The role of legume roots in carbon sequestration, soil health enhancement, and salinity mitigation under climate change: A comprehensive review

Legumes play a crucial role in sustainable agriculture by enhancing soil health, nitrogen cycling, carbon sequestration, and salinity mitigation, particularly in the face of climate change. This review synthesizes current knowledge on how legume roots and associated microbial interactions contribute to these processes. The deep-rooting systems of legumes stabilize soil structure while increasing soil organic carbon (SOC) fractions by up to 29.6 %. Through biological nitrogen fixation (BNF), legumes reduce reliance on synthetic fertilizers by up to 40 %, improving soil fertility and resilience. Additionally, legume cropping systems promote beneficial rhizobacterial communities, enhancing microbial nitrogen transformations. Meta-analyses reveal that intercropping legumes with non-legumes can significantly improve soil nutrient availability, microbial biomass, and overall crop yield while mitigating nitrogen losses. Furthermore, certain legume species thrive in saline soils, reducing soil salinity by up to 9.6 % and improving structure via organic matter accumulation and root-microbe interactions. Case studies across various agroecosystems highlight the real-world applications of legume-based strategies, showing measurable improvements in soil carbon storage, nitrogen cycling efficiency, and salinity reduction. These findings underscore the importance of site-specific legume management practices to maximize benefits under diverse environmental conditions. Future research should refine legume species selection, intercropping strategies, and biochar applications to enhance soil resilience and sustainability in a changing climate. This review provides a data-driven understanding of the multifaceted roles of legumes, offering insights into their potential as key components of climate-smart agriculture.