2001년 국립식량과학원 인공기상실에서 수경재배로 규산의 시용 여부가 영양생장기 벼의 수분과 질소흡수량에 미치는 효과를 조사하여 규산시용 여부 및 공급된 질소의 형태별 처리에 의한 시험품종들의 수분과 질소이용효율을 산출한 결과는 다음과 같다.1. 처리 67일 후의 벼 건물중은 규산처리 시험구 및NH4+NO3 혼합시용 처리구가 규산을 처리하지 않은시험구 및 NH4 단독시용 처리구보다 유의하게 증가하였음.2. 이앙 후 67일간 조사된 벼의 수분흡수량은 규산처리와 규산 무처리 간의 차이가 없었으나 질소흡수량은규산 무처리에 비해 규산처리구에서 유의하게 증가하였음.3. 질소형태별로는 NH4 단독 시용보다 NH4+NO3 혼합시용에서 규산처리 여부와 관계없이 수분과 질소흡수량이 월등히 많았음.4. 수분이용효율은 규산처리 시험구가 규산을 처리하지않은 시험구에 비해 유의하게 증가하였으나 질소형태별 처리에서는 차이가 없었음.5. 질소형태의 혼합처리가 암모늄태 단독처리보다 질소흡수량은 유의하게 많았으나 질소이용효율은 감소하였음.

This experiment was conducted to clarify the functions of supernodulating characters on seed yield determination through the comparison of agricultural traits of supernodulating soybean mutants, Kanto100, SS2-2, and their parent cultivars, Enrei and Shinpaldalkong2. The supernodulating soybean mutants Kanto100, SS2-2 were previously characterized by their superior capabilities of nitrogen (N) fixation and photosynthesis, and thereby it is expected to offer high yields. However, it is likely to be susceptible to waterlogging during the vegetative growth stage, which frequently occurs in major soybean producing areas. The presentstudy was intended to show the effects of waterlogging on nodulation, N fixation, photosynthesis and growth of Kanto100 and SS2-2.The supernodulating cultivar Kanto100 and its normally-nodulating parental cultivar Enrei, grown in pots,were subjected to waterlogging treatment that was imposed at the successive three vegetative growth stages for two years,2005 and 2006. The waterlogging treatment significantly reduced the number and weight of nodules of both cultivars, and the magnitude of the reduction was more pronounced in Kanto100 and SS2-2. The acetylene reduction activity (ARA) of nodules and apparent photosynthetic rate (AP) of leaves were generally depressed immediately after waterlogging treatment, but both functions exhibited remarkable recovery at the pod-filling stage irrespective of cultivar. No marked cultivar difference was found in the magnitudeof the reduction of ARA per plant and AP measured immediately after waterlogging and at the pod-filling stage irrespective of year, but growth impairment was more pronounced in Kanto100 and SS2-2 in one of the two years. These results indicate that Kanto100 and SS2-2 exhibits a marked decrease in dry matter production by waterlogging, but yield decrease is compensated to level similar to that of Enrei and Shinpaldalkong2 because of its enhanced nodule growth during the recovery stage. The supernodulating cultivar Kanto100 and SS2-2 is more susceptible to waterlogging under certain growing conditions than their normally-nodulating parent cultivar.