Establishment And Application Of Soil Information System In Shaanxi Province

The conflict issues between ecological environment and human activities has been widely concerned in the world, for example, the reduction in cultivated land resources, decline of soil quality and the rapid growth of population. With the development of soil science, computer technology and its interdisciplinary, the applied field of soil science has been extended a large. Forth more, soil information system has become a hot topic in academic research in recent years. Studies from different aspects have shown that application of soil information system not only improves the effective in soil monitoring, mapping and modeling level, but also strengthens the soil science research and application.In China, the common soil resources data in the management is isolated and dispersed relatively lower level and poor exchange channels in dada usage at the same time. Whilst, with the development of soil survey, a great deal of information is accumulated and how to improve information management level of soil resources has becoming a pressing problem. In this thesis, "Shaanxi soil", "Second soil survey data set of Shaanxi Province", "Shaanxi Native Soil" and the soil testing and fertilizer program data from Ministry of Agriculture are referenced, based on the SOTER database technology, comprehensive soil information system of Shaanxi Province is designed and developed. Simultaneously,Soil types with its spatial distribution pattern, spatial distribution of soil nutrients, soil quality, soil organic carbon density with its spatial distribution, the temporal variability of soil nutrients of Shaanxi province are been analyzed and evaluated. Following with main conclusions:Firstly, Soil Information System of Shaanxi Province is designed and developed. Using C# programming language and the ARC Engine development approach, with the help of the idea of project management, Soil Information System of Shaanxi Province is designed and developed based on the COMGIS technology. The system has the function of design, editing, storage, statistics and analysis and others, it is more practicable for soil information management and precision agriculture research for the future.Secondly, Shaanxi Province soil types with its spatial pattern are comprehensively analyzed. Include: (1) soil type spatial distribution and formation characteristics; (2) landscape distribution patterns of soil types about the area characteristics, morphological features and its major soil feature; (3) the soil fractal dimension distribution based on the fractal theory and GIS technology; (4) the sort of soil structural stability for quantitative description of different soil types.Thirdly, the spatial distribution of soil nutrients was explored. Based on 1:250 000 topographic maps, a digital elevation model of Shaanxi Province (DEM) is established. According to the landform features, with a overlay and integration with slope map and soil nutrients map, spatial distribution characteristics about altitudes gradient, slope gradients and soil organic matter, soil total nitrogen, total potassium, soil pH, 4 kinds of soil trace elements are been thoroughly deducted.Fourthly, the quality of soil fertility is evaluated. With the methods of GIS spatial analysis and the superposition of various evaluation factors, the formation of soil fertility evaluation unit is deducted. While AHP method is adopted to achieve fertility evaluation by determining the weight of each factor.Fifthly, the content of soil organic carbon density is estimated. According to the second soil survey outputs and the 1: 500 000 soil map, soil organic carbon density and storage, as well as spatial distribution of Shaanxi province are preliminaryly estimated.Sixthly, Heyang County in Shaanxi Weibei Plateau is taken as special case, spatial variation of soil nutrients are analyzed. Using GIS geostatistics spatial analysis techniques, the soil nutrient content in the past 23 years of Heyang County is analyzed.