Mycelial traits and GRSP in enhancing soil stability on cold region highway slopes: Comparative effects of three shrub species

Summary

Researchers studied how three different shrub species stabilize soil on steep highway slopes in cold regions of China. They found that Amorpha fruticosa was most effective at strengthening soil because it develops extensive fungal networks and produces more of a special soil protein called GRSP. Interestingly, steep slopes made the GRSP less effective, so the fungal networks became more important. This research helps engineers and environmental managers choose the best plants to prevent slope erosion and landslides.

Background

Soil aggregate stability is critical for slope ecosystem resilience and infrastructure preservation in cold regions. However, understanding how mycelial traits and glomalin-related soil protein (GRSP) jointly regulate soil stability across varying slope gradients remains limited.

Objective

This study investigated the role of mycelial traits and GRSP fractions in reinforcing soil aggregate stability by examining three shrub species (Amorpha fruticosa, Lespedeza bicolor, and Swida alba) across two slope gradients (30° and 60°) in northeastern China.

Results

Amorpha fruticosa exhibited significantly greater aggregate stability (23.1-36.9% higher at steep slope, 8.7-30.4% higher at gentle slope) than the other species. Strong correlations (r > 0.90) between EE-GRSP, mycelial traits, and aggregate stability explained up to 95.1% variance on gentle slopes. Slope gradient modulated trait efficacy: GRSP contribution diminished on steep slopes, leaving mycelial traits as dominant drivers.

Conclusion

The study reveals a slope-dependent reallocation between physical scaffolding (mycelial traits) and biochemical adhesion (GRSP), with Amorpha fruticosa identified as critical for slope stabilization. Findings provide mechanistic basis for shrub species selection in slope restoration and offer practical insights for erosion control under global change.
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