Agricultural Non-point Source Pollution Research

Along gradual controlling the point source pollution, the non-point source pollution has become a majority of water contamination. Among non-point source pollutions, the agricultural non-point source pollution is the biggest one. The agricultural non-point source pollution is defined to be the runoff transports of constituents include the nutrients, the agricultural chemicals and soon nitrogen and phosphorus element and all that are organic or the inorganic pollution matter from diffuse sources on the land to streams. Through the farmland surface runoff, the agricultural drainage and the underground leakage, cause the water environmental pollution.The Dasha River is the main river in Pulandian. The area is 964 square kilometers, and the length is 96.5 kilometers. Average slope is 1.34‰, diameter current capacity 260 million cubic meters, and the depth is 269.7mm.In the basin plants crops is mainly type. The agricultural non- point source pollution already became one of main reasons which the Dasha River quality worsened. Therefore, conducting the agricultural non- point source pollution research to this basin is valuable.This paper summarizes the state of the agricultural non-point source pollution research at home and abroad, research the Pulandian the Dasha river basin agricultural non- point source pollution situation. Mainly studies are about the total nitrogen (TN) and the total phosphorus (TP) pollution situation.This research selects 5 sampling spots, from upstream to downriver respectively after Yuan Tai, Ba Jiazi, Hou Xianshi, Haipi Bridge, Hou Dayuan. The dry season and the abundant water time two examinations.The TN of Yuan Tai achieves II water-quality standard, The TN of Ba Jiazi, Hou Xianshi,Haipi Bridge achieve III water-quality standard; The TN of Hou Dayuan achieves IV water-quality standard. The main reason is the agricultural non- point source pollution of the Dasha River basin and the industry point source pollution. According to the Dalian agriculture non- point source pollution background research, the agricultural non- point source pollution the main pollution reason which increases the TN of the Dasha River basin.The TN increases from the upriver to the downriver. Ba Jiazi cross sections TN density increases the scope to be comparatively greatly possible with this cross section water volume to be less; the rivers reduce from only the ability concern. The latter yard cross section TN density is highest, surpasses the surface water III water-quality standard.The dry season TN value slightly is higher than the abundant water time, mainly is because dry season river water current capacity small, speed of flow is low, the water body quite is only weak from the ability. In spring the apply fertilizer after rain causes the nitrogen run off along with the surface, also creates the TN higher.