1.Institute of Soil and Water Conservation,CAS & MWR,Northwest A & F University,712100,Yangling,Shaanxi;2.Institute of Geographic Sciences and
Natural Resources Research,CAS,100101,Beijing: China
Abstract：Based on the summarizing of domestic researches on natural soil erosion amount and soil loss tolerance,the relationship between them and the criterion of soil and water conservation were discussed.There are 3 reference values for ascertaining the criterion of soil and water conservation: 1)standard value,i.e.soil loss tolerance,it is the goal that soil and water conservation at least need to achieve,and it is dissimilar with the function demand and enforceable optimal control measures of different land use,along with the risk of soil erosion and restriction for soil and water conservation in different regions;2)ideal value,i.e.the soil loss amount in well-balanced natural condition;3)extreme value,i.e.no loss of soil and water.The soil and water loss should be firstly controlled within the range corresponding to the ecological environment and social economy of the time,then gradually down to natural soil erosion,or even to no of loss of soil and water loss;the idea of environment ethnics,environment esthetics,and landscape design also should be introduced in the implementation of soil and water conservation,to ultimately actualizing the sustainable land use,healthy and stable regional ecosystem,and harmonious human-nature development.
2008, Vol. 6 
