The Research Of Non-point Source Pollution Of Paddy By Different Combination Models Of Water And Fertilizers

China has the widest rice-planting areas and the highest rice consuming around theworld at present. Nowadays, as the high level of water consumption and chemical fertilizerusage in rice culture, a mass of nitrogen and phosphorus washed away which causesaggregated non-point source pollution in agriculture. Based on this issue, finding asustainable rice-producing model in high productivity, saving water and controllingpollution is especially important. In this study, we focused on the integrative affection ofwater and fertilizer usage on rice. With the systematic observation on rice productivity,water and fertilizer usage, nitrogen and phosphorus loss based on different methods ofirrigation, different levels and times of fertilization, we found that the model W1N2F2wasthe most economical one to select. The specific condition of W1N2F2is listed as follow:(1) The rice yield from intermittent irrigation was higher than from full water irrigation;when increasing the nitrogen level in a proper range, the yield increased relatively,however, this relation faded away as more nitrogen was used (higher than12kg（Nitrogen）/acre); in addition, more times of nitrogen usage also can increase productivity.(2) The result of water uptake and drainage of early and late season rice under differentwater and fertilization condition showed, intermittent irrigation was more suitable forwater usage by reduced water consuming, irrigation and drainage; as more nitrogen used,more water was needed and less was drained away; the water usage efficiency of threetimes of fertilization was higher than two times, drainage water was less.(3) With the observation of nitrogen usage efficiency of early and late season rice underdifferent water and fertilization usage, the uptake ratio of nitrogen was not increased alongwith more nitrogen fertilized but related to the times of fertilization, the uptake ratio washighest in N2F2and lowest in N2F1, more times of fertilization increased nitrogen uptake.(4) The nitrogen loss along with drainage consisted major of Ammonia and minor ofNitrate. The loss of nitrogen and phosphorus of early and late season rice was less withintermittent irrigation than full water irrigation; among the different levels of nitrogenusage, the nitrogen loss of early and late season rice was extremely significant andincreased as more nitrogen fertilized, however, the loss of phosphorus was decreased underthis condition. The loss of nitrogen and phosphorus was lower with three times fertilizationthan two times.