Dual cropping in rice: Integrating Azolla, dhaincha and legumes for sustainable rice production

Rice production systems are under increasing pressure to enhance productivity while conserving natural resources and maintaining long-term soil fertility. Dual cropping has emerged as a promising strategy for improving the sustainability of rice production through the integration of compatible companion crops. Common companion crops include Azolla, dhaincha (Sesbania spp.) and grain legumes. These systems improve the use efficiency of land, water and nutrients while reducing dependence on synthetic fertilisers. This review synthesises current knowledge on rice-based dual cropping systems, focusing on their ecological basis, agronomic performance and environmental benefits. The review analyses the impact of weather conditions, soil fertility, water use and cropping calendar on the efficient introduction of dual cropping systems. The advantages of such systems in enhancing nutrient recycling, soil health, soil microbial activity, weed and pest control and resource use efficiency are also discussed. Furthermore, the economic benefits, advancements in technology, existing limitations and potential research areas in rice + Azolla, rice + dhaincha and rice + legume systems are discussed. Evidence from recent studies shows that well-managed dual cropping systems improve crop productivity, enhance soil quality, reduce production costs and strengthen the sustainability of rice cultivation. Future research should focus on optimising crop combinations and planting schedules, precision nutrient and water management, long-term soil-health assessment and integration of remote sensing, internet of things (IoT), artificial intelligence (AI) and decision-support systems. Supportive policies, farmer training and improved access to quality planting material are also recommended to promote wider adoption.