降雨特征和耕作措施对云南高原红壤缓坡地产流产沙及粒径分级的影响

李金红; 赵新梅; 王炽; 陈安强; 胡万里; 陈兴位; 闫辉; 付斌; 倪明; 李枝武

doi:10.16843/j.sswc.2026152

降雨特征和耕作措施对云南高原红壤缓坡地产流产沙及粒径分级的影响

Effects of rainfall characteristics and tillage practices on runoff, sediment yield, and particle size distribution on red-soil gentle slopes of Yunnan Plateau

摘要

摘要:
目的明确降雨特征和耕作措施对红壤缓坡地水土流失及侵蚀泥沙粒径分选的作用，为云南高原红壤缓坡地优化耕作措施、水土流失防控提供参考。
方法以滇中典型缓坡地为研究对象，设置5种处理：顺坡耕作（CK）、横坡耕作（T1）、顺坡+横坡（T2）、顺坡+植物篱（T3）和顺坡+大豆间作（T4）。降雨特征有4种：Ⅰ类中历时中雨型降雨；Ⅱ类中长历时大暴雨型降雨；Ⅲ类长历时小雨型降雨；Ⅳ类短历时大雨型降雨，探究降雨特征与耕作措施对坡面侵蚀及泥沙粒径分级的影响。
结果 1）Ⅱ类降雨引发的径流深（1.38 mm）和泥沙量（2.39 g/m²）最大；Ⅳ类降雨产沙量较低，但侵蚀泥沙0.25～ 2 mm粒径比例最高（46.19%）。2）与CK相比， T1-T4处理平均减少径流深33.47%、泥沙量49.50%；其中T1处理减流效果最佳（43.98%）；T3处理减沙效果最好（72.25%），中值粒径（D₅₀）降低49.00%，0.002～0.05 mm和 < 0.002 mm粒径分别增加35.19%和95.78%。3）最大60min降雨强度（I₆₀）是驱动侵蚀泥沙粒径分级的最关键因子，解释度为48.70%。
结论横坡耕作减流效果最佳，植物篱减沙效果最优，推荐二者作为红壤缓坡地水土保持措施，同时区域防治水土流失应重点关注Ⅱ类降雨的侵蚀风险，并将I₆₀作为预警的关键指标。研究结果可为云南高原缓坡地水土流失的精准阻控提供科学依据。

Abstract:
Objective This study aims to elucidate the effects of rainfall characteristics and tillage practices on soil erosion and eroded sediment particle size distribution on red-soil gentle slopes, thereby providing a reference for optimizing tillage practices and controlling soil erosion on red-soil gentle slopes of the Yunnan Plateau.
Methods Typical gentle slopes in central Yunnan were selected as the research objects, with five tillage treatments established: downslope tillage (CK), contour tillage (T1), downslope + contour tillage (T2), downslope + hedgerow (T3), and downslope + soybean intercropping (T4). Four types of rainfall events were identified: Type I—moderate-duration moderate-intensity rainfall; Type Ⅱ—medium-to-long-duration heavy rainstorm; Type Ⅲ—long-duration light rainfall; and Type Ⅳ—short-duration heavy rainfall. The effects of rainfall characteristics and tillage practices on slope erosion and sediment particle size distribution were investigated.
Results 1) Type Ⅱ rainfall generated the largest runoff depth (1.38 mm) and sediment yield (2.39 g/m²), whereas Type Ⅳ rainfall produced relatively low sediment yield but had the highest proportion of eroded sediment in the 0.25–2 mm particle size fraction (46.19%). 2) Compared with CK, treatments T1–T4 reduced runoff depth by an average of 33.47% and sediment yield by 49.50%. Among them, T1 achieved the best runoff reduction (43.98%), while T3 showed the greatest sediment reduction (72.25%), accompanied by a 49.00% decrease in median particle size (D₅₀) and increases of 35.19% and 95.78% in the 0.002–0.05 mm and < 0.002 mm particle size fractions, respectively. 3) The maximum 60-min rainfall intensity (I₆₀) was the most critical factor driving eroded sediment particle size distribution, with an explanatory power of 48.70%.
Conclusions T1 is most effective in reducing runoff, while T3 performs best in reducing sediment yield, and both are recommended as effective soil and water conservation measures for red-soil gentle slopes. Regional soil erosion control should prioritize the erosion risk associated with Type Ⅱ rainfall, and I₆₀ is recommended as a key early warning indicator. These findings provide a preliminary scientific basis for the targeted prevention and control of soil erosion on red-soil gentle slopes of the Yunnan Plateau.

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