Influence of the Soil Moisture on the Grwouth and Harvest of Soybean Day-Length and Temperature upon the Riping Period of Soy-Beans

Abstract

This research was conducted to make clear the influence of soil moistures in the growth and harvest of soybean. Sandy soil (the water capacity was about 28%) was used, and the soil moistures were kept constant at 30%, 50%, 70% and 90% of the water capacity in each experimental plot respectively. The variety used was Summer Soybean No.1. The summary of the results are as following. 1. The soil temperature observed was higher for lower soil moisture, and fell in proportion to the increase of soil moisture. 2. With soil moisture at an extent of 30%, the germination of soybean was somewhat obstructed. 3. The length, number of nodes, and size of main stem of the plant harvested were in proportion to soil moisture. 4. There was generally not large difference in the average date of flowering. 5. Number of flowers, pods, percentage of fructification, number and weight of seeds were bigger in proportion to soil moisture, but dry weight of one hundred seeds, became bigger as soil moisture decreased. 6. There was generally not large difference in the harvest time. 7. Among the chemical components of seeds, oil content was found to increase as soil moisture decreased, but the difference was very little among all soil moisture plots. On the other hand, protein content was large in proportion to soil moisture, and the differences among the lots comperatively great. 8. Taking into account the growth, flowering, fructification, yield and component of seed, there was observed a remarkable differences of effect between 30% and 50% of moisture content. 9. The best results in growth and harvest of soybean, were obtained when the moisture was kept at 90% of the capacity.