ScholarWorks@경상국립대학교

초록

This study was performed to determine the changes in methane emissions under different water management methods during rice cultivation in response to climate change. To study the diurnal variations in methane emissions from July to September 2022, in the Apgok-ri area of Gungryu-myeon, Uiryeong-gun, a closed chamber method was used at 4-hour intervals. The treatments were conventional (CONV), mid-season drainage for 2 weeks with low level water management (2MD-1) and alternate water irrigation (2MD-2), mid-season drainage for 3 weeks with low level water management (3MD-1), mid-season drainage for 4 weeks with low level water management (4MD-1) and alternate water irrigation (4MD-2). From July to August, methane emissions were highest at 14:00 and lowest at 02:00 in all water management treatments. In July, the treatment with the highest average methane emission was the CONV (29.1 mg m-2 hr-1). The reductions in methane emissions compared to CONV were as follows: 2MD-1 (51.4%), 2MD-2 (53.8%), 3MD-1 (68.5%), 4MD-1 (70.2%), and 4MD-2 (71.8%). Similarly, from August to September, methane emissions were reduced by 31.3% to 70.3% through water management. As the duration of mid-season drainage increased, methane emissions decreased, with alternate water irrigation proving more effective in reducing methane emissions compared to low water management. Therefore, as a method to reduce methane emissions in paddy fields, it is most effective to implement mid-season drainage in July (approximately 40 days after transplanting). After mid-season drainage, alternate water irrigation is expected to reduce methane emissions. Such water management practices in rice cultivation could contribute significantly to mitigating climate change by lowering methane emissions.

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