Approaches for Fertility Management in Legume-based Cropping Systems: A Review

Abstract

Grain and forage legumes occupy a special agronomic position through symbiotic biological nitrogen fixation (BNF) and favourable residual effects on soil fertility, yet legume-specific nutrient- and soil-fertility management is often addressed piecemeal rather than as an integrated system. This review synthesises agronomic and soil-fertility knowledge on legume-based systems, including BNF and rhizobia-legume symbiosis, cereal-legume intercropping and rotation, integrated and site-specific nutrient management, biofertilizer and PGPR technologies, organic amendments and residue management, soil organic carbon dynamics and precision nutrient management through digital tools, for the major pulse and oilseed-legume crops of India. Legumes vary widely in their capacity to supply soil nitrogen, typically deriving 60-70% of it from atmospheric sources and contributing 15-125 kg N/ha/season, depending on rhizobial compatibility, soil nitrate status and moisture. Intercropping with cereals generally raised system productivity by about 30-35%, while balanced P, S and micronutrient application, compatible microbial inoculation and integrated nutrient management sustained productivity while cutting chemical fertiliser dependence by up to 25%. These responses are agro-ecologically dependent rather than universal; priority research areas include site-specific nutrient calibration, inoculant-soil compatibility, quantification of residue effects on subsequent crops and digital decision-support tools for legumes. Wider adoption of legume-centred, integrated soil-fertility management, supported by precision-agriculture tools, offers a practical means toward more resilient, input-efficient and environmentally friendly cropping systems, especially for rainfed smallholder agriculture.