Background The plentiful and coarse sediment area of the middle Yellow River is the main source of sediment, and the annual average sediment transport load is 1.182 billion tons, accounting for 73.9% of the total sediment flow into the Yellow River. Soil erosion in this area is very serious and the ecological environment is fragile, causing heavy ecological pressure, which not only threatens the local ecological security, but also has a great impact on the downstream river, posing a serious threat to human production and life.
Methods In order to quantify the potential probability of regional soil erosion and identify the key factors of soil erosion, revised universal soil loss equation (RUSLE) and ArcGIS technology were applied in this study to comprehensively evaluate the sensitivity of soil erosion. The key sensitivity factors were also identified by superposition ranking analysis (2010, 2015, and 2020). Visualization of the spatial and temporal distribution of soil erosion sensitivity and key sensitivity factors was achieved.
Results 1) Soil erosion sensitivity showed a decreasing trend from southeast to northwest. The extremely sensitive and highly sensitive areas were mainly found in the central and eastern parts of the study area, while moderate sensitive areas showed a large staggered distribution. 2) From 2010 to 2020, the overall soil erosion sensitivity increased first and then decreased. The west of the study area showed relatively stable low sensitivity, the south, north and some eastern regions of the study area showed a relatively obvious decline, mainly due to the increase of insensitive (6.0%), and the southeast and other eastern areas of the study area increased, mainly due to the expansion of highly sensitive and extremely sensitive areas (1.2%). 3) C factor mainly had a great influence in insensitive areas; K factor controlled most of the central and eastern regions of the study area with the grade higher than slightly sensitive. In the western part of the study area, the combination of R and C factor increased the risk of soil erosion in the area with insufficient vegetation cover, and in the eastern part, the combination of R and K factor had a greater impact on the area with serious soil damage. The LS factor had minor effect on soil erosion in the whole study area.
Conclusions In summary, soil erosion sensitivity in plentiful and coarse sediment area of the middle Yellow River decreased overall, while soil erosion sensitivity in the central and eastern parts was higher, which was mainly affected by K and R factors. The research results provided theoretical guidance for the delineation of key soil erosion protection zones, meanwhile providing support for the targeted management of regional soil erosion.
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