Identifying agronomic practices with higher yield and lower global warming potential in rice paddies: a global meta-analysis

Rice agriculture faces the dual challenge of increasing grain production while reducing global warming potential (GWP). Yield-scaled GWP, a commonly employed indicator, is not sufficient to identify smart agronomic practices that can address this dual challenge. Thus, practices that can increase yield while simultaneously reducing GWP in rice paddies have not yet been clearly defined. In this study, we synthesised independent experiments by meta-analyses to identify agronomic management practices with higher rice yield and lower GWP. The results showed that the application of nitrification inhibitors (NI) and biochar significantly increased rice yield by an average of 9.5% and 9.1%, and simultaneously reduced GWP by 24% and 14%, respectively. Overall, controlledrelease nitrogen (N) fertilisers did not affect GWP despite increasing rice yield (+9.2%). In contrast, conventional N application enhanced both rice yield (+44%) and GWP (+27%). No-tillage reduced GWP (-23%) but did not significantly affect rice yield. Non-continuous flooding in rice paddies significantly reduced GWP (-48%) but also reduced the yield (-4.2%). The rice yield and GWP outcomes were similar for rice-animal co-culture and rice monoculture systems. In conclusion, both NI and biochar application are promising practices for increasing yield while simultaneously reducing GWP in rice paddies. In addition, we suggest that individual agronomic practices should be combined to increase rice yield while mitigating climate warming.

Automated summary

The study shows that the application of nitrification inhibitors and biochar in rice paddies can significantly increase yield and reduce global warming potential. Controlled-release nitrogen fertilisers have no effect on global warming potential, but can increase rice yield. No-tillage and non-continuous flooding can reduce global warming potential, but have different impacts on rice yield.