Application Of Three Mathematical Methods On Soil And Water Environmental Pollution Evaluation In Vegetable Land

The study that chooses soil and water environment in vegetable land as the research objects, analyses and tests the content of the soil,surface water and groundwater samples in Qingdao in DaGu river basin .The soil sample contains As, Cd, Cr, Cu, Hg, Ni, Pb, Zn, COD, total phosphorus and total nitrogen. The surface water sample contains the COD, total phosphorus and total nitrogen. The groundwater water sample contains total hardness, potassium permanganate index, ammonia nitrogen, nitrate nitrogen, fluoride, sulfate, iron, manganese, and chlorine. The principal component analysis , grey correlation analysis and fuzzy comprehensive evaluation are used to evaluate and analyse non-point source pollution of study area.The principal component analysis and the grey relational analysis are used to analyse non-point source pollution in DaGu river basin, which basically get the same conclusions. This study shows that the principal component analysis reveals the extent of soil and water pollution and the inner relationships and differences between them. The method identifies the main components of the pollutants which are Cd, As, Zn, Ni which basically gets the same conclusions with the reality. It shows the reliability of the principal component analysis method. The grey correlation analysis can reflect that environmental quality of the sample points representing area has the greatest impact on total nitrogen in soil and total phosphorus in surface water, the second are As, Cd, Zn and COD in soil. Analysis results indicate that the input of heavy metal Cd, As, Zn has important influence on environmental quality of the local soil. Analysis shows that the environmental quality of soil and water which are located in Jimo's sample points is good, and located in pingdu's sample points is poor.The fuzzy comprehensive evaluation method is used to evaluation the water quality based on total hardness, potassium permanganate index, ammonia nitrogen, nitrate nitrogen, fluoride, sulfate, iron, manganese, and chlorine in Qingdao in 2008 . Analysis results show that evaluation parameters of sample points which are located in Jimo and Jiaozhou are in level II range quality and located in Pingdu are in levelⅤrange quality based on the water quality assessment standard. The reason for the difference is agricultural non-point source pollution, and this study also puts forward some constructive suggestions for agricultural non-point source pollution in DaGu river basin.