Gis-Based Evaluation And Dynamic Of Soil Fertility And Its Application Study In Xiangshui County, Jiangsu Province

As the nucleus of the land, cultivated land is the basic resources for the agricultural production. The dynamic of soil fertility has direct influence on the sustainable development of agriculture and food security. Thereafter, it is very desirable to develop the work on evaluation of soil fertility and classification for agricultural land. Meanwhile, it is very essential to analyze the trends of soil fertility and present corresponding policies and measures. On the whole, this is an important measure to protect arable land, especially basic farmland, improve their quality, and expand overall grain production capacity. Also, the practices have important theoretical and realistic significance in agricultural production.In this paper, the Xiangshui County, Jiangsu Province was selected as the study area. Supporting with the GIS, the maps of agricultural soil, block diagram of basic farmland protection, and present land-use were used and then added them together to produce the delineation of soil. Next, we selected13affected factors in this county from four elements:nutrient status, barrier of soil profile, physical and chemical properties, and soil management. On the basis of analysis of these factors, this paper is combined Delphi method, Fuzzy math, and with the theory of Analytic Hierarchy Process to get an overall evaluation and classification of soil fertility in Xiangshui county. The results indicated that the basic cultivated farmland in the county can be divided into4grades. Overall, the grades in most of the whole county were middle or high. Among it, the area of cultivated land at the second and third grade accounts for39.3%and46.9%of total cultivated area, while the percentage at the first and fourth grade was only1.9%,22.12%and6.66%, respectively.According to evaluation data of soil fertility in1984and2010, we comparatively analyzed the dynamics of soil nutrients in Xiangshui County. The data analyzed includes soil organic matter, available phosphorus, available potassium, pH and topsoil thickness. Accordingly, the cultivated soil properties had also changed. At the same time, each index of soil nutrient had great change. Also, it had a bit of difference in various soil type and soil nutrient in each village. Overall, the trends of soil fertility in this county showed enhanced. Thereafter, we proposed several measures in practices, such as application of organic fertilizer, carrying out soil testing and formula fertilization, deep ploughing and subsoiling, systematic monitoring of land quality, and so on.