Energy dynamics of rice cultivation: Comparative analysis of establishment methods for sustainable production

Rice (Oryza sativa L.) is a staple crop critical for food and nutritional security in India, but its cultivation under traditional puddled transplanted rice is highly resource-intensive, demanding excess water, labour and energy. With growing concerns about groundwater depletion, energy scarcity and rising production costs, resource-efficient alternatives such as dry direct-seeded rice (DDSR) and wet direct-seeded rice (WDSR), coupled with improved irrigation regimes, are gaining importance. The present field investigation was conducted during the kharif seasons of 2021 and 2022 at the Agricultural Research Station, Kampasagar, Telangana, to evaluate the energetics of rice under three establishment methods and three irrigation regimes [conventional submergence, saturation and alternate wetting and drying irrigation (AWDI)]. Results revealed significant differences among establishment methods for specific energy, energy productivity and energy efficiency ratio, whereas irrigation regimes showed non-significant effects. Among the establishment methods, WDSR recorded the lowest specific energy requirement (5.8 MJ kg-1), the highest energy productivity (0.18 kg MJ-1) and superior energy efficiency ratio (2.6), thereby outperforming transplanted rice (TPR) and DDSR. This advantage is particularly relevant under conditions of groundwater depletion and rising energy costs, as rice alone accounts for nearly 50–60 % of irrigation water withdrawals in India, while groundwater pumping contributes about 25 % of total farm energy costs. Across irrigation regimes, AWDI lowered specific energy by ~7–8 % compared to conventional submerged (CS) (5.9 vs. 6.4 MJ kg-1) and improved energy productivity by ~6–12 % (0.17–0.18 vs. 0.16–0.17 kg MJ-1), with efficiency ratio gains of ~4–9 % (2.4–2.6 vs. 2.3–2.4), although differences were statistically non-significant. Overall, WDSR combined with AWDI emerged as the most energy-efficient approach, ensuring sustainable resource utilization without compromising yield. Energetics evaluation thus highlights the potential of alternative establishment methods and water-saving irrigation practices to enhance energy-use efficiency, supporting eco-friendly and economically viable rice cultivation in semi-arid canal command regions.