Effect of soil moistures on development of the soybean seeds. (Preliminary report)

Abstract

The investigation of the effect on growth and yield of soybean by soil moistures, 90∼100%, 65∼75%, 35∼45%, at the second period of growth or maturation period, was investigated in 1948. The applied soybean variety was Norin No.1 and the investigation was investigated by pots. Soil moisture contents were kept in 50∼60% similarly from the seeding period, and the soil moisture contents above described were kept since three days ago from the flowering period given, and were kept up to the yield period. The results were observed that the dry matter of top in air were in order 65∼75% plot>35∼45% plot>90∼100% plot, and that of root were 65∼75% plot>90∼100% plot>35∼45% plot. 65∼75% plot was largest on the dry matter of top and root in air. Top-root ratio were in order 35∼45% plot>65∼75% plot>90∼100% plot. The development of roots on 65∼75% plot was particularly poor. As the stem weight and the diameter of stem base, 65∼75% plot was largest and 35∼45% plot was the smallest. Soil moisture content was the smaller, number of vascular bunlle of stem was the larger. As number of pod and weight of it per plant and weight of seed, 65∼75% plot>35∼45% plot>90∼100% plot. Oil content of seed was in order 90∼100% plot>65∼75% plot>35∼45% plot, and protein content of seed was opposite. From the view-point of the result of investigation, it seems that most sutable soil moisture content to growth of soybean at the second period of growth and maturation period is about 65∼75%. As oil and protein content of seed, 65∼75% plot is in second order, but the differentiation from the other two plots is comparatively small, and from the view-point of the yield of these composition, too, about 65∼75% soil moisture content is most sutable.