SOIL GEOCHEMISTRY AND NUTRIENT EVALUATION IN GUYUAN CITY OF NINGXIA

The geochemical characteristic parameters of soil element indexes are obtained through statistic analysis and iterative elimination of outlier data based on the 1 : 250 000 land quality geochemical survey and test analysis results of 53 element indexes of 2 638 soil samples in Guyuan area of Ningxia. The abundance and deficiency of 19 soil nutrient element indexes such as N, P, K and organic matters are analyzed and evaluated according to the background values of soil geochemistry, and the element indexes are then classified in terms of the nutrient status. It is found that the contents of N, Ge, Se and organic matters in the soil are relatively deficient, while CaO and MgO are abundant, which provides basis for rationally guiding sustainable development and utilization of cultivated land resources.