녹비작물 종류에 의한 토양 및 벼 탄소량의 변화

Changes in Carbon Amount of Soil and Rice Plant as Influenced by the Cultivation of Different Green Manure Crops

녹비작물은 토양에 환원하여 이용하면 화학비료 절감, 토양의 물리화학적 특성 개량, 토양유실방지, 경관조성 등 다양한 역할을 수행한다. 녹비작물을 농경지에 환원하는 과정에서 발생될 수 있는 탄소 변화를 알아보고자 논토양에 녹비보리, 헤어리베치, 헤어리베치/보리, 화학비료구를 처리하였다. 겨울동안 녹비작물을 통하여 흡수된 탄소량은 헤어리베치는 1.22 ton $ha^{-1}$, 녹비보리는 1.24 ton $ha^{-1}$이었으며 헤어리베치/보리 혼파구는 1.54 ton $ha^{-1}$ 이었다. 토양 탄소함량은 벼 이앙 7일전에 가장 높았으며 이후부터 점차 낮아져 수확기까지 비슷한 경향이었다. 녹비종류별로는 헤어리베치와 녹비보리구에서 헤어리베치/보리 혼파구보다 높았다. 메탄 발생량은 모든 처리에서 이앙 후 7일에 가장 높았으며, 녹비 환원구에서 화학비료구보다 약 17 ~ 25배 더 많았다. 녹비종류별 메탄 발생량은 헤어리베치, 헤어리베치/보리, 녹비보리 순이었다. 벼 식물체의 탄소 흡수량은 벼 재배기간 동안 계속 증가하였으며 녹비종류별로는 차이를 보이지 않았다. 수확기의 정조와 볏짚 생산량은 녹비환원구에서 화학비료구보다 5 ~ 13% 많았으며 특히 헤어리베치/보리 혼파구에서는 14.07 ton $ha^{-1}$으로 가장 많이 생산되었다.

A green manure crop were used in many ways, such as for reducing chemical fertilizer, improving physical and chemical properties of soils, protecting soil loss, and creating landscape when it's grown in agricultural land. Experiments were conducted to find out carbon emitted with applying green manure crops in paddy field. Amounts of carbon absorbed in the green manure crops during the winter were 1.22 ton $ha^{-1}$ in hairy vetch, 1,24 ton $ha^{-1}$ in barley, and 1.54 ton $ha^{-1}$ in hairy vetch/barley. The soil carbon content was the highest at days before transplanting of rice and decreased after days after harvesting the plant. Soil carbon contents were higher with hairy vetch or barley treatment than with hairy vetch/barley treatment. The content of emitted methane ($CH_4$) was the highest at 7 days after transplanting rice plant, and was 17 ~ 25 times higher with green manure treatments than with chemical fertilizer application. The $CH_4$ emission was the highest with hairy vetch treatment and than followed by hairy vetch/barley and barley treatments. The content of carbon absorbed in rice plant increased during the cultivation period but was not different with the applications of different green manure crops. The yield amounts of rough rice and rice strow were 5 ~ 13% higher with the green manure treatments than the chemical fertilizer application. In particular, they were the highest with hairy vetch/barley treatment as 14.07 ton $ha^{-1}$.