Research On Nitrogen, Phosphorus Loss Characteristics Under Different Fertilization And Water Management

Under the condition of natural rainfall, based on the test method of field arunoff plots,by early rice and late rice in 2009, the paper studied the relationship between six different treatments ( No fertilization+conventional irrigation , conventional fertilization+ conventional irrigation , optimized fertilization+ conventional irrigation,increasing nitrogen fertilization+ conventional irrigation,increasing phosphorus fertilization+ conventional irrigation ,optimized fertilization+ water-saving irrigation ) and rice yield , nitrogen phosphorus accumulation,nitrogen phosphorus utilization,surface runoff loss,underground leakage. The main conclusions of the paper are as follows.(1) The quantity of N fertilizer and P fertilizer is the main reason that affected the content of N and P in rice surface, with prolonged fertilization, the content of different nitrogen and phosphorus tended to decrease, optimization fertilization can decrease the content of nitrogen and phosphorus, but water-saving irrigation has no significant effect.(2)The amount of surface runoff losses of nitrogen affected mainly by the amount of nitrogen, and phosphorus runoff loss is mainly affected by the amount of fertilizer use and runoff impact. Early rice nitrogen runoff loss was significantly higher than the amount of the loss of late rice nitrogen runoff rice, early rice of which the amount of nitrogen loss is nitrate nitrogen in the main, while the amount of late rice to ammonium nitrogen loss dominated. Optimization of nitrogen fertilizer can reduce early rice surface runoff loss 10.33 g～15.00g/666.7m2, reduce the amount of late rice surface runoff phosphorus loss 0.90 g～0.99g/666.7m2(3) Underground seepage water total nitrogen and total phosphorus is closely related to the amount of nitrogen, phosphate fertilizer and application time, leakage of water in which ammonium, nitrate and surface water are ammonium, nitrate showed a significant correlation, early rice leakage in the water of nitrogen and phosphorus levels were higher than late rice, so in the early fertilization period and late rice is possible to produce underground leaching of the primary node.(4) Fertilization can promote the improvement of paddy rice production, early rice higher than late rice, including early rice increased by 47.6%～63.6%, and increase of 31.0% rice 44.6%, while late rice for N, P utilization rate is significantly higher than early rice. Compared with conventional fertilization, respectively rice optimize fertilizer N, P utilization 3.1 and 1.8 percentage points, to improve late rice N, P utilization 1.0 and 1.3 percentage points, N, P utilization will be reduced if increasing N or P fertilizer , water-saving irrigation to improve the N, P utilization was no significant difference, but consider the conservation of resources can be used as important promotional model for future...