Variation characteristics of soil nutrients in erosion gully of slope farmland with different management years

Objective Due to the combined effects of human activities and natural factors, soil erosion in the black soil region has intensified, with gully erosion being the most severe. Gully erosion not only leads to the loss of black soil resources and reduced crop yields but also triggers the decline of soil ecological functions, posing a threat to national food security and ecological balance. Methods To investigate the patterns of soil nutrient changes in eroded gullies on sloping farmland with different management durations, this study selected erosion gullies treated for 2 years and 7 years as research subjects, with developed gullies serving as controls. Soil samples were collected from both the gully slopes and bottoms using the diagonal sampling method, and soil nutrients were measured. Correlation analysis and principal component analysis were applied to elucidate the patterns of soil nutrient changes in the 2-year and 7-year treated erosion gullies. Results 1) Results indicate that compared to the undeveloped gully, both the 2-year and 7-year managed erosion gullies showed significantly higher levels of soil organic matter, total nitrogen, alkali-hydrolyzable nitrogen, total phosphorus, available phosphorus, total potassium, and available potassium (P＜0.05). 2) There was a significant positive correlation between the nutrient indexes, and the correlation coefficient increased with the extension of the treatment years. 3) The comprehensive evaluation scores from principal component analysis were: 7-year managed gully (2.303) > 2-year managed gully (1.747) > undeveloped gully (0.873). This indicated that the extension of treatment years significantly improved the overall recovery level of soil nutrients.Conclusion The increase of treatment years has positive significance for soil fertility restoration of slope farmland erosion ditch in the black soil region of Northeast China, this study can provide solid data support and scientific decision-making basis for accurate management and ecological restoration of erosion gullies in black soil region.