Potential impact of soil erosion spatial distribution on soil nutrient loss of dryland in the Northeast Plain

Purpose This study delineated the impact of soil erosion on nutrient loss of dryland in the Northeast Plain, aiming to provide a scientific basis for the effective management and rational protection of soil resources in the region. Methodology Utilizing the RUSLE model and GIS technology, this study analyzed the spatial variation characteristics of soil erosion intensity and soil nutrients content (SOC, TN, TP and TK) in the 0-30 cm depth of dryland soil, and clarified the impact of erosion spatial distribution on soil nutrient loss of dryland in the Northeast Plain during 2010-2018. Results (1) Soil erosion was primarily characterized as slight, with the following ranking of erosion intensity: Liaohe Plain>Songnen Plain>Sanjiang Plain. Moderate to severe erosion was mainly distributed in the central, western and southern parts of the Liaohe Plain, the central and southwestern parts of the Songnen Plain, and the central and southern parts of the Sanjiang Plain. (2) The spatial distribution of SOC and TN of dryland in the Northeast Plain increased from southwest to northeast, while TP showed a radially increasing trend from the center to the surroundings and TK exhibited a radially decreasing trend from the center to the surroundings. The content of SOC, TN and TP in the three sub-plains was in the order of Sanjiang Plain>Songnen Plain>Liaohe Plain, whereas the content of TK was in the order of Songnen Plain>Sanjiang Plain>Liaohe Plain. The nutrient content of dryland in the three sub-plains showed a continuous decreasing trend with increasing soil erosion intensity. (3) The soil nutrient loss of dryland in the Northeast Plain showed a pattern of being higher in the west and lower in the east, where the loss in the Liaohe Plain was higher than that in the Songnen Plain and Sanjiang Plain. The total loss of SOC, TN, TP and TK was 2.95×107 t, 3.24×106 t, 1.67×106 t and 6.24×107 t respectively, and the total loss of the four nutrients reached 9.68×107 t. With the intensification of erosion, the average loss per unit area of each nutrient showed a significant increasing trend in the three sub-plains, while the total loss of each nutrient exhibited a trend of initial increase, followed by a decrease, and then a sharp increase. The total loss of each nutrient was the largest in the area of severe erosion, followed by that in the area of slight erosion. In areas with very strong erosion and severe erosion, the total loss of each nutrient was in the order of Liaohe Plain>Songnen Plain>Sanjiang Plain. Conclusion The areas of severe and slight erosions in the three sub-plains, especially the areas of very strong erosion and severe erosion of the Liaohe Plain, should be prioritized for the prevention and control of soil erosion and nutrient loss of dryland in the Northeast Plain.