Reducing methane emission from rainfed rice fields through utilizing amphibian rice cultivars

Rainfed rice (Oryza sativa L.) fields are the largest rice contributor after irrigated rice fields in Indonesia. As land is vulnerable to climate change impacts, optimizing the productivity of rainfed lowland rice is carried out, among other things, by utilizing superior amphibian rice cultivars. On the other hand, rainfed rice fields whose irrigation depends on rainfall are seen as a source of greenhouse gas emissions, especially methane. The research objective was to determine methane emissions from rainfed rice fields by using amphibian rice cultivars. The field research was conducted in a randomized block design with seven amphibian rice cultivars and the lowland 'Ciherang' as control. The changes measured included plant growth, grain yield, methane flux, and greenhouse gas intensity (GHGI). The tested amphibian rice cultivars emitted methane lower by 2.2%-35.3% than 'Ciherang'. 'Inpari 34', 'Inpari 39', and 'Inpari 42' gave significantly lower GHGI values than other cultivars tested in rainfed rice fields, namely lower by 23.2%-31.5%, 8.1%-18.0%, 14.1%-23.4%, respectively. 'Inpari 34' is an amphibian cultivar that emits the lowest methane and releases the lowest CO2 per ton of grain produced. The cultivars of 'Inpari 34', 'Inpari 39', and 'Inpari 42' are considered suitable and adaptive for rainfed rice fields.