Spatio-Temporal Evolution Analysis Of Soil Fertility Quality In Datong For Recent 20 Years

Geostatistics combined with GIS was applied to analyze the spatio~temporal change laws of soil nutrients in topsoil (0~20cm) in Datong of Shanxi province. Soil nutrients in this study included organic matter, total N, total P, available P and available K. The main results are as follows:(1) the statistic result of soil nutrient has showed that the organic matter, total P and available P of soil surface have increased respectively in Datong, however, the total N and available K have decreased. The increasing of total P and available P is mainly relevant with the application rate of fertility, but ignoring the N and K have resulted in the reduce of soil N and K(2) the result have showed by comparing the spatial distribution map at two period that the soil organic matter content increased by 0~5g/kg covers the area of 32.27 percent of total area, reduced by 0~6 g/kg covers the 44.5 percent of total area. The total N has decreased and reduced by 0~0.1 g/kg covers the 50.81 percent of total area, reduced range larger than 0.1 g/kg covers the 24.91 percent of total area. Only 21.28 percent area has increased. The total P has a increasing trend, increased by 0~0.25 g/kg covers the 68.78 percent of the total area. The available P is the same as the total P but the increased range is larger. Only 3.4 percent area is reduced and increased by 0~10 mg/kg and 10~20 mg/kg cover the 80.16 percent of total area. In addition, increased by more than 20 mg/kg covers the 16.26 percent area. The available K has decreased, reduced by 0~20 mg/kg and 20~50 mg/kg cover the 57.80 percent of total area, increased by 0~20 mg/kg and 20~40 mg/kg cover the 35.46 percent of total area.(3) the study of soil fertility quality under different land use pattern have showed that people's tillage, land use pattern and the field management are important factors among many influence factors of soil fertility quality. With the increasing reclaim extent and lengthening reclaim time in mountain and hilly areas , there is degrading soil organic matters, serious water loss and soil erosion, soil desertification and soil fertility quality deteriorating. In the future we should not only strengthen the build of basic farmland but also return farmland to forest and grass lands, then forming animal agriculture base. Farmland mainly is distributed in plain areas, Fertility of soil often is limited by the land use pattern and the level of management. The change of soil quality in the water~irrigated farm, dry farm and vegetable plots is mainly depended on the man's management and input level. And in the good tillage and high input farmlands the soil fertility quality is obviously increased. Therefore, there is important to keep the high fertility soil and improve the low fertility soil.