Greenhouse Gas Emissions in Rice Cultivation

Rice paddies are among the largest anthropogenic sources of methane (CH₄) and a growing contributor to nitrous oxide (N₂O) emissions. Flooded soils create anaerobic conditions that favour methanogenesis, while intermittent drying and fertiliser application can stimulate nitrification and denitrification pathways producing N₂O. Emissions depend on soil type, water regime, organic amendments and rice genotype. Plant‐mediated transport via aerenchyma channels can enhance CH₄ release, whereas alternate wetting and drying and ground cover systems can shift redox conditions to curb CH₄ and modulate N₂O fluxes. Emerging mitigation strategies span genetic approaches that reallocate photosynthate, agronomic practices that optimise irrigation and mulching, and engineered solutions that oxygenate the rhizosphere. Given rice’s central role in global food security, integrating these approaches is key to reducing its climate impact without compromising yield.

Research from Nature Portfolio

Recent studies have demonstrated the potential of genetic improvement to tackle methane emissions at source. A loss-of-function allele in a key grain‐size gene was shown to divert carbohydrates from roots to grains, reducing methanogen activity in the rhizosphere and cutting CH₄ emissions while boosting yield. Complementary work on ground cover rice production systems has established that replacing continuous flooding with mulched soil cover and biodegradable plastic films can cut CH₄ and N₂O emissions by over half, enhance water‐use efficiency and maintain or improve grain production. These advances illustrate how targeted genetic and material innovations can achieve dual goals of climate mitigation and food security.

Greenhouse Gas Emissions in Rice Cultivation publication trend

The graph below shows the total number of articles in greenhouse gas emissions in rice cultivation across all publications each year (not limited to Nature Index journals).

Technical terms

Methanogenesis: Microbial production of methane under anaerobic conditions in flooded soils.

Aerenchyma: Plant tissue with interconnected air spaces facilitating gas transport between shoots and roots.

Alternate wetting and drying (AWD): Irrigation regime that periodically drains paddies to introduce aerobic phases and reduce CH₄ emissions.

Ground cover rice production system (GCRPS): Technique using mulch or film to cover soil, conserving water and altering greenhouse gas fluxes.

Global warming potential (GWP): Metric comparing the heat‐trapping effect of different greenhouse gases over a given time horizon relative to CO₂.

References

1. Loss-of-function gs3 allele decreases methane emissions and increases grain yield in rice. Nature Climate Change (2023).
2. Reduce methane emission from rice paddies by man-made aerenchymatous tissues. Carbon Research (2023).
3. Methane and nitrous oxide emissions from conventional and modified rice cultivation systems in South India. Agriculture Ecosystems & Environment (2018).
4. Methane transport and emissions from soil as affected by water table and vascular plants. BMC Ecology and Evolution (2013).
5. Improving rice production sustainability by reducing water demand and greenhouse gas emissions with biodegradable films. Scientific Reports (2017).
6. Contribution of rice variety renewal and agronomic innovations to yield improvement and greenhouse gas mitigation in China. Environmental Research Letters (2019).