Potential methane emission reduction strategies from rice cultivation systems in Bangladesh: A critical synthesis with global meta-data

Methane (CH4) is one of the dominant greenhouse gases (GHG) that is largely emitted from rice fields and thus, significantly contributes to global warming. Significant efforts have been made to find out suitable strategies to mitigate CH4 emission from rice culture. However, the effectiveness of these management practices is often diverse with negative, no, or positive impacts making it difficult to adopt under a particular condition. The diversity of rice cultivation in terms of agroclimatic conditions and cultivation practices makes it difficult for providing specific recommendations. Here, we collected data from a total of 198 studies reporting 1052 observations. The management practices are categorized into five different management practices i.e., water, organic and inorganic fertilizer management, crop establishment method, and agronomic practices while major categories were subdivided into different classes. To test statistically significant differences in the effectiveness between major management practices, an analysis of variance (ANOVA) was applied. The Gaussian and boot-strapping model were applied to find out the best estimate of the effectiveness of each practice. In addition, mechanisms controlling the CH4 emission reductions were synthesized. Next, the adoption potentials of these practices were assessed based on the existing rice cultivation systems in Bangladesh. Our results showed that water and organic matter management were the most effective methods irrespective of the growing conditions. When these technologies are customized to Bangladesh, water management and crop establishment methods seem most feasible. Among the rice-growing seasons in Bangladesh, there is a larger scope to adopt these management practices in the Boro season (December to May), while these scopes are minimal in the other two seasons due to their rain-fed nature of cultivation. Altogether, our study provides fundamental insights on CH4 reductions strategies from rice fields in Bangladesh.