关键词: InVEST模型, 土壤保持, 生态效益, 榆林市

Abstract: As is well known to all that water and soil loss is the most serious ecological problems in the Loess Plateau, so it is of great significance to evaluate ecological benefits of soil conservation. Taking Yulin as an example, InVEST model was used to evaluate ecological benefits of soil conservation of Yulin city from 2000 to 2010 in the paper. And its evolution law and spatial pattern characteristics has been found. The results showed that: ① From 2000 to 2010, it has showed that the soil conservation quantity increased firstly and then decreased, and the soil conservation ecological benefit had a declining trend. For the annual mean soil conservation ecological benefits, it had more than 1.19×10¹¹ billion yuan. Both soil conservation quantity and soil conservation benefits, Shenmu County was the biggest, and Wubu County was the minimal. ② The soil conservation ecological benefit space distribution in Yulin exhibited a decreasing trend from northwest to southeast and the value of river upstream and midstream is higher than downstream. The value of northern six counties was much higher than that of southern counties. ③ Soil conservation quantity and its ecological benefit had obvious difference, which difference may attribute to several factors as topography, land-use pattern, soil physical and chemical properties, ecosystem type and vegetation cover, as well as land area. Especially, the size of the land area had a great effect on both the total soil conservation quantity and soil conservation ecological benefit. That was why the total of the six counties in the south was smaller than north.

Key words: InVEST model, soil conservation, ecological benefits, Yulin city