Research On Dynamic And Run-Off Loss Characteristics Of Nitrogen And Phosphorus In Surface Water Of Paddy Field

With the development of rural and agricultural mechanization and modernization of, it accelerates usage amount of chemical fertilizers, which seriously causes eutrophication problems in most rural areas in the south, mainly showing in the contents of high levels of nitrogen and phosphorus in water. Extensive research shows that the loss of nitrogen and phosphorus in farmland is one of important causes for eutrophication in water in south area, and the loss of nitrogen and phosphorus in paddy field with surface runoff of takes up considerable proportion.The paper studies on dynamic change of the total of nitrogen and phosphorus in field surface water by potted test and simulation test under different fertilize types, levels, measures and different temperature, preliminary getting dynamic change law of total content of nitrogen and phosphorus in surface water of field under different processing measures, and doing simulation model; analyzing relation features of rainfall and paddy field runoff and the loss of runoff nitrogen and phosphorus by simulated rainfall, analyzing run-off loss regularity of nitrogen and phosphorus for different fertilization of paddy under different rainfall intensities, mantle, measures and, to look for ideas and ways of run-off loss of controlling nitrogen and phosphorus. The main conclusions of the study are as follows:1. The influence on the concentrations of nitrogen and phosphorus in field water under different fertilization conditionsUnder different treatment of nitrogen and phosphorus, the concentrations of TN, TP, AN and NN in field water have been falling according to time goes, dropping to the lowest level after7-9day’s fertilization, and the changes of the concentrations the total of nitrogen and phosphorus in field water is not notable within9-12. The contents of the total of nitrogen and phosphorus are declining under different temperature, within3days, the order of the contents of nitrogen and phosphorus is different under different temperature treatments, and in4days, it is not different. Different fertilization methods have a greater impact on the content of nitrogen and phosphorus in field water. With the deepening of fertilization, the content of nitrogen and phosphorus in field water gradually reduces. The downward trend can be fitted with the first reaction equation (y=Co*ekx), finding that fitting results of other fertilizer level can reach significant levels except that CK cannot be fitted with this equation, and most of the treatment has reached very significant levels.2. The impacts of simulated rainfall on the content of nitrogen and phosphorus after rainfall in field water and the content of runoff nitrogen and phosphorus in different approachDifferent approaches have different impacts on the content of nitrogen and phosphorus in field water and the content of runoff nitrogen and phosphorus under simulated rainfall conditions. The level of fertilizer and the concentration of nitrogen and phosphorus in field water are positively correlated. With the increasing of nitrogen or phosphorus content, runoff nitrogen and content of phosphorus, and the content of runoff nitrogen and phosphorus after rainfall, both are increasing. Different coverage and fertilizer way have an great effect on the content of nitrogen and phosphorus after rainfall in field water and the content of runoff nitrogen and phosphorus, Along with the increasing of coverage, the content of nitrogen and phosphorus after rainfall in field water and the content of runoff nitrogen and phosphorus are gradually decreasing. According to the deepening of fertilization depth, different rainfall intensity has great influence on the content of nitrogen and phosphorus after rainfall in field water and the content of runoff nitrogen and phosphorus. Along with the increasing of rainfall intensity, the content of nitrogen and phosphorus after rainfall in field water and the content of runoff nitrogen and phosphorus are also increasing, and the bigger the rainfall intensity, the greater the amount of runoff nitrogen and phosphorus. When the rainfall intensity reaches150mm/h, the content of runoff nitrogen and phosphorus is more than the content of nitrogen and phosphorus after rainfall in field water.