Effects of Nitrogen Level and Defoliation at Maturing Stage on the Yield Components of Rice

질소시용량(窒素施用量) 및 등숙기(登熟期) 절엽처리(切葉處理)가 수도수량구성요소(水稻收量構成要素)에 미치는 영향(影響)

We have studied the responce of nitrogen on the newly bred varieties, Yusin and Milyang #23, and the effects of defoliation at maturing stage on the rate of ripened grains under different nitrogen levels. The results obtained are summarized as follows : 1. Milyang #23 as well as Tongil was found to be highly nitrogen responsive variety and showed good grain maturing percentage. The number of grain per unit area affected the total yield under the high levels of nitrogen application. The variety, Yusin, was less responsive to nitrogen and had also less leaf area than other varieties under the high level of nitrogen application. Yusin also seemed to have low maturing percentage due to unbalanced ratio between photosynthetic area and size of storage. 2. The low internodes and leaf blade of Yusin and Milyang #15 were grown too much under high levels of nitrogen and these caused more lodging and less light penetration in pant canopy. 3. The effects of defoliation at maturing stage on yield was high under the high levels of nitrogen application, especially when defoliation was done early stage of maturing. The effects of defoliation appeared to be greates in Tongil than in Milyang #15.

수도(水稻) 신품종(新品種) 유신(維新), 밀양(密陽)23호(號)들의 질소반응(窒素反應), 수량(收量) 제한요인(制限要因) 등숙기절엽(登熟期切葉)의 영향등(影響等)을 5개(個) 질소수준하(窒素水准下)에서 검토(檢討)하였던 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 밀양(密陽)23호(號)는 통일(統一)과 같이 내비성(耐肥性)이 컸으며 등숙(登熟)이 양호(良好)하여 입수(粒數)가 수량(收量)을 제한(制限)하나 유신(維新)은 내비성(耐肥性)과 최적엽면적(最適葉面積)이 크지 못하고 다비조건하(多肥條件下)에서는 동화기관(同化器官)에 비(比)하여 수용기관(受容器官)이 과다(過多)하여 등숙(登熟)이 불량(不良)한 것으로 보였다. 2. 유신(維新)과 밀양(密陽) 15호(號)는 다비하(多肥下)에서 하위절간(下位節間) 및 엽신(葉身)이 과도(過度) 신장(伸長)하여 도복(倒伏) 및 투광면(透光面)에서도 불리(不利)한 것으로 보였다. 3. 등숙기(登熟期) 절엽(切葉)의 영향(影響)은 등숙초기(登熟初期) 및 다비조건하(多肥條件下)일수록 크고 밀양(密陽) 15호(號)보다 통일(統一)이 비교적(比較的) 큰 것으로 보였다.