An alternative to the Grain for Green Program for soil and water conservation in the upper Huaihe River basin, China

Study region: The Xixian Watershed is an agricultural watershed in the upper Huaihe River basin, China, which suffers severe soil erosion. Study focus: Converting the types of agricultural production without losing their agricultural purposes would be a choice for mitigating soil erosion compared to the Grain for Green Program (GGP). The Conversion of Land Use and its Effect at Small regional extent (CLUE-S) model and the Soil and Water Assessment Tool (SWAT) model were used, and four land-use scenarios (S1: preference for dry land; S2: historical trend; S3: preference for paddy land; and S4: grain for green) were designed based on different preference in agricultural land and the GGP. The responses of runoff, sediment yields, and economic benefits were compared under each land-use scenario. New hydrological insights for the region: We find that S1 increases runoff and sediment yields, S3 and S4 decrease runoff and sediment yields, and S2 slightly increases runoff and reduces sediment yields. Different types of agricultural land mainly affected runoff by redistributing surface and subsurface runoffs. Paddy land would increase subsurface runoff and decrease surface runoff and sediment yields, in contrast to dry land. The economic benefit could be increased under S3 and be opposite under other scenarios. Promoting paddy farming in a water-rich watershed can mitigate soil erosion, conserve groundwater, and gain more economic benefits simultaneously.