Background In Northeast China's black soil region, prolonged traditional farming coupled with multiple erosive forces, hydraulic, wind, and freeze-thaw, has intensified sloping farmland erosion, resulting in thinning and degradation of the fertile black soil layer. To address this challenge, establishing a conservation system focused on “prevention first and integrated utilization” is essential. Cover cropping has emerged as a promising strategy to improve soil structure and erosion resistance. This study explores how intercropping maize (Zea mays) with cover crops affects soil erosion resistance, aiming to identify optimal crop combinations and planting patterns for sustainable black soil management.

Methods A field experiment was conducted on a typical black soil slope cropland in northeastern China with five treatments: 1) bare land as CK; 2) maize monoculture Y; 3) maize–white clover (Z. mays–Trifolium repens) Y_+B; 4) maize–ryegrass (Z. mays–Lolium perenne); Y_+H; and 5) maize–white clover–ryegrass (Z. mays–T. repens–L. perenne) Y_+B+H. The erosion resistance of the soils was systematically assessed by three complementary methods: the wet sieve method for analyzing aggregate stability, the flume test for measuring scour resistance and the direct shear test for quantifying shear strength. In addition, a comprehensive assessment framework was developed using principal component analysis (PCA), integrating 12 key soil quality indicators was used for comprehensive evaluation and pattern selection.

Results 1) Intercropping maize with cover crops significantly improved the physical properties of the soil. Maize + white clover + ryegrass treatment was the most effective, increasing total soil porosity by 14.39% and water-holding capacity by 6.4% compared to bare land (CK). 2) Corn + white clover intercropping achieved the highest aggregate stability in both 0 − 10 cm and 10 − 20 cm soil layers, with aggregate crushing rates of 22.26% and 17.18% respectively, significantly lower than those in other treatments. 3) Surface soil (0 − 10 cm) erosion resistance improved markedly, with scouring resistance coefficients reaching 61.93 L/g (maize + ryegrass) and 50.86 L/g (maize + white clover & ryegrass), representing 96.5% and 95.7% increases over bare land. 4) The maize + white clover & ryegrass system also demonstrated superior shear strength, with a 5.4° internal friction angle and 15.4 kPa cohesion, 25.5% and 13.5% higher than CK. 5) Overall erosion resistance ranked as: Maize + white clover + ryegrass > maize + ryegrass > maize monoculture > bare soil > maize + white clover.

Conclusions Intercropping maize with cover crops, especially the combination of white clover and ryegrass, substantially enhances soil erosion resistance on sloping black soil. These findings provide a scientific basis for cover crop selection and configuration, offering valuable guidance for the sustainable utilization and conservation of black soil resources.