The role of alfalfa (Medicago sativa L.) in soil health and greenhouse gas mitigation in integrated crop-livestock systems: a review

Abstract

Alfalfa (Medicago sativa L.) is a multifunctional perennial forage legume that delivers significant agronomic, nutritional, and ecological benefits within integrated crop–livestock systems. Its deep taproot enhances drought tolerance, soil water capture, and nutrient cycling, while high biomass production (up to 20 t ha⁻¹ yr⁻¹) and crude protein content (15–25%) improve livestock productivity, including milk yield and growth. Alfalfa also supports soil health through symbiotic nitrogen fixation (0.10–0.30 t N ha⁻¹ yr⁻¹), organic matter accumulation, and carbon sequestration (1.2–5 t C ha⁻¹ yr⁻¹), reducing reliance on synthetic fertilizers by 30–70% and lowering nitrous oxide emissions by up to 50%. Its adaptability across semi-arid, temperate, and tropical environments, combined with climate-smart management, contributes to resilient and low-emission production systems. However, challenges such as pest and disease pressure, salinity stress, establishment difficulties, and limited adoption in resource-constrained regions persist. This review highlights the need for stress-tolerant cultivars, optimized rotations, and targeted extension services to fully harness alfalfa’s role in sustainable livestock production and climate-change mitigation.