Study On The Effects Of No-Tillage And Grass Hedges Practice On The Removing Of Typical Agricultural Non-Point Source Pollutants

Chemical fertilizer and herbicide are widely used in agricultural production. These chemicalsubstances can result in serious water pollution. In order to evaluate the decreasing effects of twopractices (no-tillage, grass hedges, no-tillage and grass hedges) on the loss of nitrogen,phosphorus and atrazine with runoff. This experiment was conducted in Beijing slopingcroplands, with different slope gradients and under simulated rainfall and natural rainfallcondition. It is hoped that the results will be helpful for preventing agricultural non-point sourcepollution in China. The results mainly achieved are as follows: the no-tillage practice cansignificantly prevent agricultural non-point source pollution. The grass hedges can improve thesoil structure, reduce the bulk density and soil hardness, increase soil permeability and preventagricultural non-point source pollution. And the integration of no-tillage and grass hedges isproved to be very efficient in preventing agricultural non-point source pollution. The runoff, totalnitrogen and total phosphorus under nature rainfall in the plots with the integration of no-tillageand grass hedges is69%,62%,68%,88%, respectively. By simulated rainfall experiments, thedecreases are77%,76%,77%,82%, respectively. Under the5%~20%slope, the results showthat no-tillage and grass hedges significantly reduce agricultural non-point source pollution.There is a negative correlation between slope gradient and no-tillage practice effectiveness. Inaddition, the effectiveness of no-tillage and grass hedges practice in preventing runoff, nitrogen,phosphorus and atrazine loss gradually decreased with the increasing slope gradient. Regressionanalysis shows that there is a positive correlation between runoff and agricultural non-pointsource pollutants.