The Research On The Relation Between Agricultural Structure And Recession Water Quality

Ningxia Yellow River is one of the oldest and the biggest irrigation region in China.Therefor With the development of agricultural investment , the non-point pollution caused by agricultural production and rural life is more and more serious, Therefore, in order to define the pollution index, strengthen irrigation load management , the relationship of agricultural structure with water quality,and agricultural non-point pollution load and the relationship between the maintenance irrigation ecological environment, This research based on the spot investigation, the field detection, typical watershed test, and model estimation methods to evaluate the sources of agricultural non-point pollution, the present situation and the relationship of agricultural retreat water and structure. Research results show that agricultural irrigation area-source pollution sources include livestock breeding, planting, people life sewage and so on, the livestock breeding is the greatest of the nonpoint source pollution load , of 43% of the total load, the relationship of nitrogen phosphorus loss change and Livestock breeding is the highest degree, the correlation coefficient is 0.75. Meanwhile, with the change of season, the nitrogen and phosphorus of refund wate are also produces change of 6 ~ 8 months. According to Serial reactor simulation, Yellow River irrigation region water quality of nonpoint source pollution load is corresponding with Yellow River water quality, the absolute error is around 0.4.,Points out that agricultural non-point pollution irrigation agriculture back into the concentration of water produces far more than three water quality standards., Beyond the self-purification capability of the Yellow River,it can be to cause water pollution. This paper main conclusions are as follows:1. The planting, livestock and poultry breeding is the main pollution sources of Ningxia Yellow River irrigation region. The planting the output of the TN, TP 7294200kg, 233400kg respectively; Raising livestock pollution load of TN, TP output load 8119600 kg, 878200kg respectively; Rural residents living pollution load the TN, TP 4538200kg, 737400kg respectively in 2008 year.2. From pollution load time-space distribution characteristic analysis, the irrigation TN and TP load Showed a rising trend since 1990year, In the irrigation area around the city in the pollution load distribution,the regional was differences in 2008, it counld be sorted such as: LiTong region﹥PingLuo county﹥QingTongXia county﹥yinchuan city >ZhongNing county﹥YongNing county﹥LingWu city﹥HeLan county﹥shizuishan city.3. according to analysis of the typical regional agricultural pollution and agricultural irrigation water, livestock breeding is the most concentration to the water quality of nitrogen and phosphorus among planting, raising livestock and breeding.In addition, the seasonal changes in pollutant concentration monitoring look, June to August refund water TN and agricultural concentration of TP highest4 Use S - P model and serial reactor correction model of nonpoint source pollution load irrigation basin with the Yellow River water quality relationship between agricultural irrigation tentative simulation, all nonpoint source pollutants into the theory of refund water, cause for concentration of 6.8 mg/l TN, TP 0.6 mg/l. The two pollutants into the Yellow River water back after starting pollution concentration into 2.3 mg/l, 0.16 mg/l, beyond self-purification capability of the Yellow River. Serial reactor simulation of HuangHeZhong TN, TP concentration changes and actual monitoring concentration changes are in absolute error analysis by around 40%.