重庆市地表起伏度及其对农业生产的影响分析

重庆地貌复杂多样,地表起伏度大,通过对重庆各区县地表起伏度研究和计算,可定量了解重庆山水起伏骨架指数。以空间分辨率为30m、投影为WGS84_UTM的ASTER GDEM V2全球数字高程数据为基础,在ArcGIS10.1中利用投影面积比法计算重庆各区县地表起伏度指数,在此基础上分析了地表起伏度与2008~2013年各区县农业生产指标之间的相关性并建立系列模型。结果表明:1重庆西部较为平整,地表起伏度比中、东部地区低,地表起伏度最大的是东北部的城口、巫溪、巫山,最平整的是西部的荣昌、潼南、大足。2基于重庆市31个县域的统计分析,地表起伏度标准化指数每增加0.1,粮食单产减少约0.37t/hm~2,农林水支出占财政支出比例增加约1.1%。3地表起伏度对耕播面积比例影响力最大,其可决系数R~2达到0.8859。4农业产出不变时,农业投入随地表起伏度的增加而增加,地表起伏度与综合指标(农业产出投入比)所建指数模型的可决系数R~2为0.8296。

RELIEF DEGREE OF LAND SURFACE OF CHONGQING AND ITS INFLUENCE ON AGRICULTURAL PRODUCTION

The landform of Chongqing was complex and diverse , and relief degree of land surface was great in Chongqing.By researching and calculating of relief degree of land surface of each country of Chongqing ,it can in -depth understand the topographic relief .Digital elevation model with 30 m spatial resolution and projected coordina-teof WGS84_UTM was applied in this study.Relief degree of land surface of each country of Chongqing was calcu -lated by ArcGIS10.1.The indexes of agricultural production of each country of Chongqing from 2008 to 2013 were the basic data which originated from the statistical yearbook of Chongqing .The models between the indexes of agri -cultural production and relief degree of land surface of Chongqing were built up .The results showed that:1) West-ern Chongqing was more smooth than Central and Eastern Chongqing .The largest relief area of surface was in Chengkou, Wuxi and Wushan, and the flat area was in Rongchang , Tongnan and Dazu.2) Based on the statistical analysisof 31 counties of Chongqing, the grain yield reduced 0.37 t/hm 2 , and the proportion of expenditure for ag-riculture, forestry and water conservancy in total expenditure increased by 1.1%, when the relief degree of land surface increase 0.1.3) The relief degree of land surface had the greatest influence on the proportion of sown area of the crops, and the determination coefficient (R 2 ) was 0.8859.4)Agricultural input increased with the increase of relief degree of land surface when agricultural output was constant .The exponential model (input -output ratio agriculture)between relief degree of land surface and aggregative indicator can be established with the determination coefficient (R 2 ) of 0.8296.