Coated slow-release compound fertilizer and preparation method thereof

Abstract

The invention discloses a coated slow-release compound fertilizer and a preparation method thereof. The compound fertilizer comprises a urea nuclear as well as a wrapping layer and a hydrophobic layer which coat the urea nuclear from inside to outside, wherein the wrapping layer is formed by performing high-heat mixed melting on powdery nitrogen, powdery phosphorus and powdery potassium, and the powdery nitrogen in the wrapping layer accounts for 15%-25% of the total nitrogen in the coated slow-release compound fertilizer; the hydrophobic layer is made of resin. The coated slow-release compound fertilizer disclosed by the invention can meet nutritional requirements of crops in different stages, is low in cost and has an environment-friendly effect.

Description

technical field [0001] The invention relates to an agricultural chemical fertilizer, in particular to a coated slow-release compound fertilizer. Background technique [0002] The current slow / controlled release fertilizers are mainly used in cash crops and golf courses. The main constraints that limit their wide application in agriculture are: 1. The cost of slow / controlled release fertilizers is high, mainly due to the high price of slow release materials and the preparation process. Complicated, small-scale coating equipment and high cost make the price of the final product too high. The current price of slow-release fertilizer is 2400-2600 yuan / ton, which is difficult for farmers to accept. 2. The current coating material is basically resin, which is difficult to degrade when it enters the soil. The degradation cycle is 30-50 years, and the continuous application will pollute the soil. 3. Most of the current slow / controlled release fertilizers are single substance type, ...

AI Technical Summary

Problems solved by technology

[0002] The current slow / controlled release fertilizers are mainly used in cash crops and golf courses. The main constraints that limit their wide application in agriculture are: 1. The cost of slow / controlled release fertilizers is high, mainly due to the high price of slow release materials and the preparation process. Complex, small-scale coating equipment and high cost make the price of the final product too high. The current price of slow-release fertilizer is 2400-2600 yuan / ton, which is difficult for farmers to accept

2. The current coating material is basically resin, which is difficult to degrade when it enters the soil. The degradation cycle is 30-50 years, and the continuous application will pollute the soil.

3. Most of the current slow / controlled release fertilizers are simple substance type, which are mainly coated with nitrogen, while ignoring the slow release of phosphorus and potassium

Long-term excessive and blind fertilization has caused serious pollution, leading to serious eutrophication of surface water, high nitrate in groundwater and a series of ecological and environmental problems. Excessive nitrogen fertilizers lead to ammonia volatilization, and the resulting greenhouse gases such as NH3, N2O, N2 have expanded the global greenhouse effect

Excessive fertilization for a certain period of time leads to excessive nutrient stress and poisoning, resulting in reduced seed germination rate and reduced quality of agricultural products

4. It is difficult to achieve compatibility between price and output

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