Effect of Soil Moisture Content at various Growing Periods on Growth and Yield of Soybean. : I. Changes of growth, flowering, fruiting, exudation and water requirement as affected by abundant and deficient soil moisture content.

Abstract

The difference of growth, flowering, pod-setting, fruiting, exudation and water requirement of soybean as affected by changed of soil moisture content was investigated by pot culture, in 1956 and 1957. (1) In DW, Wet condition of soil (75% of maximum water capacity) in seedling period decreased dry weight of roots, amount and nitrogen content of exudation-sap in the period of flowering to fruiting, and then decreased the percentage of pod-setting and yield of grain. (2) Wet condition of soii (DW and WD) in previous period of flowering did not affected the yield df grain. (3) In DW and WD, wet condition of soil in flowering period increased dry weight of roots and efficiency of exudation, amount and nitrogen content of exudaton-sap, number of flowers, and then increased the percentage of pod-setting, number of pods and grain, and yield of grain. (4) Wet condition of soil (DW and WD) in fruiting period increased amount and nitrogen content of exudation-sap in late growing period, and then increased weight of 100 grains. In the only case of DW, the treatment increased yield of grain. (5) Abundant soil moisture content in culture of soybean increased water requirement. In this study, the effects of deficient soil moisture content (45% of maximum water capacity) are contrary to the effects of abundant soil moisture content and the result in the former was abbreviated.