Evaluation of soil conservation function and its values in major eco-function areas of Loess Plateau in eastern Gansu province

Under the support of RS and GIS technology, with integrated application of the revised universal equation on soil loss, market value approach, opportunity method and alternative engineering strategy, the soil conservation function of the ecosystem of major hilly-gully eco-function areas in Losses Plateau of eastern Gansu province and its economic value were assessed in this study. The results show that from the year 1986 to 2006, the amount of soil erosion major hilly-gully eco-function areas in Losses Plateau of eastern Gansu province has gradually increased, while the amount of soil conservation and the total value of its function have obviously decreased. The amount of soil conservation were 38956×104、37834×104、34359×104 t in the year 1986, 1996 and 2006 respectively, with total economic value of soil conservation as 230.26×108、223.63×108、203.09×108 Yuan. Among the total value of soil conservation, the soil conserves potassium got the highest economic value, accounting for 96.41% of the total, while the soil conserving organic matter had the lowest economic value, only accounting for 1.52%. There was a significant spatial difference on soil conservation function in this area. In the east, most regions' soil-conservation function is more than 15000 t/(km2·a), while in the north and southwest, the predominant parameter was under 1 000 t/(km2·a). The results can be used for the area ecosystem conservation and management.