Environmental Impact Assessment And Control Strategy Of Pollution Caused By Agricultural Non-Point Source

At present, although point source has been controlled and treated very well, non-pointsource has become the key pollution source of the surface waters continuously. Non-pointsource is the main cause that results in the surface water pollution, in which the non-pointpollution caused by agricultural activities is the possible maximum pollution contribution tothe surface water pollution. The problems for surface water environment pollution caused byagricultural non-point source are very serious in our country at present. The major pollutantsare ammonia nitrogen and total phosphorus derived from agricultural non-point source.Agricultural non-point source pollution has the features of such randomicity, uncertainty ofthe pollutants and draining pathways, and space-time variation of the polluting loads. It isdifficult to estimate the discharges of the pollutants produced by agricultural non-point sourceaccurately. Pollutant output-efficient model as well as others can be employed to estimate thedischarges of the pollutants produced by agricultural non-point source. Ratio of isoparametricpollution discharge parameter was presented to assess the environmental impact ofagricultural non-point source on the surface waters. The strategy of the green carryingcapacity of croplands for animal bred in a region was presented to implement the scientificmanagement for the excrements of the animal husbandary. The case study showed that theratio of the pollution contribution of the ammonia nitrogen to the surface waters was 82.7percent in 2001 in Jilin province, which was the biggest pollution source, whereas that of theammonia nitrogen from the urban domestic sewage was 14.5 percent and ammonia nitrogenfrom industries 2.8 percent. The ratio of pollution contribution caused by the ammonianitrogen from animal husbandary was 56.3 percent, which was the biggest pollution source ofthe agricultural non-point source pollution, the bigger was that from the agriculturalcultivation with the ratio of 27.0 percent, and the least was 16.7 percent from farmers. Theagricultural ecological project and saving-water irrigation project should be constructed,scientific fertilization should be implemented, arable land saline management should bestrengthened, public sense for the agricultural environment protection should be heightened,and planning for agricultural environment protection should be drawn out, in order to alleviateand control the surface water pollution caused by agricultural non-point source.