The Research Of Agricultural Land Quantity Based On The Two Evaluation Methods

In order to evaluate and manage agricultural land scientifically,rationally,effectively, and to offer the necessary supports for theory for the sustainable utilizing of farmland resource, this paper builds two index systems for agricultural land quantity evaluation to research the evaluation of agricultural land quantity. The paper based on the postulate of agricultural land quantity evaluation, using some mathematic methods and models such asprincipal component analysis,Delphi method,analytic hierarchy process and so on. By taking Taihe County, Jiangxi Province as an example, this research gets some significative conclusion by the application of GIS. It includes:1,The evaluation method for agricultural land quantity which is based on PSR modelBased on the totally grasp of the fact of the county and a great deal of interrelated analyse , the evaluation index for agricultural land quantity is established by field survey,data analyse. The paper builds up the agricultural land quantity evaluation index which is based on"Press-State-Response"framework. The paper chooses the pollution of agricultural land,fertilizer application,population density,population growth rate,per capita of cultivated land,agricultural land area for the press index. Sates indexes include soil conditions,water conservancy condition,traffic location,yield,terrain condition. Response indexes include land utilization and planting income. The values of agricultural land quantity is got by the application of GIS, model simulating and statistical analysis. The paper receives values to different grades of indicators and computes the average. It provides the basis for the agricultural land utilization and management,environment protection.2. The evaluation method for agricultural land quantity which used the classification and gradating methodBased on the regulation of agricultural land classification and grading by the National Land Resource Ministry of China, combing the actual conditions of the county , the paper chooses to twenty-five indexes for pre-extracting indexes , included terrain,soil,location,infrastructure,transportation,resource whether are abundant or short of ,etc.. Based on the pre-extracting indexes, principal component analysis,Delphi method are used. The results showed that the indexes which are affect the quantity of the agricultural land included: soil texture,profile configuration,rate of guarantee of irrigation and drainage,organic content,thickness of soil,terrain slope,soil erosion,soil PH,land location condition,cultivation convenience condition,utilization of land condition. The research provides scientific basis and strategies for a better protection and utilization of agricultural land. It also can gives basis theory for drawing agricultural policy,building high-yield and stable-yield agricultural land .3. The comparison and analyze for the two methodsPSR model evaluation is a dynamic evaluation and causality analysis. It not only rests on the evaluation for the quantity of agricultural land, but also emphasizes the sustainable development of agricultural land evaluation. Besides the natural and location condition, It also considers the status of agricultural land which is being threatened. It can provides relational some counter measures; While classification and grading evaluation is a static evaluation which reckons without the interfering factor from human. It emphasizes the natural quality and location condition. The purpose is to give service to the evaluation for agricultural land value. So it can't reflect the sustainable development of agricultural land.