Effects Of CRNFs Application On Moving And Transforming Characteristics Of Nutrients In Paddy Soil And Rice Growth

In order to illustrate mechanism of moving and transformation characteristics of nitrogen in controlled-release nitrogenous fertilizers (CRNFs) and its effects on rice, simulative submerged soil experiment, rice pot experiment and rice field plot experiment were conducted in this study. Compared with common urea. CRNFs showed a great ad vantage on rice growth. The findings provided a theoretic basis for the processing techniques and fertilizer availability research of CRNFs. The main results and conclusions were as follows:1. The nutrient release curves of CRNFs in water showed a shape of parabola with a peak of release rate in the course of nutrient release. At the beginning, nutrient release rate increased slowly, reached maximum in 50 days, and decreased slowly after peak release.2. The results of simulative submerged soil experiment showed that CRNFs were able to keep the stabilization of soil pH and EC. Other nutrients, such as available N, available P, available K, and NF4+-N were abundant for CRNFs treatment.3. The content of available N> available P^ available KxNH4+-NxNO3"-N and organic matter, in 0-20, 20-40,> 40-60cm soil layers at two rice growth stages were greater with CRNFs treatment than these with common ureau treatment.4. The contents and availability of nutrients in soil surface 晈ith CRNFs treatments were a!1 higher than these with common nitrogenous fertilizers treatments. Application of CRNFs could maintain a better soil fertility condition in surface layer as compared to the common urea treatments.5. During the period of rice growth of rice, chlorophylK length of leaves ^ width of leaves and the area of leave index with CRNFs treatment were all greater than these with common nitrogenous fertilizers treatment, Application of CRNFs could improve the growth condition of rice, promote the individual development and construction of rice and increased photosynthesis efficiency..6. The contents of N,, P, K in the plants with CRNFs treatment were singnificantly higher than these with common nitrogenous fertilizers treatments. Application of CRNFs could improve nitrogen use efficiency.7. Although the total biomass of rice plants with CRNFs was not significantly increased, the yield of rice seeds was singnificantly greater than that of common urea treatments by 17.7-34.6% as compared with common ureau treatments. At the same N application rate was still higher than that of common ureau. The results proved that CRNFs singnificantly increased the N use efficiency.