Agro-forestry ecosystem and sustainable development of agriculture in Karst regious-Taking Zerong Village of Xingyi City of Guizhou Province as an example

The features of agricultural ecological conditions in Karst regions in Guizhou Province．the structure and function and the eeologieal，economical and social benefits of the integrated agro-forestry ecosystem in Zerong Village are analyzed．The results demonstrate theoretically that the integrated agro-forestry ecosystem is an effective way to develop sustainable agriculture and to improve people’s living condition．