Evaluations of water yield and soil erosion in the Shaanxi-Gansu Loess Plateau under different land use and climate change scenarios

Abstract

More water yield and less soil erosion are crucial to the sustainable development of the Loess Plateau and Yellow River basin. Different land use policies and climate change scenarios may have great implications on water yield and soil erosion. In this paper, four land development scenarios and two climate change scenarios are designed and applied to the Shaanxi-Gansu Loess Plateau. The InVEST model is applied to quantitatively evaluate the water yield and soil erosion modulus in 2030. It showed: (1) Arable land and grassland is always the dominant land types in the Shaanxi-Gansu Loess Plateau and cover more than 76% of the area. The business-as-usual and ecological protection priority scenarios may lead to increases in the local food security risks, with 1.9% and 1.4% gaps in the total food requirements. (2) Under the RCP2.6 scenario, the annual water yield and annual soil erosion amount increased by more than 63% (2.84*109 m3) and 22% (96.0*106 t), respectively. Under the RCP4.5 scenario, the annual water yield and annual soil erosion decreased by more than 48% (2.17*109 m3) and 26% (114.3*106 t), respectively. (3) The influence of climate change on water yield and soil erosion is far greater than that of land use change. The contribution of climate change to the water yield changes is 92.8–99.6%, while the contribution of land use change is 0.4–7.2%. The contribution rate of climate change to soil erosion changes is 84.8–91.1%, while the contribution rate of land use change is 8.9–15.2%. The key ecological services, such as food production, water yield, soil and water conservation, should be carefully weighed and coordinated in the Loess Plateau and areas with limited land surfaces, such as small island development states.