Studies On Reasonable Distance Of Farmland Classificiation And Gradation

Farmland classification based on the nature, socio-economic attributes and the needs of management is a work which evaluates the quality of agricultural land. It is an important part of the land resources survey. As the development of Chinese land management system, the agricultural land implementation of laws and regulations, land requisition compensation and protection of farmland, land improvement, and the development of arable land, these want a scientific approach to assess the quality of agricultural land.In recent years, land evaluation studies is gradually deepen. People pay more and more attention to the evaluation application and veracity. The agricultural land classification widely carried out in the country and have achieved out standing results. Huai'an county is the study area of the disquisition. It is according to agricultural land classification of order to constructing indexes of agricultural land classification system and calculate classification index quantity. In the end the disquisition expounded how to build classification database to based on MAPGIS. According to classification results, it is based on the economic classification quantity and grade quantity datum. It used the distance analysis of the correlation analysis and T-test, to have the difference analysis between the economic classification quantity and the grade quantity datum by using SPSS software. It is to study the distance of the classification and the distance of the grade and the number of the classification. Its aim is the classification results more scientific and accurate, more effective in practical application and the purpose of improving the results.Frist there are the classification of the basic theorys and methods in this paper. Second, it research into the regional characteristics of and the grades on the basis of MAPGIS software. The county infields were divided into six natural classification, eight using classification, six economic classification and four grades. The calculation of the natural classification quality and the grade quality used the index method. It ensures that the datum can be compared. Third, using SPSS software, it analyzed the difference of the sequential economic classification qualities and the sequential grades qualities by the distance analysis from a macro perspective. Finally, it made section line from the northwest to the southeast in Huai'an County .The line should go through the section of the most township, the most terrain, the largest number of grades and classifications. Then it select the terrain, soil thickness, soil surface texture, organic content, guaranteed irrigation rates and standard grain yield. And it researched the adjacency fields of the difference belong to the different classifications and grades by the t-test method.The results show that: By analyzing the levels of external and internal differences, we can see the difference of classification in the level of external and internal similar large. The classification not only highlights the level of external differences, also ensured that the internal similarities, not only distinguish the quality of the land, also ensure the accuracy of the division. Therefore, classification is more reasonable. Grading difference of external and internal similarities are small. It did not reflect differences in the quality of land and its division is too small. Classification is comparable in county, grading is comparable in the country. The number of classification levels within the county has reflected the difference and similarity, then the internal differences should be ignored in a wider place. Therefore, the grades should be reduced. Not reduced numbers of grade should be less than the number of classification. Finally in this paper, two amendments are proposed and verified. Then Huai'an County Farmland reasonable quantity and the way of grading are given.