See more from this Session: Management Impact On GHG Emissions and Soil C Sequestration: III
Increase of CH4 emission in No-tillage Paddy Soil during Rice Cultivation
Sang Yoon Kim1), Jessie Gutierrez1) and Pil Joo Kim1,2)*
1) Division of Applied Life Science (BK 21 Program), Gyeongsang National University, Jinju, 660-701, South Korea
2) Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, 660-701, South Korea
Concerns for the reduction of greenhouse gases emissions like methane (CH4) from agricultural activities led to the recommendation of various best management practices to control CH4 emission from paddy rice cultivation such as conservation tillage or no tillage. We report a new finding, which showed higher CH4 emission with long-term no-tillage system during rice (Oryza sativa L., cultivar Dongjinbyeo) cultivation under identical water and fertilizer management by comparison with conventionally tilled cultivation. Closed chamber measurements were used to monitor daily CH4 fluxes, to describe the seasonal pattern of CH4 emissions and estimate total CH4 fluxes on a field-trial during rice growing season. Soil Eh, temperature and plant growth and yield were also monitored. Daily CH4 emissions followed typical CH4 emission patterns but were higher in the no-tillage field. Total CH4 emission under no-tillage was 2.5-fold higher at 45.25 g CH4 m-2 than by tillage at 17.97 g CH4 m-2. As previously reported, CH4 production could be potentially related to organic carbon (C) content in soil. In our study, higher amount of labile C as hot water extractable C (CHWE) were detected in the no-till treatments, especially at its upper surface layers (0-5 cm depth) than conventional tillage. As a result, this higher accumulation of soil organic matter in no tillage system might have activated more methanogenic Archaea and then influence higher CH4 emissions during rice cultivation.
Keywords: No-tillage, Conventional tillage, CH4 emission, Rice paddy soil, Hot water extractable carbon