Legumes impacts and interactions with soil erosion

Soil erosion is a major challenge for agroecosystem sustainability, especially when intense rainfall events correspond to limited soil cover. This review examines how herbaceous legumes influence erosion-related processes, focusing on affecting the cover-management factor (C) and K-factor related soil properties within RUSLE framework. Legume effect on soil erosion was affected by soil conditions, climate, species traits, management, phenological stage, and the reference system. Overall, legume-based systems performed better than bare soil and sole-crop systems in mitigating runoff and soil loss. Runoff reduction ranged from 8 to 75%; while soil or sediment loss decreased from 13 to 92% depending on the reference treatment and management context, including bare soil or sole crops, no-tillage with full-surface cover, legume strips, legume-grass mixtures, and crop phenological stages. C factor for legume (dried pulses and protein crops) is 0.32 in standard conditions but ranged from 0.21 to 0.23 for pure legumes covers, down to 0.015 in legume-grass mixes. Legumes also affected K-related properties by improving aggregation, root cohesion, pore structure, and infiltration, although direct K-factor changes were rarely quantified. Infiltration often improved relative to bare soil or fallow, although comparisons between legumes and grasses remained strongly context-dependent. Grasses and cereal cover usually offered faster canopy closure, greater biomass, and more persistent residues, whereas legumes contributed mainly through nitrogen inputs, residue quality, rhizosphere activity, root-channel formation and longer-term soil structure changes. Legumes can support erosion-control strategies; however, their most reliable contribution occurs in diversified systems, legume-grass mixes, and conservation practices maintaining continuous soil cover during erosive periods.