Study On The Preparation And Application Of Controlled-slow Release Nitrogen Fertilizer

With the increasing concern about the environment and health,it is the important task of agricultural fertilizer innovation to reduce the amount of fertilizer,improve the utilization rate of nitrogen fertilizer and reduce the impact on the human health and environment on the basis of ensuring grain yield.In this paper we mainly studies two kinds of nitrogen fertilizer,aiming at increasing the utilization rate of nitrogen fertilizer,reducing environmental pollution and improving the quality of agricultural products.In chapter 1,we mainly studied the granulation of ammonium chloride fertilizer in a laboratory scale based by the pan granulator Significant improvement of granulation efficiency of ammonium chloride was achieved by using polyaluminium chloride as solid binder and urea as granulation additive.Highly charged cations by polyaluminium chloride hydrolysis could reduce the electrostatic repulsion of ammonium chloride,leading to efficient particle agglomeration.Analyzing the surface structure and characteristics of the polyaluminium chloride and ammonium chloride granules revealed that their interactions lead to the formation of aggregate nucleus.Furthermore,polyaluminium chloride contained a larger number of active groups,which can form particle–polymer–particle complex and facilitate the growth of particle.Meanwhile,urea and ammonium chloride could react with each other to form stable inclusion complex and also had pronounced effect on the increase of granulation rate for ammonium chloride.In chapter 2,a kind of coated controlled release nitrogen fertilizer was prepared by using cheap and environmentally friendly humic acid as the coating material and urea as the kernel of fertilizer.The suitable conditions for the coating were determined by experiments.The process was convenient,simple,rich in raw materials and low cost.In the coating,through the complex chemical reaction and physical adsorption of urea and humic acid,the coating thickness was uniform,smooth and compact and the hardness of the particles increased.In addition,humic acid could not only ameliorate the soil and stimulate the growth of plant roots,but also can be a good urease inhibitor,which can inhibit the hydrolysis of urea before the crop growth cycle,increase urea nitrogen utilization and reduce nitrogen consumption.In chapter 3,different types of nitrogen fertilizers were applied to the lawns,and the lawns were randomly selected.The effects of different controlled-slow release fertilizers and fast release fertilizer on turfgrass growth and turf quality were studied,in the case of applying the equal nitrogen content.The results showed that urea and ammonium chloride could rapidly improve the color of the lawn.But controlled-slow release nitrogen fertilizer could extend the release period of nitrogen,so that the improvement of lawn color was more lasting,and the lawn grew fast and evenly.It is proved that the two nitrogen fertilizers studied in this paper have a certain sustained release effect,which is beneficial to keep the nitrogen content of turfgrass tissue relatively stable,reduce the cost of lawn conservation and management,and is more conducive to protecting the environment.