Carbon sequestration and greenhouse gas emissions for different rice cultivation practices

Traditional rice farming systems require large amounts of water for irrigation, labour for transplanting culms and tending fields, and therefore, emit large amounts of greenhouse gases such as carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4). Adopting alternative rice farming practices could reduce greenhouse gas emissions and increase carbon (C) sequestration. In this study, an on-site field experiment was conducted to assess the contribution of carbon by farm operations involved in the three types of rice cultivation practices: conventional (CVN), the system of rice intensification (SRI), and zero-tillage (ZTL). The study was aimed to examine the carbon indices under three different rice cultivation methods to assess the ecosystem services and disservices associated with carbon sequestration and emission. Results showed that fertilizer application significantly contributed to GWP among the three cultivations. In the CVN and ZTL plots, the GWP was higher for CH4 and N2O. However, all three cultivation strategies acted as carbon sinks, with SRI cultivation yielding the highest sequestration values. The lower CF, higher CS, and higher CER values were obtained for SRI field plots than the other two cultivation practices. The ratio between ecosystem services and disservices in terms of US$ was highest for SRI, followed by ZTL and CVN cultivations. In summary, sustainable agriculture could promote by applying organic manure in the context of SRI cultivation in the water-scarce zones and ZTL cultivation in the tropical upland zones, where such cultivation is not yet practised. Not only will this increase net carbon sequestration, but it will also benefit farmers soon in terms of yield.