基于遥感影像的决策树分类,结合土地利用图,将北京市农业地表覆盖划分为春玉米、冬小麦、果园、林木苗圃、牧草地、设施农业和畜禽饲养地.考虑海拔、坡度和土壤质地三个因子将北京市分成10个景观区,在景观分区和不同农业用地基础上划分出39类农业景观单元.利用基于遥感影像计算的归一化差异植被指数,结合实地调查验证,分类出北京市冬春季裸露农田.结合景观分类,分析了不同景观单元冬春季地表裸露情况.结果表明:2007-2008年冬春季裸露农田共8.05×104 hm2,主要分布在延庆盆地、密云水库北岸和城区边缘的近郊农业区；海拔和土地利用方式对裸露情况影响较大,其中山区春玉米和平原果园裸露情况绝对面积较大,分别占到总裸露农田面积的40％和17％,牧草地、林木苗圃与设施农业地裸露程度较高.基于不同景观单元裸露程度,结合绿肥种植、保护性耕作、生草覆盖等裸露农田治理方法,探讨了北京市农业产业和景观一体化建设策略.%Agricultural land in Beijing was classified into spring maize, winter wheat, orchard, nursery, grass land, greenhouse and animal husbandry lands by integrating remote sensing data and land use map with decision tree classification method. 10 agricultural zones were generated according to the environmental factors of elevation, slope and soil texture in Beijing, and 39 types of agricultural landscape units were conducted by overlaying the different landscape zones and agricultural land use. The bare land in each agricultural landscape type during the winter and spring was investigated based on the normalized difference vegetation index maps calculated from satellite images, and validated by the field survey. The bare land in different landscape types during the winter and spring was analyzed according to the landscape classification. The results showed the total area of agricultural bare land duringthe winter of 2007 and the spring of 2008 was 8. 05 × 101 hm2, and the agricultural bare land mainly located at the Yanqing Basin, north bank of Miyun Reservoir and the suburbs; elevation and land use were the most important factors on the vegetation cover of agricultural plots during the winter and spring, and the areas of bare land of spring maize plots in hill and orchard in plain were large, and 40% and 17% of total agricultural bare land in Beijing, respectively; bare level of tame grassland, nursery garden and facility agricultural lands was serious. Based on the agricultural bare land analysis of different landscape unit, green manure plantation, conservation tillage and grass cover were used to improve bare soil, and policy suggestion for building agricultural industry and landscape integration in Beijing were put forward to.
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