The Evaluation Of Cultivated Land Natural Quality Grade Based On GIS And GRA Model

In order to scientific and effective management of cultivated land resources, Grasp the "quality" and "quantity" change trend of cultivated land in the county, To ensure land resource management is effective, timely and forward-looking. It is necessary to cultivated land natural quality evaluation, is of great significance to the management of cultivated land quality construction and cultivated land protection. At present, the quality evaluation of cultivated land in the county is generally recognized according to the "standard methods for farmland grading rules" in the evaluation. The evaluation is mostly used the AHPand PCA method, in the selection of indicators and the calculation of the weights, is easy to be affected by the factors of human subjectivity, results lack of objectivity. Therefore, in this paper, through the introduction of GIS technology and the theory of Grey system, study the establishment of farmland natural quality evaluation of GIS and GRA based on the method of model, and take Jiangxi County of Yiyang Province as a case study.In this paper, the application of gray correlation analysis and modeling method to evaluate the natural quality of cultivated land. To evaluate the first reviews the domestic and foreign research present situation and the relevant theoretical research, this paper establishes the theoretical basis and guiding ideology. Secondly, collecting the necessary data, using ArcGIS, MapGIS, Microsoft Excel and other software to establish a database on the basis of evaluation and make full preparations for the beginning of the experiment. Then by constructing the evaluation of cultivated land quality of Grey relational analysis model to select evaluation factors, calculate the correlation degree and the weights of evaluation factors according to the formula, based on the correlation results are sensitive to sort the factors. Finally get the evaluation unit of natural quality grade according to the method of agricultural land classification and gradation. The results of this study,cultivated land National Nature Grade in Yiyang County are mainly distributed in 8 to 12, with 9 of the most widely distributed, covers an area of 15898.96 hectares, accounting for 48.18% of the total cultivated area of the county; The 12 area is less, mainly distributed in the Town of CaoXi,QiGong,SanXianLing comprehensive reclamation farm, ZhongBan, an area of 359.04 hectares, accounting for 1.09% of the land area of the county. The paddy fields are mainly distributed in 8 and 9, accounting for 82.23% of the total area of cultivated land in Yiyang; Dry land is mainly distributed in the 10 and 11, accounting for 8.45% of total area of cultivated land. On the whole, the natural quality of cultivated land in Yiyang County, belongs to medium. Yiyang County Land factors correlation ranking results are as follows:Paddy field : Irrigation guarantee rate>Content of soil organic>Soil texture>Profile configuration>drainage condition>Soil PH; Dry land:Effective thickness of soil layer> Irrigation guarantee rate> Content of soil organic> The terrain slope> Soil texture>Soil PH...