| Xinxiang City in Henan Province, is a typical sewage irrigation area, a large area of long-termsewage irrigation led to serious soil pollution, environment and food safety issues caused byheavy metal contamination in soil urgent need to address. In this paper, geostatistics is used todiscuss and analyz the spatial variation characteristics of soil heavy metals in soil Cd ofeffective state, organic matter and pH in Xinxiang sewage irrigated wheat field in differentdepths of the clear water irrigation and sewage irrigation under different irrigation conditions,this paper provides an important basis for the soil environment, the main results are asfollows:1. Using a single sample K-S test and Q-Q test to test if the datas of soil Cd content, organicmatter content and pH value of every layer in accordance with normal distribution, on theother hand, for non-normally distributed data logarithmic transformation. On this basis,through the mean coefficient of variation, skewness, kurtosis and other statistical parametersof different indicators of soil analysis show that: the average overall clear water irrigationirrigated soil available Cd content before the irrigation is larger than the content which afterirrigation, while the case of sewage irrigation is opposite. As organic matter content of clearwater irrigation and sewage irrigation, after less than before irrigation. Layers of soil Cdcontent and organic content in the case of clear and sewage irrigation with increasing soildepth decreases, while a small range of pH value change with increasing soil depth noobvious trends. Coefficient of variation of Cd content and organic matter content before andafter irrigation in different test areas greater than10%and less than90%, which is moderatespatial variability and the coefficient of variation of pH less than10%, which is weak spatialvariability.2. The use of semi-variance optimal fitting function theory Semivariance get a different testarea before and after each irrigation different indicators of soil semivariogram model and itsparameters, the results showed that, spatial correlation of Cd concent in20-30cm layer aftersewage irrigation and organic matter content in0-10cm layer after cleaning irrigation belongweak spatial correlation, in addition, spatial correlation of pH value befor cleaning irrigationin10-20cm layer belong moderate spatial correlation, spatial correlation of Cd content, organic matter content and pH value in the rest of the layer before and after cleaning irrigationand sewage irrigation belong strong spatial correlation.3. According to the Kriging interpolation method, draw the contour maps of soil Cd content,organic matter content and pH of each different test areas on the surfer software platform,which show that spatial variability of soil Cd content, organic matter content and pH innorth-south direction in the study area belong large spatial variability. |
