The Role of Green Manures in Sustaining Soil Fertility and Crop Productivity: A Comprehensive Review

Abstract

Soil degradation driven by intensive monocropping and excessive dependence on synthetic fertilizers has severely compromised soil organic carbon, nutrient balance, and biological activity in major agricultural regions, particularly the Indo-Gangetic Plains. Green manuring has re-emerged as a sustainable strategy to restore soil fertility and enhance crop productivity. It involves the incorporation of fresh green plant biomass into the soil to enhance organic matter content and nutrient availability. Leguminous green manures such as dhaincha (Sesbania aculeata) and sunnhemp (Crotalaria juncea) are widely used because of their ability to fix atmospheric nitrogen and improve soil physical, chemical, and biological properties. Numerous studies conducted across different cropping systems and agro-climatic regions have demonstrated that green manuring enhances soil structure, increases microbial activity, improves nutrient cycling, and reduces dependence on chemical fertilizers. In addition, the practice contributes to sustainable crop production by improving soil resilience and maintaining long-term productivity. This review summarizes recent research findings on the effects of green manuring on soil properties and crop performance under diverse cropping systems. The study highlights the importance of integrating green manures into sustainable nutrient management strategies for environmentally sound agriculture.