Human activities are the key driver of water erosion changes in northeastern China

Abstract

Northeast China is experiencing severe soil erosion, resulting in land degradation and nutrient loss. Among them, water erosion poses the greatest threat to food security. Combining various multi‐source data, we applied the modified soil erosion equation (RUSLE) to evaluate the water erosion modulus in Northeast China (1985–2021). We used the threshold segmentation and residual analysis method to quantify the relative roles of climate change and human activities on water erosion. The outcomes were as follows: (1) In recent decades, the average annual water erosion modulus in northeastern China was 804.78 t·km−2·a−1, decreasing with a slope of −11.114 t·km−2·a−1. In 24% of the study area, the erosion modulus increased significantly, mainly in grassland and farmland, due to grassland degradation and expansion of sloping cropland. In 20% of the study area, erosion modulus decreased significantly, mainly spread in forests, which was attributed to the implementation of important ecological restoration projects by the Chinese government, such as afforestation programs and returning farmland to forest. (2) During the research process, there were spatial variations in water erosion drivers in Northeast China. For areas with significant increases in erosion, 20% of the total study area were caused by anthropogenic factors, and 3% were attributed to natural factors. For areas where erosion had significantly improved, 18% of the total study area was attributed to ecological restoration, and 2% to natural factors. (3) Based on the results of the study, ecological restoration of forests and grasses, management of sloping cropland, and conservation tillage were recommended to reduce soil erosion in Northeast China.

Impacts of Crop Type and Climate Changes on Agricultural Water Dynamics in Northeast China from 2000 to 2020

“…Farmers tend to cultivate and increase the area of highly waterintensive maize and rice in order to increase their returns, which mainly because of the two crops have higher yields and economic benefits than soybean [37]. However, the expansion has led to an increase in the agricultural water requirement, a decline in the groundwater levels, reduction in soil organic matter, and degradation of black soil, which is not conducive to sustainable agriculture development [57][58][59][60][61]. Thus, we should curb the massive expansion of water-intensive crops and encourage an increase in the area of soybean that is water-saving and soil-beneficial.…”