Mismatch between provincial grain production and consumption increased cropland soil erosion in China

Cropland soil erosion is primarily caused by agricultural production and indirectly altered by consumption patterns. A well-developed grain trade system transfers grain products to distant locations, away from their place of origin where soil erosion may have occurred. Evidence-based policies to control soil erosion can be developed by holding consumers responsible for the soil erosion caused by their consumption. However, there have been few systematic studies on cropland soil erosion that is embodied in grain trade. In this study, we estimated the soil erosion intensity (SEI) of grain production in each province of China from 1990 to 2020 by combining the Revised Universal Soil Loss Equation and socio-economic statistics. We also constructed an interprovincial grain trade network using linear programming techniques and analyzed the cropland soil erosion associated with the interprovincial grain trade. The results showed a rise in national cropland soil erosion attributed to grain production from 5.36×108 t in 1990 to 7.56×108 t in 2020. In particular, those embodied in interprovincial grain trade increased from 0.94×108 t in 1990 to 3.52×108 t in 2020. Nationally, about 10.72% of soil erosion exports in 2020 was from provinces with lower-than-average SEI, compared to 18.42% in 1990, indicating that current patterns of grain production and consumption are unfavorable for erosion control. Accordingly, measures have been proposed to build a soil erosion control system that includes consumers, such as changing farming practices, optimizing agricultural layout, promoting technology export and establishing a provincial compensation mechanism.