Remote sensing investigation of cultivated land change in Yangtze Delta region

Abstract

It is a critical important task to find out cultivated land change quickly, as the sharply reducing of cultivated land use because of the rapid development of industry and agriculture in Yangtze Delta Region. It is satisfied well to investigate land use change with the technology of remote sensing. According to the method of view distinguishing of 'dynamic graph and point comparing,' cultivated land changes from 1992 to 1995 were investigated for every county in the region, using 1/100000 'TM' imagine data as an information source. The results showed that the cultivated land was decreased sharply as much as 61000 hectares for the region in three years. The mean changing rate was 10.8% per year. And in the three cities, Suzhou, Wuxi and Changzhou, the rates were as high as 15.6%/year. Among the decreased cultivated land, construction land was occupied as the part of 51.8 - 62%. In order to protect limited land resources, a dynamic measuring system of land use must be organized. According to the 'TM' imagine data, using the method of remote sensing measurement, a macro- dynamic change of cultivated land in the level of county can be measured rapidly. The precision can be as high as 90 - 95%. The fixed number of measuring years may be determined according to the dynamic change of cultivated land in the region. The measuring contents of dynamic land use may be expanded to classifying of agriculture, breeding, industry and fishing.