Efficiency Assessment Of Conversion Cropland To Forest And Grassland Project In The Inland River Of Hungriness Valley

Based on the study of the middle -lower reaches of Tarim River valley, using the existing styles of forests and grasses replaced the conversions. Designing a suit of assessment index which consists of water,soil,vegetation,economy. Equal variance decision-making method and principal components analysis (PCA) were used to study each index and vegetation,the eco-economy efficiency of each vegetation is counted. The aim is to provide theory and technic supporting to the project of the conversion cropland to forest and grassland project in the inland river of hungriness region in China.The conclusions suggest: 1．The weight of each index's rank is: production value of a unit of area,ratio of produce and cast,cover of vegetation,callback period of invest,exponent of diversity,deepth of groundwater,soil humus,ratio of salt area,effect of hurrince lamp,effect of sand fixation,Ph of soil,irrigation quantity of a unit of area,general salt quantity of soil,pH of groundwater,mineralization of groundwater。2．The model of assessment is: Wi=Zij·Ej。 3．The best efficiency is economic forest,the best zoology efficiency is mixed forest。The unit ha. of each vegetation style's efficiency is:mixed forest is 16140 yuan；pure forest is 15724 yuan；economic forest is 19925 yuan；pasture is 15090 yuan；cotton is 7985 yuan。4．At the current conversion scale,the zoology efficiency cne be increased 3.48×107 yuan (based on 2002),and 1.7×107 cube water can be saved,but the economy efficiency can not be improved.