Effects Of Slow-controlled Release Fertilizer And Reducing Nitrogen Application On Loss And Utilization Of Nitrogen And Upland Crop Yield

Field experiments with controlled release urea and common urea fertilizer were adopted to study the effects of slow-controlled release fertilizer and application of reducing nitrogen on ammonia volatilization, runoff loss, N2O emissions, nitrogenous fertilizer use efficiency and upland crop yield in the condition of summer maize and pakchoi rotation. The main results were as follows:1. The ammonia volatilization loss, loss rate and duration of ammonia volatilization flux of controlled release urea were significantly lower than common urea treatment, and they decreased as the reducing of nitrogen fertilizer application. Compared with common urea treatment, constant controlled release urea treatment could reduce the ammonia volatilization losses by50.27%. Controlled release urea reduction by10%to30%could reduce the ammonia volatilization losses from52.25%to52.25%.2. Controlled release urea could obviously reduce the surface runoff loss of grain nitrogen, water soluble total nitrogen, ammonium nitrogen and nitrate nitrogen in summer maize and pakchoi rotation land, and they decreased as the increase of controlled release urea nitrogen reduction. Compared with common urea, the constant controlled release urea treatment could reduce the nitrogen runoff losses20.80%. Controlled release urea reduction10%to30%could reduce nitrogen losses from26.89%to31.37%.3. Nitrogen could obviously promote the N2O emissions. Compared with common urea, the application of controlled-release urea could significantly slow down and reduce the accumulation of N2O emissions in the summer maize and pakchoi rotation land, and the accumulation of N2O emissions reduced as the decrease of nitrogen content. Compared with common urea treatment, the accumulation of N2O emissions in each controlled release urea treatments were reduced by14.05%,29.64%,14.05%and29.64%respectively.4. Controlled release urea could significantly reduce nitrogen nutrient leaching loss in summer maize and pakchoi rotation land. Compared with common urea, nitrate nitrogen content in soil profile of the four controlled release urea treatments were reduced by18.43%-49.53%, ammonium nitrogen contents were reduced by11.59%-72.02%and total nitrogen contents were reduced by0.27%-6.77%.5. Compared with common urea, constant controlled release urea treatment promoted nitrogen use efficiency of pakchoi increased by1.91%, maize grain and pakchoi yield increased by1.13%and10.51%respectively. Nitrogen use efficiency of controlled release urea nitrogen reduction10%to30%increased by2.09%-5.36%. Maize grain and pakchoi yield were decreased slightly, but the reduction of yield was not significant.To sum up, under this experimental condition, the effects of controlled release urea fertilizer on summer maize and pakchoi were better than that of common urea. Controlled release urea nitrogen reduction10%to30%could reduce nitrogen loss in summer maize and pakchoi rotation land, and would not lead to crop failures.