International Journal of Plant & Soil Science

Rice (Oryza sativa L.) feeds roughly half of the world’s population, yet flooded paddies are among the largest agricultural sources of methane, a short-lived but potent greenhouse gas. Carbon farming, understood here as the deliberate management of farmland to reduce greenhouse gas emissions or increase durable carbon storage under rules that allow those outcomes to be quantified and rewarded, has recently been extended from soil carbon in upland systems to methane reduction in rice. This critical narrative review examines whether the evidence base is strong enough to support that extension and how rice-based carbon farming interacts with the Sustainable Development Goals. Peer-reviewed literature and authoritative institutional sources published from January 2000 onwards were identified through multidisciplinary scholarly databases, a regional index, citation chasing and targeted searches of inventory, policy and crediting documents, and were appraised for design, measurement completeness and external validity. The evidence is strongest for water management: field studies and several independent meta-analyses agree that alternate wetting and drying and mid-season drainage reduce methane emissions by roughly half, with small average yield effects when soil drying is mild. Confidence is weaker for the net climate benefit, because nitrous oxide responses, fallow-season emissions and long-term soil carbon losses are measured inconsistently and are rarely captured together. Straw removal from the growing season, low-emission cultivars, direct seeding and optimised nitrogen management show credible but context-dependent effects, whereas biochar and soil carbon gains raise unresolved questions of permanence, scale and verification. Monitoring, reporting and verification remain the principal bottleneck: emission factors, process models and satellite approaches disagree at regional scale, and farm-level verification of water management is costly. Synergies with food security, water productivity and grain arsenic reduction are well documented, but trade-offs involving nitrous oxide, cadmium, wetland biodiversity, unequal access to irrigation control and incentive design are under-studied. Rice carbon farming is therefore best regarded as a promising but conditional mitigation pathway whose credibility depends on full-season, multi-gas accounting, conservative crediting and explicit attention to social and ecological co-impacts.