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浏览/检索结果: 共6条，第1-6条 帮助 限定条件 内容类型：会议论文     已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 耕作导致的土壤再分布对土壤水分入渗的影响 会议论文 2009年农业资源利用学科全国博士生论坛, 重庆, 2009-10 作者:  苏正安;  张建辉 收藏  |  浏览/下载：14/0  |  提交时间：2011/11/04 耕作侵蚀  耕层厚度  土壤紧实度  入渗  坡耕地   Land use dynamics and landscape change pattern in Hetao irrigation district, Inner Mongolia, China 会议论文 6th International Symposium on Digital Earth: Data Processing and Applications, Beijing, China, September 9, 2009 - September 12,2009 Zhang, Yinhui; Luo, Yi; Zhao, Wenwu 收藏  |  浏览/下载：16/0  |  提交时间：2014/12/07 This study analyzed spatial and temporal changes in land use in an irrigation district covering an area of 1.7 million ha in Northern China by GIS analyses and also investigated changes in landscape pattern using the landscape structure analysis program FRAGSTATS over the study period from 1986 to 2000. The decreases in farmland and the increases in grassland area mainly resulted from the policy of grain for green and converting slope farmland into pasture from China government. In spite of the efforts to conserve the fragile ecosystem  the land degradation  including soil salinization and grassland degradation  was spreading rapidly. The area of alkali-saline land increased by 22493 ha and about 50555 ha of dense grassland degraded into mid-density grassland. In terms of landscape fragmentation  both farmland and dense grassland showed the tendency of increased fragmentation. Both adverse natural conditions and human activities are responsible for the land degradation expansion in Hetao irrigation district  but the root causes are increasing population pressure and irrational human activities  such as flooding irrigation method and over-grazing. To prevent land degradation from spreading  population control and improvement of the management are prerequisite approaches. 2010 SPIE.   The Application Research of Grid Slope Filtering in Farmland Slope Extraction 会议论文 作者:  Cheng Xiong;  Wang Hui-zhen;  Wang Wei-li 收藏  |  浏览/下载：4/0  |  提交时间：2019/12/05 DEM grid size  filtering method  slope extraction of farmland spot   The Application Research of Grid Slope Filtering in Farmland Slope Extraction 会议论文 作者:  Cheng Xiong;  Wang Hui-zhen;  Wang Wei-li 收藏  |  浏览/下载：2/0  |  提交时间：2019/12/05 DEM grid size  filtering method  slope extraction of farmland spot   The Regulation of Vegetation Distribution Based on MODIS Image in Aba Prefectures 会议论文 Nanning, SEP 18-20, 2009 作者:  Cheng Wuxue;  Yang Cunjian;  Zhou Jieming;  Zhou Wancun;  Li Yue 收藏  |  浏览/下载：1/0  |  提交时间：2020/07/10 Aba prefecture  vegetation distribution  MODIS image   FTIR, TPD and DFT studies of intermediates on Ag/Al2O3 during the selective catalytic reduction of NO by C2H5OH 会议论文 8th International Congress of Ecology, SEOUL, SOUTH KOREA, AUG 11-18, 2002 作者:  Yu, YB;  Gao, HW;  He, H 收藏  |  浏览/下载：7/0  |  提交时间：2016/01/14 land-use  principal component analysis  slope position  soil nutrients  soil quality