Prevention Of Agricultural Non-point Source Pollution Of Guanting Water Protection Land

At present, non-point source pollution which is caused by more and more extensive use of chemical fertilizer and the misuse of fertilizer is more and more manifest in our agricultural production. The utilization efficiency of chemical fertilizer is low in china, only 30%-35%nitrogenous fertilizer of crop is effective used, one part of the rest nitrogenous fertilizer lost by volatilize or the way of nitric, the other part of the rest detained in soil, or lost with surface runoff in rainfall and irrigation, or run into under-water with leaching water, that caused great influence on water environment. Research on the prevention techniques of agricultural non-point pollution in water protection area is of great importance. The text provided scientific evidence for quantitative assessment the potential hazard of nitrogenous fertilizer on the groundwater, proposing measures to reduce the lost of nitrate nitrogen leaching and laying down a environmental friendly system of fertilization. The main conclusion follows:1.There are many decision factor affected farmers' fertilizer. The main factors are farmers age, and cultural level, agricultural product price, rural organization and agricultural policies. In the investigation, the phenomenon of appreciating of nitrogen fertilizer, contempt of potash fertilizer is widespread under the precondition of pursuit the maximum profit.2.The result which was investigated soil at Xiaofengying Yanqing county at March 2007 showed that the content of organic substances, total nitrogen, available phosphorus, available phosphorus at vegetable plot are more than corn plot and the mixed area of corn and vegetable plot.3.The result which was investigated the content of nitrate in groundwater from 2006 to 2008 showed that about 15% groundwater which is III type of water is unfit for direct drink. The content of nitrate in groundwater of vegetable plot is on the top in this three years, which distributed at 3.24-4.92 mg/L, the follow is fruit tree plot, which distributed at 2.03-2.25 mg/L, corn plot is the lowest, which distributed at 1.12-1.21 mg/L.4.Test results of using vegetable plot nitrogen control techniques in the area indicated that there was no significant difference between nitrogen of reducing 10% to 30% and normal treatment on economic yield, nitrogen content and soil nitrate content are positive correlation, the results indicated that nitrogen control techniques had a certain role on reducing nitrogen leaching down and reducing the content of soil nitrate, and it had better environmental benefits.5.In the test of reducing soil nitrate leaching of vegetable plot using nitrogen control techniques, comparing normal treatment, resin coating can significantly improve economic yield of cabbage; the three kinds of controlled release fertilizer can be keep nitrate in the main root in the cabbage in a certain period, the effects of resin coating is relatively stable at rosette stage, heading stage and harvesting time, sulfur coated and DCD added nitrogen are effective in the early period, leaching is strengthened in the latter period.6.In the test of reducing soil nitrate leaching of vegetable plot using nitrogen control techniques, resin coating and sulfur coated had a significant role on economic yield of spring corn, and both reduced the content of soil nitrate significantly.