1. 30년 장기 연용구의 연작 대비 윤작에 의한 옥수수 및콩의 수량증대는 옥수수보다 콩이 더 컸으며, 연작시무경운에 따라 수량이 감소되었던 옥수수는 윤작에 의해 수량이 많이 회복되었다. 콩은 연․윤작구 모두 무경운에서도 수량이 감소하지 않았다. 2. 윤작구의 작물재배기간의 이산화탄소 누적발생량은재배작물 및 처리간 차이가 없었으며, 메탄은 콩의 재배시 plow 경운구에서 생육초기에 증가하였다. 3. 아산화질소의 발생은 옥수수 생육초기 질소시비 후에질소비료의 무기화 과정에서 발생량이 증가하였는데,경운방법에 따라 차이가 뚜렷하여 chisel 경운에서 가장 높았고, 무경운에서 가장 낮았다. 4. 콩-옥수수 윤작체계에서 plow 및 chisel 경운에 비해무경운(no-tillage)의 채택에 따라 작물의 수량 감소없이 콩 재배 시 메탄 0.7 kg C ha-1 및 옥수수 재배 시아산화질소 2∼4 kg N ha-1 발생량을 감소시킬 수 있었다.
Reduction of greenhouse gas (GHG) emissions from upland crop field as well as paddy field is being required, but little information on GHG emissions according to cultivation practices in upland field is available. Soil GHG emissions during the growing season were investigated in the field of three decades rotation and tillage treatments which were consisted of plow, chiesl tillage and no tillage in west central Indiana, USA in 2006. Seasonal cumulative CO2 emissions were not different among treatments. CH4 emission increased a little in plow tillage during early soybean growing season. Most of N2O emission occurred during early corn growing season after N-fertilizer application from mid June to mid July, and was significantly affected by tillage practices in which seasonal cumulative N2O emission was significantly higher under chisel tillage. N2O emission under no-tillage was lower about 64% and 39% than that under chisel tillage and plow tillage, respectively. No-tillage practice with rotation of corn and soybean seems to be promising in point of less GHG emission and less labor for cultivation without grain yield reduction.
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