Activated Lignite Coated Urea Nutrient Release Characteristics And Biological Effects

To improve the utilization rate of nitrogen fertilizer and to avoid environmental pollution is a urgent problem during nitrogen fertilization. The main nitrogen varieties-urea is used in this study and the activation lignite as package material, study on the nutrient release characteristics and crop effect of the wrapped urea. Provide a reference basis for the production applicationThis research is divided into three parts, the first part was the effect on humic acid content and its morphology characteristics of lignite of machinery and chemical activation; The second part was release features of lignite-wrapped urea under different conditions and the parcel layer structure variation; The third part was the effect on potted rapeseed of lignite parcel urea.Then make an evaluation of its effectiveness. The main results are as follows:(1) Activate the coal through machinery and chemical method and determine the content of humic acid, we found that activity humic acid content increased at the begaining and then reduced with the extension of mechanical activation time, when the grinding time is10min to achieve the highest levels, the content of free humic acid and water-soluble humic acid improved by65.3%and100.0%, respectively than that of raw materials. The lignite present uniform particles and has no granular binder particles at this time under electron microscope scanning; Under the same grinding time, when add chemical activator.free humic acid content and water-soluble humic acid content increased by8.7%～13.1%and49.9%～13.1%respectively.(2) The nutrient release rate of lignite package urea is accelerated with the increasing of initial moisture content of the soil, the surrounding temperature and the soil PH. The nutrients release rate was fast at the very begaining and then became slowly. The nutrient release the fastest in the first four days, slowly when4d to6d, after8d it release almost complete. Dissolution conditions of the parcel layer structure performed more obvious with the increasing temperature and the extension of release time.(3) The effect on rapeseed of lignite parcel urea fertilizer.In early growth stage and the medium, the dry weight and effective leaf number of rapeseed with coated urea were not as good as that with the ordinary urea; at the end of growth, compared with the common urea, the dry weight increased by19.2%, effective leaf number increased by16.3%. plant total nitrogen content increased by9.3%and chlorophyll content increased by18.7%, the accumulated nitrogen uptake increased by29.4%.