Characters of natural resources and environment of ecotone and its countermeasures of sustainable development

Ecotone is a transition belt between cultivation area and grazing area with special characters of resources and environment．The counterm easures of sustainable developm ent in those areas are to break the closing state of the system ，to introduce negative entropy in order to promote the system from a low stage to a high stage，to restructure the regional agriculture and economy to couple cultivation and husbandry SO as to optimize the allocation of resources of the system ，to encourage the opening to the whole country and the world in order to input energy，mass and inform ation，and to develop new jobs and livelihoods．