Crop diversification and water-efficient irrigation: Insights from the TNIAMP initiative in the Cauvery Delta sub-basin

Abstract

The Cauvery Delta, historically known as the "Granary of Peninsular India," is crucial for Tamil Nadu’s agriculture but faces growing challenges from water scarcity, salinity and climate change. The water-intensive rice cultivation in the region needs an alternative crop to minimize the water requirement. This study examines maize as a viable crop under the Tamil Nadu Irrigated Agriculture Modernisation Project (TNIAMP). Maize requires less water, has shorter cultivation cycles and offers higher profitability, achieving an average yield of 5497 kg and a benefit-cost (B:C) ratio of 1.76 for dry seed production. To promote diversification, maize was demonstrated across 5000 ha using improved technologies like nutrient and pest management. Results show fresh cob production is particularly profitable, with a B:C ratio of 2.68 compared to 1.06 for paddy. Diversification indices, including the Herfindahl Index (HI) and Entropy Index (EI), reveal a positive shift toward diversified cropping patterns since 2017 due to maize adoption. These trends mitigate risks associated with monocropping and improve resilience to environmental challenges. Although challenges such as groundwater salinity and erratic water supply persist, targeted interventions such as farmer training, improved irrigation practices and institutional support have facilitated a steady increase in maize cultivation across Thanjavur, Thiruvarur and Nagapattinam districts. The study highlights maize’s potential to address water scarcity while enhancing agricultural sustainability and farmer livelihoods. This research emphasizes the importance of maize in balancing efficiency and diversity in cropping systems, advocating for continued institutional support, adaptive strategies and farmer-centric policies to ensure long-term sustainability. By integrating economic and environmental benefits, this study offers actionable insights for policymakers and stakeholders seeking to mitigate climate challenges and secure agricultural resilience in the Cauvery Delta.