No 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.