Slow-release nitrogen fertilizer granule and preparation method thereof

Abstract

The invention provides a slow-release nitrogen fertilizer granule and a preparation method thereof. The slow-release nitrogen fertilizer granule comprises a nitrogen fertilizer granule layer, a slow-release layer and a coating layer which are arranged from inside to outside, wherein the weight ratio of the components in the slow-release layer, namely the ratio of a nitrogen fertilizer to a cross-linking agent to a film-forming agent to a proportion regulator is 1:0.5-5:0.2-2:20-100, and the coating layer is a polyurethane coating. According to the slow-release nitrogen fertilizer granule and the preparation method thereof, two protective layers can be formed on the outer layer of a nitrogen fertilizer core, one is the slow-release layer, the other is the coating layer, the slow-release layer can help the nitrogen fertilizer to form the granule with the smooth surface and has the slow release effect, the proportion of the nitrogen fertilizer granule can further be changed, the coating layer can help to realize the long-acting release of the nitrogen fertilizer, and the utilization rate of the fertilizer is improved.

Description

technical field [0001] The invention relates to the technical field of agricultural fertilizers, in particular to a slow-release nitrogen fertilizer granule and a preparation method thereof. Background technique [0002] Slow-release fertilizers are also known as slow-release fertilizers or controlled-release fertilizers. The nutrient-containing compounds in the fertilizer are released slowly in the soil or the nutrient release rate can be controlled to a certain extent for the continuous absorption and utilization of crops. [0003] Nitrogen fertilizer is the type of fertilizer with the largest production and usage of chemical fertilizers in the world. Appropriate amount of nitrogen fertilizer plays an important role in increasing crop yield and improving the quality of agricultural products, but the validity period of nitrogen fertilizer is short. 55 days, the validity period of phosphate fertilizer is more than 100 days, and the validity period of potassium fertilizer is...

AI Technical Summary

Problems solved by technology

[0004] At present, the method of producing slow-release nitrogen fertilizer mostly uses nitrogen fertilizer as the core, and coats the coating layer on the periphery of the core. The material of the coating layer is mainly polyurethane coating material. As far as the current production process is concerned, polyurethane coating The membrane has high requirements on the core, and the surface needs to be smooth to better form the coating. The current coating material is generally paraffin, but paraffin is not easy to degrade in the soil, which will have a negative impact on the soil

In addition, the density of nitrogen fertilizer is low, for example, urea is 1.335g / cm³, while the density of soil is mostly between 1.4 and 1.6 g / cm³, and the nitrogen fertilizer is wrapped with a polyurethane layer. Polyurethane is a foaming material with a low density. Nitrogen fertilizer After the polyurethane layer is wrapped, it will float on the water surface. When these fertilizers are applied, the nitrogen fertilizer cannot absorb water because the polyurethane layer is wrapped, and then the nitrogen fertilizer slow-release fertilizer will float on the soil surface, which is not conducive to the absorption of nutrients by crops. Fertilizers are easily washed away by rainwater