Meta-analysis of yield-emission trade off in direct seeded vs. puddled transplanted rice: towards a cleaner and sustainable production

Reddy, K. S.; Parihar, C. M.; Panneerselvam, P.; Sarkar, A.; Patra, K.; Bharadwaj, S.; Sena, Dipaka R.; Reddy, S.; Sinha, A.; Dhakar, R.; Kumar, V.; Nayak, H. S. 2025. Meta-analysis of yield-emission trade off in direct seeded vs. puddled transplanted rice: towards a cleaner and sustainable production. Cleaner Environmental Systems, 16:100238. (Online first) [doi: https://doi.org/10.1016/j.cesys.2024.100238]

Conventional rice production through puddled transplanted rice-PTR is tillage, water, energy, and capital intensive. Furthermore, it is a major contributor to greenhouse gas (GHG) emissions. In this regard, Direct seeded rice-DSR can be a potential alternative to PTR. DSR can reduce input use and GHGs emissions, while sustaining yields. However, depending upon agroclimatic situation, DSR impact analysis on GHGs emission and yield resulted inconsistent findings, questioning whether it is better over PTR or not. To bridge this knowledge gap, we performed a meta-analysis synthesizing 876 paired measurements from 54-peer-reviewed studies to understand how DSR impacts N2O and CH4 emissions, GWP (heat-trapping potential of greenhouse gases compared to CO2), yield and C-footprint-CFP (environmental impact in CO2 eq. due to concerned activity). Compared to PTR, DSR decreased CH4 emissions by 70%, GWP by 37% and CFP by 34%, despite 85% increase in N2O emissions. However, this shift comes with a trade-off, with 11% decrease in yield. To decipher the primary factors driving these outcomes, we conducted subgroup analyses by taking assorted environmental conditions and management practices as moderators. Low to medium pH soils, zero tillage, puddled soil (wet DSR), conventional flooding, and high nitrogen rates (>200kg/ha) are found to be favourable for DSR with comparable yields but posing a discrepancy with environmental sustainability. Therefore, further research to evaluate DSR across agro-ecologies, management practices, are needed, to optimize yields with lower GWP and CFP.