중질소(重質素)를 사용(使用)한 두과사료작물(豆科飼料作物)의 질소(窒素) 고정량(固定量) 측정(測定)에 관(関)한 연구(硏究)

Studies on Nitrogen Fixation of Forage Legumes with ¹⁵N-Ammonium Sulfate

화본과(禾本科) 및 두과사료작물(豆科飼料作物)의 단파(単播)와 혼파(混播)에서 중질소(重窒素)를 시용(施用)하여 시비질소(施肥窒素)의 작물별(作物別) 건물수량(乾物收量), 질소흡수량(窒素吸收量), 질소고정량(窒素固定量)에 대(対)한 질소(窒素)의 효과(効果)를 조사(調査)하였다. 1. 두과작물(豆科作物)에서 질소고정량(窒素固定量)은 alfalfa > red clover > birdsfoot trefoil의 순(順)이었으며 토양질소의존도(土壌窒素依存度)는 red clover가 가장 컸다. 2. 건물수량(乾物收量)에 대(対)한 질소시용효과(窒素施用効果)는 orchardgrass에서만 높이 인정(認定)되었고 alfalfa와 birdsfoot trefoil는 혼파(混播)의 경우 초기(初期)에만 인정(認定)되었다. 3. 건물수량(乾物收量)은 단파(単播)에서는 alfalfa > red clover > orchardgrass > birdsfoot trefoil의 순(順)이고 혼파(混播)에서는 orchardgrass + alfalfa > orchardgrass + red clover > orchardgrass + birdsfoot trefoil순(順)으로 나타났다. 4. 질소흡수량(窒素吸收量)은 전구(全区) 공(共)히 시비구(施肥区)가 무비구(無肥区)보다 증가(増加)하였고 단파시(単播時) alfalfa > red clover > orchardgrass > birdsfoot trefoil순(順)으로 작물별(作物別)로 흡수량(吸收量)의 차이를 보였다. 5. Orchardgrass의 질소흡수량(窒素吸收量)은 3:7의 red clover 혼파(混播) 시비구(施肥区)만 제외(除外)하고 시비(施肥)에 관계없이 파구(播区)가 단파구(単播區)보다 높았다.

Effects of nitrogen applied to grown alone and in mixture with grass and legumes of forage crops on the yield of dry matter, absorptivity, and the amount of nitrogen fixation were studied using $^{15}N$ ammonium sulfate. 1. The amount of nitrogen fixation in legume was decreased in order of alfalfa > red clover > birdsfoot trefoil, and red clover gave highest soil-nitrogen dependency. 2. Fertilizer nitrogen for the yield of dry matter was highly effective only in orchardgrass, and effective at the early stages of alfalfa and birdsfoot trefoil in case of a mixed sowing. 3. Alone and mixed sewings showed the yield of dry matter in decreasing order of alfalfa > red clover > orchardgrass > birdsfoot trefoil and orchardgrass + alfalfa > orchardgrass + red clover > orchardgrass + birdsfoot trefoil, respectively. 4. The plot of with nitrogen showed greater nitrogen uptake than the plot of without-nitrogen throughout the plots. In case of grown alone, however, difference in the absorptivity of various forage crops was decreased in order of alfalfa > red clover > orchardgrass > birdsfoot trefoil. 5. Regardless of nitrogen application, nitrogen uptake amount of orchardgrass was higher in the plot of mixture then in the plot grown alone, except the with nitrogen plot of red clover grown in mixture at the ratio of 3 : 7.