Study On The Loads And Control Measures Of Agricultural Non-Point Source Pollution In Qing Tong Xia Irrigation District

Recently, along with the highlighted water environmental issues and relatively improving control standards of the point source pollution (PSP), Non-point source pollution (NSP), agricultural non-point source pollution (AGNSP) problem especially caused by heavy use chemical fertilizers and pesticides has aroused great concern and attention. This paper, taking the Qing Tong Xia Irrigation District at the Yellow River upstream as an example, adopting research means which the monitor experiment in typical area and the model simulation combined, taking the typical AGNSP experimental area monitor test material as the foundation, has analyzed the migration characteristic of typical pollutants in the water conveyance system, the field system and the drainage system of irrigation district. According to the production and the migration characteristic of AGNSP, the AGNSP model was divided into "Sources" and "Sinks" module, integrating two modules, the complete AGNSP load model was constructed. Applying this model, the Qing Tong Xia Irrigation District AGNSP loads were calculated in 2008 May-September. At the same time, combined with the specific circumstances of Qing Tong Xia Irrigation District, the AGNSP control measures were put forward.The main content and innovative achievements of this paper can be concluded as follows:(1) The Qing Tong Xia Irrigation District AGNSP experimental area was established by selecting typical irrigation and drainage channels and typical field, experiment was conducted in 2007 and 2008 respectively, total experimentation lasted 180 days,186 water samples and 960 pollutant indexes, more than 600 date of irrigation amount and drainage amount in field were obtained. Based on the experiment date, the migration characteristic of typical AGNSP pollutants in the water conveyance system, the field system and the drainage system were analyzed.(2) Based on the AGNSP characteristic which the unit load characteristic is obvious, the migration way is complex, the AGNSP model was divided into "Sources" module and "Sinks" module. Thereinto, "Sources" Module is further divided into farmland irrigation drainage sub-module and contaminants concentrations in farmland drainage estimating sub-module; "Sinks" module also includes farmland drainage sub module and pollutants migration transform sub module. Integrating two modules, the complete AGNSP load model was constructed.(3) Appling the AGNSP model constructed, considering crop planted structure in the Qing Tong Xia Irrigation District in 2008, the Agricultural non-point source field pollution load and the output coefficient of pollutants in Qing Tong Xia Irrigation District were calculated respectively. Based on this, the major AGNSP output load of Qing Tong Xia Irrigation District in 2008 May-September were calculated. there are:salinity 470099t, total phosphorus 98.17t, total nitrogen 3593t, nitrate nitrogen 2122t, ammonia nitrogen 426t;(4) According the different migration characteristics of "Sources" and "Sinks" links, quantitative analysis by model, different control measures were put forward in "Sources" and "Sinks" links. "Sources" link control measures include saving irrigation, scientific fertilization technique and controlled drainage in paddy field etc. "Sinks" links control measures include ecological engineering technology, such as ditch wetlands and riparian forest buffers etc, and resource utilization of the drainage.