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| DOI：10.13522/j.cnki.ggps.20190268 |
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| Study on Simulation of Agricultural Non-point Source Pollution in Shaying River under Water-fertilizer Coupling Model |
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MA Jianqin, GUO Wei, LIU Lei
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1.North China University of Water Resources and Electric Power, Zhengzhou 450045, China; 2. Henan Branch of Construction and Administration Bureau of South-to-North Water Diversion Middle Route Project, Zhengzhou 450000, China
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| Abstract: |
| 【Background】Water is an indispensable and precious natural resource for human and other organisms to survive, as well as for socio-economic development and agricultural production. Water resources shortage has become the focus of people’s attention. With the continuous growth of China’s population and the rapid advancement of industry, agriculture and urbanization, environmental pollution has become increasingly serious, the ecological environment around rural areas has been destroyed, especially for water pollution. The problem of water pollution is usually classified into point source pollution and non-point source pollution according to its source. When people worked for effective management and control of point source pollution, while water quality has not been much improved, they gradually realize the non-point source pollution is the main factor of water pollution of the environment. Control of watershed non-point source pollutant load on the output water quality plays a very important role in environmental protection. In recent years, the application amount of fertilizer driven by agricultural production increase is increasing, and the water body in China is generally polluted by non-point agricultural sources. The eutrophication of water body and the continuous decline of river water quality, and the water environment pollution are increasingly serious, which has become one of the hot issues concerned by the academia and production departments. In response to national policies, it is urgent to analyze the impact of reducing the amount of irrigation and fertilizer applied to agricultural crops on the output load of non-point source pollutants in different regions.【Objective】 By studying the effects of different combinations of water and fertilizer on the output of nitrogen and phosphorus pollution load in farmland, the optimal coupling scheme of water and fertilizer will be determined.【Method】At present, because of the lack of a pollution monitoring system, the uncertainty of the pollutant emission points make it difficult to simulate agricultural non-point source pollution. This study used the verified SWAT model to simulate the spatial and temporal distribution characteristics of TN and TP loads of farmland non-point source pollution in Shaying River basin from 2008 to 2015, and the variation of pollutant output loads under different irrigation and fertilizer rates was comprehensively considered.【Result】By comparing the changes of nitrogen and phosphorus load under 16 scenarios, it was concluded that the reduction rate of pollution load was positively correlated with the reduction of fertilizer application amount, and the pollution load reduction effect was the best under S4 mode. The reduction rate of pollution load is negatively correlated with the reduction amount of irrigation water, and the reduction effect of pollution load is the best under S8 mode. When both irrigation and fertilization were coupled, the trend of total nitrogen reduction slowed down with the decrease of irrigation fertilization, and the trend of total phosphorus reduction varied under different scenarios.【Conclusion】When the amount of fertilizer and irrigation water are reduced by 30% or 40% respectively, the effect of agricultural pollution reduction is the best. |
| Key words: SWAT model; the Shaying River; agricultural non-point source pollution; simulation; water and fertilizer coupling |
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