작기 중 물관리를 실시한 휴경기 논에서의 온실가스 배출 특성 조사 : 순 지구온난화지수 산정(net GWP)

Abstract

Approximately 51% of the greenhouse gas (GHG) emissions generated by the agricultural sector in Korea are emitted from rice fields. Despite the extended fallow season, the calculation of GHG emissions from rice fields has been limited to rice cropping season. In this study, we sought to provide information on GHG emission considering the carbon budget in the fallow season. To compare the influence of water management during cropping season and how it affects the fallow season, two different treatments were examined, continuously flooded (CF-fallow) and intermittent drainage (ID-fallow). The emission rates of methane (CH₄), nitrous oxide (N₂O), and carbon dioxide (CO₂) were monitored using the closed chamber method. Changes in soil carbon were estimated using the net ecosystem carbon budget (NECB) method and the net global warming potential (GWP) calculated. Seasonal CH₄ and N₂O emissions were not significantly different between treatments, but the seasonal CO₂ emission for CF-fallow was significantly higher than that of ID-fallow. The net GWP was 5062 ㎏ CO₂-eq. haSUP-1/SUP for CF-fallow and 4433 ㎏ CO₂-eq. haSUP-1/SUP for ID-fallow. Approximately 77% of the calculated net GWP value was affected by the NECB value, followed by 22 ~ 23% affected by N₂O emission. In contrast, the influence of methane on net GWP was less than 1%, suggesting little effect on GHG emissions. In order to reduce GHG emissions during the fallow season in rice paddies, carbon enhancement through the input of carbon sources into the soil should be employed. However, since there are concerns about increased CH₄ emission from decomposing organic material during the cropping season, additional research on appropriate organic material sources and application methods should be conducted.