An Giang province is one of the key agricultural areas of the Mekong Delta, where intensified rice cultivation has resulted in large quantities of rice straw that are predominantly disposed of through open-field burning, significantly contributing to atmospheric CO₂ emissions. This study examines the current status of rice cultivation and rice straw management practices, quantifies CO₂ emissions arising from open-field straw burning in Thoai Son district, and identifies potential mitigation measures for reducing greenhouse gas emissions associated with rice straw disposal. Primary data were collected through a questionnaire-based survey of 100 rice-farming households, focusing on straw utilization and disposal practices. The results indicate that open-field burning of rice straw remains prevalent across all rice-growing seasons in Thoai Son district, with the highest intensity observed during the Winter-spring crop and the lowest during the Mid-summer crop. Consequently, CO₂ emissions from straw burning follow a similar seasonal pattern, with the Winter-spring season contributing the largest share of emissions on both total and area-normalized bases. In terms of gas composition expressed as CO2e, CH4 is the dominant contributor, while N2O plays a negligible role. Scenario analysis shows that diverting rice straw into pellet production and biochar pathways can substantially reduce CO₂e emissions, with biochar offering the highest mitigation potential. Overall, these findings provide empirical evidence to support local environmental management strategies for rice straw utilization and highlight the need for further research on the technical, economic, and policy feasibility of large-scale straw-based mitigation options.