Value Estimation of Conserving Water and Soil of Ecosystem in China

Soil and water resources are important material basis for human life.As an effective means of human intervention,the value of soil and water conservation ecosystem services has been given more and more attention.In this paper,the value of conserving soil and fertilizer and the value of conserving water were selected as the indices of the value of conserving soil and water.Integration of remote sensing data,meteorological data and ground data,the original soil and water conservation service evaluation model is improved.The value of conserving soil includes three types,i.e.conserving soil fertilization,reducing surface soil loss and alleviating sedimentation.As the key point of estimating the value of conserving soil,in this paper,the USLE model was improved to estimate the quantity of soil conservation.The value of conserving water was estimated by the method of shadow engineering through expanse of building reservoir with the same water storage.Utilizing RS and GIS technique,quick estimation can be achieved through IDL programme.There are some uncertainties existing in this estimation.Firstly,the basic data are not completely consistent with the actual land surface.Secondly,some experience models adopted are difficult to reveal the soil erosion physical process.Result shows the value of conserving water and soil of ecosystem in China was 16760.55 billion yuan in 2001,including 9663.50 billion yuan of conserving soil and 7096.55 billion yuan of conserving water.According to spatial distribution,it descended from south to north.According to land cover,evergreen broadleaf trees were the highest of average value,water body less,barren and ice the lowest.According to terrain,with the higher altitude,the value of conserving soil and water showed a downward trend.According to administrative,Guangdong was the highest of average value,Xinjiang the lowest,and provinces in eastern and southern parts of China were higher than others.It is difficult to get the measured data to verify the estimation result and has no comparability to the related research,based on different methods and different indices.In the future research,the verification needs to be strengthened.