Regenerative rice farming for sustaining productivity, reducing energy demand, and methane emissions in India: A comprehensive review

• Annual mean atmospheric concentration of methane in India ranged from 1889 to 2017 ppb in 2020 • Traditional transplanted puddled rice cultivation consumes 1000–2000 mm of water • Regenerative rice saves 45-60% of water (n=16 studies), reduces methane emissions 34-78% (n= 9 studies) and energy consumption 6.4-42.5% (n=9 studies) • Fine-tuning regenerative rice technologies is critical for large-scale promotion to achieve SDG – 2, 12, 13, and 15 Rice is cultivated on approximately 165 million hectares in over 100 countries, serving as a staple food for more than 3 billion people. Asia accounts for ∼90% of global rice production, while rice contributes around 40% of India's food grain production. Traditional rice cultivation relies heavily on water resources (between 1000 and 2000 mm), consumes high labour and energy, and emits substantial methane gases. As estimated, the annual mean atmospheric concentration of methane (CH 4 ) ranged from 1889 to 2017 ppb (2020 annual mean across India), which is critical and demands an alternative, sustainable solution. Thus, the regenerative rice system stands out as a viable option to address these environmental challenges and can contribute to sustainable agricultural development while also reducing energy demands. This method employs direct seeding in non-puddled fields. It creates an aerobic soil environment, promoting strong rice roots and a median water reduction of 52.5% (IQR: 45-60%; n=16 studies), thriving on 600-700 mm. Similarly, based on field experiments, it was revealed that an average energy consumption decrease of 24.5% (IQR: 6.4-42.5%; n = 9 studies) and a reduction in methane emissions by 56% (IQR: 34-78%; n = 9 field studies) were observed. Regenerative rice contributes to Sustainable Development Goals 2 (Zero Hunger), 12 (Responsible Production and Consumption), 13 (Climate Action), and 15 (Life on Land), while reducing environmental impact compared to a puddled rice system. To evaluate its potential for scaling, this review examines existing research on regenerative rice production systems and proposes future research, extension, and policy advocacy directions.