Establishment Of Evaluation Index System Of Farmland Fertility Based On GIS

Land is the valuable resource of economic and social development and important factor of production as well as the material basis of human survival. Besides, land resources are typical of the versatility of natural resources, and with the development of population and economical society, it has suffered pressure from demands coming from many kinds of sectors. Especially, in China possessing rapid economic growth rate, land resources, particularly, the arable land resources have been experienced unprecedented changes under the pressure of this kind of demand. Therefore, it is no doubt that arable land resources are the foundation of national economic, and the security of arable land resources is the prerequisite for the healthy advancement of national economic.Since "survey and quality evaluation of farmland fertility" project was launched by Ministry of Agriculture, standards of it have been gradually formed after years of research and exploration. Consequently, the breadth and depth of theories, methods, and applications on evaluation of farmland fertility have been developed immensely. However, there are still urgent problems to be tackled and consummated due to the complexity and regionalism of object evaluated, such as how to determine the index of assessment as much realistic as possible in view of different areas, the sampling density of evaluation of farmland fertility, and whether the results of interpolation is suitable for the application on the techniques of soil testing and fertilizer.In the procedure of assessment of farmland fertility, the provinces and cities make the countries'soil as the fundamental unit for the soil evaluation, and meanwhile, each of countries must generate their own index of evaluation. Because of the subjectivity of the construction of the index system for land assessment and possibility that experts have their own views towards the index influencing the appraisal of the farmland fertility, chances are that there are likely different options of index of two countries which have the same topography, climate condition, or that the different weight of the same index.Scholars have preliminarily summarized the index of evaluation on farmland fertility of Hubei Province. According to topological features, Hubei Province has been divided into six typical region, including Jianghan Plain, Eastern Plain in Hubei along the Yangtze River, mountainous region in the northwest Hubei, mountainous region in the southwest of Hubei, hillock in the north of Hubei, Hill hillock in middle region of Hubei.Employing the comprehensive system of indicators and soil science theory of the county and city in Hubei and based on the analysis of the cause of the structure of the index system and of the factors, the article attempted to establish the index system of the three types of soil fertility-plain lake, hillock, and hilly areas.Based on the principle of assessment of farmland fertility and the research of the evaluation of farmland fertility taking six countries in Province Hubei, City Jingzhou for examples, employing fuzzy mathematics, analytic hierarchy process, delphi method, and cluster analysis as well as the technology of GIS and soil science knowledge, the paper attempts to establish a uniform index system for the assessment of farmland fertility in Plain Jinghan. Exploiting the custom experience, analyzing the indexes about geomorphology, paternal material, climate and soil nutrient, and combining the methods of analysis of mathematics make successful the construction of index system of regional assessment of farmland fertility. The system have 11 indicators, including the organic matter, phosphorus, potassium, zinc and effective, texture, pH, profile configuration, landform type, soil parent materials, guaranteed rate of irrigation and drainage capacity. Finally, with the study of actual situation, the paper points out how to determine quantitative and qualitative indicators.