Changes in Methane Emission of Korean Rice Production Systems for the Last Two Decades and Suggestions for Methane Mitigation

Abstract

Rice (Oryza sativa L.) paddy soils are major sources of methane (CH 4 ) emission in the agricultural sector, and thus it is necessary to mitigate CH 4 emission from paddy soils. In this review, we have investigated the changes in CH 4 emission in South Korea for the last decades in relation with changes in rice cultivation area and rice production amount. We have also suggested managements for CH 4 reduction in rice cultivation systems. During the last 25 years since 1998, rice cultivation area has decreased by 30.8% and total CH 4 emission has also decreased by 33.5% accordingly. During the same period, total rice production has decreased by 23.8%, but rice production per unit area increased by 9.2% due to advances in agricultural technologies. The rice production per unit area was affected by rainfall (negatively) and air temperature (positively) in rice growing seasons, while CH 4 emissions per unit area for the last 25 years (8.10 -8.81 ton (CO 2 eq) ha -1 ) were not affected by weather conditions. However, CH 4 emissions per unit rice production (1.57 -1.97 ton (CO 2 eq) ton -1 ) were positively and negatively correlated with rainfall and air temperature, respectively, owing to the dependency of rice yield on weather conditions. Literature suggested that intermittent irrigation and shallow depth irrigation are effective in reducing CH 4 emission while increasing rice yield and saving water uses. In addition, it was also reported that minimum and reduced tillage could also decrease CH 4 emission while increasing soil organic carbon with marginal decreases in rice yield. Therefore, it may be possible to mitigate CH 4 emission by employing theses irrigation and tillage methods while maintaining rice cultivation area for food security under climate change.

Methane emission from soil surface during rice growth season under different temperature, fertilization, and rice straw input conditions

“…GIR (2022)에 따르면, 벼 재배 부문이 농업 분야 온실가스 배출 중 27.1% 로 가장 높은 비중을 차지하며, 벼 재배 면적 감소에 따라 전년 대비 22만 톤 (3.6%) 감소하였다. 하지만, 논은 여전히 온실가스인 메탄의 주요 발생원으로 작용하고 있다 (Baek et al, 2023;Lee et al, 2023). 논 토양에서 생성된 메탄은 벼 식물체의 통기 조직을 통한 운송, 토양 표층을 통한 불규칙적 분출, 그리고 대기와의 농도 차이에 의한 확산을 주요 경로로 대기로 방출된다 (Gwon et al, 2022).…”

Effects of Water Management Practices on Methane Emissions and Rice Yields in East Asian Paddy Fields: A Regional-Scale Meta-Analysis

“…따라서 농업 현장에서는 초기 분얼기와 등숙기에 최적 관개를 통해 쌀 수확량을 유지하면서 CH 4 배출량을 줄이는 간단관개 방안을 모색해야 한다(Gu et al, 2022). 최근, 논에서 CH 4 배 출 저감을 위한 논물 관리와 경운 방식에 대한 연구결과에 의하면, 간단관개와 논물 앝게대기에 의해 CH 4 배출량은 감소하고 쌀 생산량은 증가하였다고 보고하였다(Baek et al, 2023). 반면, 최소경운에 의해 쌀 생산량은 소폭 감소하 지만 CH 4 배출량은 감소하고 토양 유기탄소 함량은 증가하는 것으로 나타났다(Gwon et al, 2022;Baek et al, 2023).…”

“…최근, 논에서 CH 4 배 출 저감을 위한 논물 관리와 경운 방식에 대한 연구결과에 의하면, 간단관개와 논물 앝게대기에 의해 CH 4 배출량은 감소하고 쌀 생산량은 증가하였다고 보고하였다(Baek et al, 2023). 반면, 최소경운에 의해 쌀 생산량은 소폭 감소하 지만 CH 4 배출량은 감소하고 토양 유기탄소 함량은 증가하는 것으로 나타났다(Gwon et al, 2022;Baek et al, 2023). 이번 연구에서 CH 4 배출량을 줄이면서 쌀 수확량에 영향을 미치지 않는 물 관리 방식은 MI, AWD, FDF 순으 로 나타났다 (Fig.1).…”