Study On The Comparison And Link Between Cultivated Land Capacity And Farmland Gradation In Hengdong County

By means of geographic information system, combining with soil science and land resources management, cultivated land capacity classification, farmland gradation were the major land projects in recent years, there are certain correlation between the two projects, but the study of the differences and relationship between them were rare. Taking Hengdong County of Hunan Province as an example, with the help of GIS, according to the farmland productivity evaluation and technical process of farmland gradation, using information research method, clustering analysis, GIS spatial analysis, fitting method, the study of comparison and link between farmland productivity evaluation and farmland gradation was carried on. The main results and conclusions were as follows:(1) The proportion of the area of first five grades to the farmland was by91.30%in farmland natural quality, but it was only74.36%in the cultivated land capacity. The results indicated that the grade of cultivated land capacity was lower by1degree than that of the farmland natural quality in Hengdong. The distribution proportion of High/medium/low grade was0.9:88.67:10.43in farmland use grades. The distribution of farmland use land was concentrated, and the grades of each region were approximate. The proportion of the area of the grade one and grade two was80.84:19.16in farmland economy grades, the locational conditions were poor, and the input was insufficient, but the potential of the land economic development was giant.(2) The proportion of the area of grades was accordant at each geomorphic type of cultivated land capacity. The influence of the different geomorphic type to the area of grades was not obvious. The distribution proportion of High/medium/low grade was3:4:3. But, the proportion had a certain fluctuation on farmland gradation, and the influence of the different geomorphic type to the area of grades was obvious.(3) From the perspective of the geomorphic type, the difference among different geomorphic type was obvious, on the whole, the distribution order was plain areas> hilly areas> mountainous areas. The differences of evaluation indicators and weights were main reasons that cause the differences of distribution, however, the differences of the evaluation object and sample points led to some differences about evaluation results at the same bulk in the two evaluation methods.(4) The link function between score of cultivated land capacity classification and farmland grades at all geomorphic type area was established with the regression analysis method. It achieved their mutual link and check.