벼 群落內에서 光收支分布와 벼 生育特性을 밝히기 爲하여 統一型品種인 來敬과 자포니카인 黃金晴을 供試하여 窒素施肥料水準을 6, 10, 14, 18㎏/10a 으로 달리하여 벼 群落의 生育狀態의 差異를 주어 生育時期別로 群落內 光分布와 光吸收量에 따른 群落의 變化와 生育과의 關係를 調査分析한 結果는 다음과 같다. 1) 來敬과 黃金晴이 葉面積指數의 品種間差異는 來敬이 黃金晴보다 높았고 窒素施肥料水準에 따라서 크게 增加하였으나 黃金晴은 N 14㎏/10a까지만 急激히 增加하였다. 2) 乾物重의 增加는 移秧後20日 까지는 品種間 窒素施肥水準間 差異를 보이지 않았지만 그 以後는 窒素施肥反應의 品種間 差異를 보였는데 來敬이 黃金晴보다 乾物生産量이 많았다. 3) 벼群落의 反射率은 移秧直後에는 水面反射率과 비슷한 6%였고 生育이 進展됨에 따라 증가하다가 出穗期에 20% 程度로서 最高에 달하였다. 4) 葉面積指數가 비슷할 때 群落反射率의 品種간 差異가 認定되었으며, 來敬이 黃金晴보다 平均 1% 程度 높았다. 5) 벼群落內에서 光減衰係數(K)는 0.23∼0.37의 範圍였으며 來敬이 黃金晴보다 낮았다. 窒素施肥水準의 增加 따라 葉面積指數는 增加하였고 光減衰係數 減少하였다. 6) 벼群落의 吸光量은 光減衰係數가 낮은 來敬이 黃金晴에 比하여 많았다. 7) 吸光量에 따른 乾物生産은 直線的으로 增加하는 傾向이었으며 窒素施肥水準이 높아짐에 따라 乾物重도 增加하였다. 品種別 乾物重增加 特性은 窒素施肥水準이 6㎏/10a에서는 서로 差異가 없었으나 N, 18㎏/10a水準에서는 來敬이 黃金晴에 比하여 높았다.

To find the effects of solar energy into the rice canopy and its balance on the rice plant growth, a Tongil type rice, Raekyeong and a japonica rice, Koganebare were used with four levels of nitrogen fertilizer application, 6, 10, 14, and 18㎏ l0a^(-1) in Chigugo, Japan. The micrometerosological data, the solar radiation and absorbed solar radiation by the rice plants, and leaf area index on cardinal growth stage of the rice community were measured. The results are as follows : Raekyeong showed increased LAI by increased nitrogen fertilizer application rates, and larger LAI than Koganebear. 1. There was no difference in total dry weight till 20 days after transplanting regardless of nitrogen levels in the same variety, after that, however, Raekyeong showed higher dry matter productions for the same durations than Koganebare. 2. In early growth stage of transplanting rice, reflection ratio of solar radiation above the crop canogy was about 6%, however, it was increased up to 20% by the increased LAI at heading date. 3. In high levels of nitrogen application plots, LAI were increased so that values were decreased. 4. Relationship between the amount of absorbed radiation by plants and its dry matter production was linearly significant. Higher levels of nitrogen application produced higher dry matter in Raekyeong, however, in lower level, the dry matter production pattern was almost similar between both rice cultivars.