Effect of Soil Moisture Content at Various Growing Periods on Growth and Yield of Soybean. : II. Changes of nitrogen and carbohydrates in soybean plant as affected by abundant and defficient soil moisture content.

Abstract

The differences of Chemical composition of soybean as affected by various soil moisture contents were investigated by pot culture, in 1956 and 1957. The results many be summarized as follows: 1) In DW (plots subjected to wet condition after dry condition), wet condition of soil (75 % of maximum water capacity) in seedling period retarted the accumulation of nitrogen and carbohydrates in the late stage of growth and decreased yield of grain. In WD (plots subjected to dry condition after wet condition), yield of grain were not affected by wet condition. 2) Wet condition of soil (in DW and WD) in the previous period of flowering does not affected the yields of grain remarkably. 3) In DW and WD, wet condition of soil in the flowering period increased the accumulation of nitrogen, carbohydrates and yield of grain strikingly. Especially in DW, translocation from vegetative organs to grain was presumably smooth. 4) In DW, wet condition of soil in the fruiting period decreased the amounts of carbohydrates in vegetative organs and increased the amounts of fat and yield of grain. In WD, yields of grain were not affected by wet condition. 5) Generally, in the case of DW the percentage of nitrogen content of grain increased more rapidly than WD, On the contrary, in the case of WD the increase of parcentage of fat content of grain took place very strikingly. In this study, the effect of deficient soil moisture content (45 % of marimum water capacity) are contrary to the effect of abundant soil moisture content and the results in the former was abbreviated.