近50a人工灌排技术进步对玛纳斯河流域耕地格局变化的影响

分析绿洲人工灌排技术发展和耕地格局变化之间的关系,对研究干旱区灌溉农业发展具有重要的意义。论文选取玛纳斯河流域为研究区,利用RS和GIS技术,对玛纳斯河流域1960年地形图,1976、1989、1997、2006、2013年Landsat遥感影像和历史水利工程建设分布图等原始数据进行处理,获得5期人工灌排渠系矢量图和6期土地利用分类矢量图,并计算人工灌排渠系长度指数和表征耕地格局的绿洲垦殖率、净耕地系数、周长面积比;利用多元逐步回归法,分析干旱区绿洲人工灌排技术对耕地格局变化的影响。结果表明:滴灌技术应用前,玛纳斯河流域耕地分布格局由灌排渠系的空间分布决定,尤其是农渠的分布格局和长度,其与耕地面积的回归方程为y=0.43x+7.38(R~2=0.90,n=33,P=0);滴灌技术应用后,耕地分布格局的变化取决于滴灌系统管网的空间分布,尤其是干管和支管的分布格局与长度,导致流域灌溉水利用系数从1960年的0.38增长到2010年的0.65。

Effect of Progress in Artificial Irrigation and Drainage Technology on the Change of Cultivated Land Pattern in the Past 50 Years in Manasi River Watershed

The analysis of relationship between artificial irrigation and drainage technology development and cultivated land change pattern has vital significance in the research of irrigation agriculture development in arid areas. Manasi River Watershed was taken as the study area. The topographical map of Manas River Watershed in 1960, remote sensing images taken in 1976, 1989, 1997, 2006 and 2013, historical maps of water conservancy, and other original data were processed by remote sensing image possessing and spatial analysis in geographic information system, and the artificial irrigation and drainage canal system at five stages and land use classification in six periods were obstained. Then the length index of artificial irrigation canal system and the indices describing cultivated land pattern, i.e. oasis reclamation rate, net cultivated land coefficient, perimeter-area rate, were calculated. Finally, stepwise regression method was used to explore the effects of artificial irrigation and drainage technology on the change of cultivated land pattern. The results showed that: before the application of drip irrigation, the distribution pattern of cultivated lands in Manasi River Watershed was determined by the spatial distribution of irrigation and drainage canal system, especially the distribution pattern and the length of sublateral canals, the regression equation being y=0.43x+7.38 (R²=0.90, n=33, P=0). After the application of drip irrigation, the change pattern of cultivated lands was determined by the distribution of pipe networks of drip irrigation, especially the distribution pattern and length of main pipe and branch pipes, resulting in the increase of water use efficiency from 0.38 (1960s) growth to 0.65 (2010) in the watershed.