Effects of straw mulching on sediment particle distribution and soil erosion control

Soil erosion poses a global threat to agricultural sustainability, particularly in vulnerable regions such as the sloping croplands of southern China’s red loam region. The study evaluates the efficacy of straw mulching versus conventional tillage (T) in mitigating erosion and regulating sediment sorting during the peanut growing season. Through simulated rainfall experiments using a FULLJET nozzle simulator (intensity: 90 mm/h; duration: 90 min; uniformity >0.85) in controlled soil troughs (2 m × 1 m, 10° slope), straw mulching delayed runoff initiation by 0.14–4.63 min, reduced total runoff by 5.69–12.02 times, and decreased sediment yield by 5.58–18.87 times compared to T. These benefits were most pronounced during the sowing and emergence stages, where straw mulching enhanced surface roughness and soil infiltration, curbing early-stage erosion. Sediment under straw mulching shifted to silt-dominated compositions (51–97 %), with agglomerated particles reducing coarse particle loss (>0.05 mm) by 40–60 %. straw mulching also altered sediment transport dynamics, increasing fine particle enrichment while stabilizing soil structure. These findings demonstrate that straw mulching not only effectively controls erosion but also optimizes sediment sorting, offering a practical strategy to safeguard soil productivity and water quality in vulnerable agroecosystems. The study underscores the viability of straw mulching as a low-cost, scalable solution for smallholder farmers, aligning ecological benefits with sustainable land management goals.