논에서 SRI (System of Rice Intensification) 물 관리 방법을 적용한 온실가스 저감 효과

Abstract

논에서 온실가스 배출에 영향을 주는 가장 큰 요인인 물관리를 통하여 온실가스 감축효과를 파악하고자, 춘천시 신북읍 천전리에 위치한 강원대학교 벼 시험포장에서 메탄과 아산화질소 배출 시험을 수행하였다. 벼 재배에서 상시담수, 간단관개 (중간낙수 1회 처리, 6월 11일~6월 20일) 그리고 SRI 물 관리 농법 처리 등을 조성하여 수량, 쌀의 품질, 온실가스 배출량 비교 및 온실가스 감축효과를 조사한 결과는 다음과 같다. 1. 물 관리별 벼 수량은 SRI 처리에서 <TEX>$6,341kg\;ha^{-1}$</TEX>로 가장 수량이 높았으며, 상시담수 (CF)에 비해 간단관개(ID)와 SRI 처리에서 각각 13.8%와 11.3% 증수되었다. 2. 재배기간 중 시기별 용수 사용량은 상시담수 처리가 <TEX>$46.6m^3$</TEX>, 간단관개 <TEX>$39.5m^3$</TEX>, SRI 물 관리 <TEX>$24.5m^3$</TEX>로 나타나, 상시담수 대비 각각 15.2% (간단관개), 47.4% (SRI)의 농업용수를 절감한 것으로 나타났다. 3. 벼 재배기간 온실가스 총 배출량을 지구온난화잠재력(GWP)으로 환산한 결과, 상시담수에 비해 간단관개가 65.5%, 그리고 SRI 물 관리 농법은 71.8%의 온실가스 감축효과가 있는 것으로 나타났다. Water competition among domestic, industrial and agricultural sectors has been gradually heightened recently in Korea as the lack of water supply is expected in the near future. About 46% of nation's water use is consumed in paddy farming to produce rice. And the conservation of water resource and quality in agricultural sector is a pending issue in the nation's long term water management plan. New paddy rice farming techniques that use significantly less irrigation water are urgently required. System of Rice Intensification (SRI) that is now well known to produce more rice with less water consumption has not been tried in Korea yet. And environmental effect of SRI on greenhouse gases (GHGs) has not been well investigated. The objective of this study was to measure the effect of SRI on GHGs as well as water use and rice yield in a Korean paddy condition. Three experimental runoff plots <TEX>$5{\times}15m$</TEX> in size were prepared at an existing paddy field. Runoff, GHGs emission and water quality were measured during the 2011 growing seasons while a Japonica rice variety was cultivated. Rice plants grew better and healthier in SRI plots than in continuously flooded (CF) and intermittently drained (ID) plots. Rice yield from SRI plots increased 112.8 (ID)~116.1 (CF)% compared with CF and ID plots. Irrigation requirement of SRI plots compared to CF plot reduced by 52.6% and ID plot reduced by 62.0%, meaning that about 37.9~47.4% of irrigation water could be saved. GHGs emission from SRI plots reduced by 71.8% compared to that from CF plot and by 18.4% compared to that from ID plot, meaning that SRI could help contribute to ease the greenhouse gas accumulation in the atmosphere. It was believed that SRI is a promising paddy farming technique that could increase rice yield, and reduce irrigation water requirement and GHGs emission not just in Korea but also other rice farming countries all over the world. However, it was recommended that long term studies under different conditions including rice variety, soil texture, water source, climate need to be conducted for reliable data for the development of environmental policies related to GHGs emission control and management.