河西走廊3县草地资源现状及生产力评价

Evaluation on Actuality and Productivity of Arid Grassland Resources in the Hexi Corridor of Gansu Province Using 3S Technology and Field Survey

借助3S技术的一体化集成平台,以陆地卫星的TM影像为数据源,结合地面样地和路线调查,参考相关专业图件,完成了永昌县、甘州区和肃州区天然草地类型划分、植被指数提取、草地产草量估产模型构建及产量估测。将3县(区)天然草地划为6个草地类(含亚类),包括温性荒漠草地类4.75×105hm2(占71.48%),温性草原草地8.32×104hm2(占12.51%),低平地草甸草地4.69×104hm2(占7.04%),高寒灌丛草甸草地2.73×104hm2(占4.10%),温性荒漠化草原草地2.54×104hm2(占3.83%)和高寒草甸草地6911hm2(占1.04%)。3县(区)各类草地理论载畜量为1.77×105羊单位,实际放牧家畜约2.71×105羊单位,超载53.16%。与20世纪80年代相比,3县区天然草地承载力均出现了不同程度的下降。

In this study,the Landsat TM images are used as the data sources to classify the types of natural grasslands,extract the vegetation indexes,and develop the models for estimating the edible herbage yields of the natural grasslands in Yongchang County,Ganzhou District and Suzhou District in the Hexi Corridor of Gansu Province using the integrative technology of RS,GIS and GPS based on the field survey and the references of the related maps and knowledge.The natural grasslands in the study area are classified into 6 types including the temperate deserts（4.75 ×105 hm2,71.48% of the total）,temperate steppes（8.32 ×104 hm2,12.51%）,low-flat meadows（4.69 × 104 hm2,7.04%）,high-cold shrub-meadows（2.73 × 104 hm2,4.10%）,high-cold meadows（6 911 hm2,1.04%）,and temperate desert steppes（2.54 × 104 hm2,3.83%）.The theoretical carrying capacity of all the grasslands in the study area are 1.77 × 105 sheep units,but the actual livestock are 2.71 × 105 sheep units,and the overgrazing rate is as high as 53.16%.The carrying capacity of the natural grasslands is decreased in varying degrees compared with that in the 1980＇s.