「黄色種たばこ」の生育に対する燐酸施用量の影響に就いて

抄録

Bright leaf tobacco plant was cultured in a study of the relationship of the varied amount of phosphate fertilizer to the yield of dry matter, utilization of phosphate and accumulation of nitrogenous compound and carbohydrate. To a certain level, the larger application of phosphate results the higher yield of dry matter and the larger absorption rate of phosphate by tobacco plant, but upwards of the level both yield and absorption rate decrease. In this experiment the level is 60 kg. P_2O_5 per acre. At earlier stage of growth the phosphorus content of tobacco plant markedly increases according to the increasing supply of phosphate fertilizer, but at later stage the difference in phosphorus content become smaller. The nitrogen content of the tobacco plant of no phosphate plot is slightly higher than that of phosphate plot, but there is no remarkable difference in protein-N and nicotain content due to the varied application of phosphate. The contents of soluble carbohydrate in the leaves of lower phosphate plots reach to each maximam earlier than those of higher phosphate plots, so the leaves of no phosphate plot mature the earliest. When the same amount of phosphate is supplied, the tobacco plant of supplemental nutrition plot in which phosphate is mixed in row before transplanting of tobacco seedling has a larger yield of dry matter and smaller phosphate content at earlier stage of growth than that of fundamental nutrition plot in which phosphate is side dressed on about 30 days after transplanting, but at later stage its content becomes similarly. The time of maturity of leaves in the supplemental nutrition plot is later than taht of fundamental nutrition plot.