Conservation agriculture for climate-resilient agri-food systems: Enhancing productivity, profitability, and sustainability

Soil degradation, declining resource-use efficiency, and increasing climate variability are major challenges to agri-food security and the sustainability of cereal-based cropping systems in South Asia. Conventional rice–wheat (R-W) systems in the Eastern Indo-Gangetic Plains (EIGP) of India are highly input-intensive, environmentally fragile, and nutritionally limited, making them vulnerable to climate-induced stresses. This study evaluates the potential of conservation agriculture (CA) interventions-namely zero tillage, direct-seeded rice, timely sowing, and legume integration to enhance productivity, profitability, resource-use efficiency, and overall sustainability of the rice ( Oryza sativa L.)–wheat ( Triticum aestivum L.)–mung bean ( Vigna radiata (L.) Wilczek) production system across diverse agro-climatic zones (ACZs) of Bihar, India. From 2019 to 2022, large-scale on-farm demonstrations (44,476) were conducted across 38 project hubs representing four ACZs. System productivity across zones averaged 9.19–9.88 t ha -1 , with the highest mean in Zone-IIIb, (9.88 t ha -1 ) followed by Zone-IIIa (9.81 ha -1 ), compared to Zone-I (9.48 ha -1 ) and Zone-II (9.19 ha -1 ). System profitability showed parallel trends, with mean values of $1,584 ha -1 (Zone-I) to $1,723 ha -1 (Zone-IIIa). Maximum profitability peaked at $2,490.65 ha -1 in Zone-IIIb, while the lowest return ($768.19 ha -1 ) was recorded in Zone-I, reflecting substantial economic gains in favorable zones. The highest nitrogen, phosphorus, and potassium use efficiencies (37.28, 58.12, and 94.09 kg grain per kg nutrient, respectively) and water-use efficiency (0.470 kg ha -1 mm -1 ) were observed in agro-climatic zone IIIb. Protein yield peaked in agro-climatic zone IIIa, while zone IIIb achieved the highest economic sustainability index (0.875) and yield sustainability index (0.944).CA practices consistently enhanced resource-use efficiency, profitability, and sustainability across all ACZs, showcasing their effectiveness under variable environmental conditions. The integration of conservation tillage, timely planting, and legumes offers a scalable approach to sustainable intensification in cereal-based systems. These findings highlight the potential of CA as a climate-resilient strategy to address soil degradation, enhance agri-food security, and improve farm profitability in vulnerable regions. • 44,476 on-farm demos conducted in rice–wheat–mung bean across Bihar (2019–2022). • System yield averaged 9.61 t ha -1 , ranging 6.4–12.2 t ha -1 across ACZs. • Net returns ranged $1539–$1729 ha -1 , highest in ACZ-IIIb, lowest in ACZ-I. • Nutrient-use efficiency peaked in ACZ-IIIb: N=37.28, P=58.12, K=94.09 kg grain/kg. • Sustainability indices highest in ACZ-IIIb: YSI 0.944, ESI 0.875.