Abstract
Paddy rice plants, the variety Norin No. 29, supplied with nitrogen at various levels were grown under various light conditions, and the effects of the nutrient on the factors constituting field photosynthetic ability, respiration and dry matter productivity of the rice plants were studied. In their previous papers, the authors have postulated following farmula for the dry matter productivity of rice plants growing under community conditions. ΔW=κ·L·S·P0·ρ-Rw In the present paper, the authors elucidated that the dry matter productivity of rice plants would be estimated more accurately by the following formula; ΔW=S·P0·αI/1+αI·D-Rw where, ΔW denotes the dry matter produced per day, S:leaf area, P0 : mean photosynthetic activity per unit leaf area, D: day length, α: light curve coefficient, I:mean light intensity
