Growth and yield of soybean plants as affected by the deficient soil moisture content at different growing stage.

[摘要] We have investigated on the growth and yield of soybean plants which were treated with deficient supply of soil moisture during 15 days at different growing stage and obtained the following results. (1) 1st series plants (treated during l5 days-period after the date of flower-bud differention) Vegetative growth was prevented. Many flowers were dropped, resulting few pods obtained as compared with the control plant. The average weight of one seed was light and this series showed the poorest yield. (2) 2nd series plants (treated during 15days-period after the date of flowering) Vegetative growth was prevented. Number of flowers was very few. Because many flowers and pods were dropped without growing to ripening, only few pods were obtained, showing the poorest yield except that of 1st series. (3) 3rd series plants (treated during 15 days-period after the date of the flowering season) They showed only few dalayed flowers and the dropping of pods were fewer than the 1st and 2nd series. Yield was greater than that of 1st and 2nd series. But it must be mentioned that they have the highest percentage of abortive seeds of all experiment series. (4) 4th series plants (treated during 15 days-period in the process of ripening) Vegetative growth and ripening process of the plants was similar to that of control plant, but the average weight of one seed was lightest of all. (5) In every series, with regard to the buds which were formed until July 20, no dropping was observed. (6) In every series, it was observed that the 1st peak of seasonal dropping of flowers took place at the same time as the formation of pods had increased to some extent, and it was also seen in 1st and 2nd series that the flowers were dropped severely when the soil moisture was increased suddenly to 70%, after the drought treatment period had finished. (7) It was recognized that when the pods grows to some definite extent, they are very easy to drop, and that growth extent scale is not differ between these five series. (8) These results may be explained as the direct effect of deficient soil moisture content on the fertility of soybean plants, but further the disturbance of nutrition which might be occurred accompanied with the insufficient supply of soil moisture should undertake a great deal to determine the fertility of soybean plants.

[学科分类] 农业科学（综合）