Objective In the black soil region of Northeast China, the soil surface remains bare for a relatively long period after harvest and before snowfall, as well as after snowmelt and before seedling emergence, leading to a high erosion risk. In particular, snowmelt erosion intensifies soil and water loss and soil quality degradation in this region. Therefore, it is urgent to explore effective cover measures during the fallow period and evaluate their effectiveness.

Methods Using Zea mays monoculture as the control, five winter cover crop treatments were established: Triticum aestivum, Agropyron cristatum, Medicago sativa, Vicia villosa, and Medicago sativa-Vicia villosa mixture. Soil basic physicochemical properties, aggregate stability, soil anti-erodibility, and soil anti-scourability were systematically measured, and the entropy weight–fuzzy comprehensive evaluation method was applied for comparative analysis.

Results 1) T. aestivum significantly reduced soil bulk density and increased soil total porosity. M. sativa significantly increased soil organic matter content (4.36 g/kg higher than that of Z. mays), and the M. sativa-V. villosa mixture significantly increased soil total nitrogen content (0.23 g/kg higher than that of Z. mays). 2) A. cristatum significantly increased the proportion of soil macroaggregates ( > 0.250 mm) and mean weight diameter, showing the highest aggregate stability. 3) The anti-erodibility indices of T. aestivum and M. sativa-V. villosa mixture were 35% and 45% higher than that of Z. mays, respectively. M. sativa had the highest anti-scourability index, which was 5.5 times that of the control. 4) The comprehensive evaluation indicated that the order of winter cover crops in improving black soil erosion resistance was: M. sativa-V. villosa mixture > A. cristatum > V. villosa > T. aestivum > M. sativa > Z. mays.

Conclusions Planting winter cover crops after Z. mays harvest significantly improves the physicochemical properties and structure of black soils, thereby enhancing soil erosion resistance. The effects vary among different cover crops. Among them, the legume (M. sativa)-legume (V. villosa) mixture performs best, demonstrating its potential for application during the fallow period in the black soil region of Northeast China. The findings provide a scientific basis for erosion control on sloping farmland and sustainable utilization of black soil resources.