Spatiotemporal Pattern Variation of Cultivated Land Resource in Area of Middle and Lower Reaches of Jialing River

Based on the technology of GIS and RS,applying the land use coverage data and DEM,the status of cultivated lands,and relations between the cultivated lands and landform in the areas of the middle and lower reaches of the Jialing River were analyzed,we also investigated spatiotemporal variation trend of cultivated land resources in the past 50 years.Results indicate the cultivated land area decreases abruptly after a long-term increase,but structure of the increased lands is unreasonable.So we must pay attention to both quantity and quality,which helps to the ecological environment construction,cultivated land resource uses,reforesting formerly cultivated land inspection,food security and so on.