Spatial Variability Analysis And Quality Evaluation Of Soil Nutrients In Urban Verge Zone

According to incomplete statistics, about 15 percent of the world's food from farmers with urban, peri-urban agriculture with the development of sustainable development for the city to provide the necessary protection. However, from industry, agriculture, transport and urban life multiple pressure on the environment, urban edge with the quality of the soil decreased significantly, So the urban fringe soil quality status, to protect human health and maintain the sustainable development of agriculture is of great significance .In this study, Geostatistics (GIS) and GPS combination of methods, to the eastern outskirts of Changsha City soil as the main study, using 150×150m grid layout point of 0-20 cm topsoil to take soil samples 71, Through analysis of soil organic matter, total N, total P, total K, available N, available P, available K, slowly available K, pH value, such as nutrient content,, The research discussed the spatial distribution character and the disciplinarian variance. Simultaneously, evaluating factors of soil fertility quality were selected in research region, by use of Fuzzy comprehensive assessment the research region comprehensively evaluated soil fertility quality. After the evaluation showed those results:1. Examining normal distribution of the soil nutrient. Soil organic mater, total N, total P, available N, available P, slowly available K and <2μm Clay presented close normal distribution, soil total K, available K and pH presented logarithmic normal distribution; The variable coefficients of all types nutrients are in the range of 15.67%-61.29%, belong to medium variance.2. Used the geo-statistics and GIS analyzed various soil fertility parameters of east-suburb area soil in Changsha district. Found those, the theoretic model of the soil organic mater, total K, available N, slowly available K, pH were spherical. The theoretic model of the soil total N, available P and available K were exponential. The theoretic model of the soil total P, and <2μm Clay were Gaussian. The nugget coefficient of total K and slowly available K are lower than twenty-five percent, which show its strong spatial correlations; while that of organic matter, total N, total P, available N, available P, available K, pH value and <2μm Clay are in the range between 25%-75%, which show their medium spatial correlations3. Different types of land-use samples of soil fertility characteristics are as follows: The fertility quality of east-suburb area soil in Changsha could be generally summarized as, soil pH is nearly acidity; total P,K, available P and slowly available K content was high, the total N, available P,K content was medium on, but organic matter were not rich. The results of evaluating on the soil fertility quality by use of the Fuzzy comprehensive assessment showed: all of the soil fertility quality belonging the middle level, the woodland,wasteland of Donghu Heping and wasteland of Tanyang soil fertility quality belonging to the 3 grade of the lower fertility, the upland of Donghu Heping and upland,woodland of Tanyang soil fertility quality belonging to the 2 grade and the higher fertility.The application of the best interpolation of Kriging to protract the map of soil nutrients can reveal relationship between soil nutrients and soil parent materials and land-use types more subtly and intuitionisticly. In order to avoid the harmful effect of average fertilization, which does not thinking about the discrepancy of soil nutrients, it also can provide scientific reference for subtle fertilization of suburb agriculture.