fertilizer for rice (nutrient content N:P205:K20 = 17:17:17) is used as base fertilizer. The field is rotary plowed 3 days before transplanting, with a plowing depth of 13 cm. The fine soil is raked 1 day before transplanting to make the field flat and free of stubble and water is used to soak the field. The special compound fertilizer for rice 17.65 kg is applied before transplanting, and then the seedlings are transplanted manually. Urea (nitrogen mass percentage 46%) is used as tillering fertilizer, flowering promoting fertilizer and flowering maintaining fertilizer after transplanting. The total nitrogen application amount is 10 kg / acre. The comparative examples are all applied manually and applied on the soil surface.

[0051] Among them: tillering fertilizer: 6.52 kg of urea is applied 9 days after transplanting; flowering promoting fertilizer: 4.35 kg of urea is applied 43 days after transplanting; flowering maintaining fertilizer: 4.35 kg of urea is applied 52 days after transplanting.

[0052] Comparative Example 2: Set up no fertilizer group The field is rotary plowed 3 days before transplanting, with a plowing depth of 13 cm. The fine soil is raked 1 day before transplanting to make the field flat and free of stubble and water is used to soak the field. Then the seedlings are transplanted manually. No fertilizer is applied before and after rice planting.

[0053] The rice one-time controlled release fertilizer formula is researched by Examples 1-3 and Comparative Examples 1-2. The cumulative release rate of nitrogen in the controlled release fertilizer and the cumulative release rate of nitrogen in rice are determined by Example 1. The related test methods and test results are shown as follows:

[0054] I. Determination of each index 1. Yield determination Select an area of 15 m*15 m for rice harvesting, threshing, cleaning and weighing, and then convert the actual yield according to the standard moisture content of 13.5%.

[0055] 1. Biomass determination After the rice matures, take 3 holes as a sample, 3 times repeated, separate the ear and stem and leaf, kill green at 105℃ for 30 min, then dry at 70℃ to constant weight, weigh, get the total dry weight of ear and stem.

[0056] 2. Plant nitrogen content determination Grind the dried samples of each treatment, and determine the ear nitrogen content and stem and leaf nitrogen content by Kjeldahl method.

[0057] 4. Nitrogen accumulation (kg / hm 2 ) = sum of corresponding nitrogen content of each part of biomass.

[0058] 5. Nitrogen utilization rate (%) = (nitrogen accumulation amount of nitrogen application area - nitrogen accumulation amount of blank area) / nitrogen application amount x 100% 6. Determination of soil pH, available phosphorus, exchangeable calcium and exchangeable magnesium After the rice is harvested, 20 cm soil is selected away from the fertilization point, 5 points are randomly selected according to the "S" type, and the soil is mixed and taken as a representative of the plot. The sample is labeled and taken back to the laboratory, impurities are removed, and the sample is naturally air-dried on kraft paper, ground and passed through a 2 mm (10 mesh) sieve. The soil pH is determined by the potential method (soil to water ratio of 1:2.5), the soil available phosphorus is determined by the molybdenum blue colorimetric method, and the exchangeable calcium and exchangeable magnesium are determined by atomic absorption spectrometry.

[0059] The experimental results are shown in Tables 1 and 2: Table 1 Effect of controlled-release fertilizer on soil pH, soil available phosphorus and exchangeable calcium and magnesium Table 2 Effect of controlled-release fertilizer on rice yield, nitrogen utilization rate and increase in farmers' income Note: "-" in the table means no such item.

[0060] As can be seen from Table 1, compared with the conventional fertilization method of farmers (Comparative Example 1), the soil pH is increased by 0.11-0.30, the soil available phosphorus content is increased by 5.32 mg / kg-10.52 mg / kg, and the exchangeable calcium and exchangeable magnesium are increased by 40.45 mg / kg-55.01 mg / kg and 10.18 mg / kg-21.75 mg / kg, respectively, indicating that the controlled-release fertilizer of the present application has the effects of adjusting soil acidity, increasing soil available phosphorus and exchangeable calcium and magnesium content, and improving soil conditions.

[0061] As can be seen from Table 2, compared with the conventional fertilization method of farmers (Comparative Example 1), the rice yield of the examples is increased by 11%-22%, the nitrogen absorption utilization rate is increased by 15%-16%, the conventional fertilization of farmers is performed 4 times, the total labor cost per mu is 4 workers, and the cost of fertilization is calculated at 30 yuan per mu per worker, the application reduces the fertilization cost by 70 yuan per mu (the machine application cost of the controlled-release fertilizer of the present application is 50 yuan per time), and the net income of farmers is increased by 11%-25% in combination with the fertilizer cost and the labor cost of fertilization.

[0062] Therefore, it is proved that the controlled-release fertilizer of the present application can adjust soil acidity, increase soil available phosphorus and exchangeable calcium and magnesium, improve soil conditions, reduce fertilizer waste, increase rice yield and increase farmers' income.

[0063] II. Determination of nitrogen accumulation release rate of controlled-release fertilizer and nitrogen accumulation release rate of rice

[0064] 1. Test method The cumulative release rate of controlled-release fertilizer nitrogen was determined in the laboratory by the following method: 10 ± 0.01 g of the fertilizer sample was accurately weighed into a nylon mesh bag with a pore size of 1 mm, the bag opening was tied tightly, and the bag was placed in a 250 mL triangular flask, 200 ml of water was added, and after sealing, the flask was incubated in a 25°C incubator. The sampling time was 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 days, and the nitrogen content in the solution was determined by the Kjeldahl method.

[0065] The cumulative absorption rate of rice nitrogen was determined by field sampling, and the determination method was as follows: sampling was performed at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 days after transplanting, and after drying and crushing, the nitrogen content in the aboveground part of the plant was determined by the Kjeldahl method.

[0066] 2. Test results The cumulative release curve of controlled-release fertilizer nitrogen and the cumulative absorption curve of rice nitrogen are shown in Figure 1 The cumulative release curve of controlled-release fertilizer nitrogen showed that after the fertilizer was applied, the nitrogen release rate was significantly improved at 0d~40d and 70d~90d, which was basically consistent with the "double-peak" nitrogen cumulative absorption curve of rice during the tillering period and the period from panicle differentiation to heading, and no additional fertilizer was needed during the late growth period of rice. Compared with the conventional fertilization treatment, the one-time application of controlled-release fertilizer could meet the nutrient demand of rice during the entire growth period.

[0067] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they understand the basic inventive concept.

[0068] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A rice machine transplanting controlled release fertilizer, characterized by, The 40-day anti-floating controlled-release urea is a controlled-release fertilizer with a nutrient supply period or fertilizer efficiency period of 40 days, and the mass percentage of nitrogen thereof is 43-47%. The 80-day anti-floating controlled-release urea is a controlled-release fertilizer with a nutrient supply period or fertilizer efficiency period of 80 days, and the mass percentage of nitrogen thereof is 42-46%.

2. The rice machine transplant controlled release fertilizer according to claim 1, wherein, The mass percentage of nitrogen in the diammonium hydrogen phosphate is 12-18%, and the mass percentage of phosphorus is 43-47%.

3. The rice machine transplant controlled-release fertilizer according to claim 1 or 2, characterized by, The method comprises the following steps:

4. The rice machine transplant controlled-release fertilizer according to claim 1, characterized by, The urea, the 40-day anti-floating controlled-release urea, the 80-day anti-floating controlled-release urea, the diammonium hydrogen phosphate, the potassium chloride and the calcium-magnesium phosphate are weighed according to the mass fraction and mixed to obtain the product.

5. The rice machine-planting controlled-release fertilizer according to claim 1, characterized in that, 7. Application of the rice machine transplanting controlled-release fertilizer according to any one of claims 1-5 to planting of rice.

6. A method of preparing the rice machine transplant controlled release fertilizer according to claim 1, characterized in that, When the rice is planted, the rice machine transplanting controlled-release fertilizer is applied to the rice seedling rhizosphere side 3-7 cm and the soil depth 3-7 cm. ​ ​ 8. Use according to claim 7, characterized in that, ​ 9. Use according to claim 7, characterized in that, The application amount of the rice machine transplanting controlled release fertilizer is 150 kg / hm 2 180 kg / hm 2 .

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