Assessment of Soil Conservation Function of the Ecosystem Services on the Loess Plateau

Taking the amount of soil conservation as the assessment indicator, with the application of the Revised Universal Soil Loss Equation, the soil conservation function of the ecosystem services on the Loess Plateau in China was assessed. The spatial distribution of the amount of soil conservation and its dynamic changes on the Loess Plateau in nearly 20 years was analyzed, which has significantly scientific and practical values in ecological benefits for vegetation reconstruction under the warming and drying climate. The results showed as follows. The per unit area soil conserved on the Loess Plateau was 305 t·hm-2·a-1 between 1990 and 2010, and the total amount of annual soil conserved was 190 × 108t. The per unit area soil conserved amounts of farmland, grassland and forest ecosystems in 1990-2000 were 249, 285 and 640 t·hm-2·a-1, respectively, increased by 14.6%, 2.9% and 7.4% in 2000-2010. The percentage of soil retention rate of grassland ranged from 83% to 88%, for forest from 94% to 97% in 1990-2010 on the Loess Plateau. The characteristics of spatial distribution of soil conservation for farmland ecosystem showed that it was the highest in hilly and gully region of the Loess Plateau, and the lowest in agricultural irrigation region and the plain area. The spatial distribution characteristics of soil conservation for grassland and forest ecosystems showed a reduced trend along the southeast to northwest. Compared in 1990-2000, the amount of soil conservation for farmland, grassland and forest ecosystems showed an obvious increment in 2000-2010, especially in the hilly region in Yulin and Yan'an in Shaanxi Province and Luliang Mountain areas in Shanxi Province.