Abstract
The purpose of this experiment was to examine whether the foliar application of urea is effective as a countermeasure against excess moisture injury of soybeans [Glycine max (L.) Merr.]. During the flowering period, soybean plants cultivated in pots were treated with three soil moisture conditions: excess moisture (water table of 5 to 7 cm below the soil surface), flooding (water table of 2 to 3 cm above the soil surface) and control, and a fertilizer solution contailling 1% urea was sprayed on the plants. The soil treatments and foliar application continued for 7 and 14 days, respectively. In the excess moisture and flooding plots, since the nitrogen content increased with the foliar application, photosynthesis was promoted and dry matter production increased. The increase in the number of pods and seed weight by the application brought about an increase in seed yield in these plots. In the excess moisture plot with application, these values were nearly the same as these of control plot. In the control plot, the foliar application was not so effective as in the other plots. As a result, soybean plants could escape the damage by the foliar application of urea during the flowering period even under conditions of excess moisture with the water table of 5 to 7 cm below the soil surface. Also, even under 7-day flooding conditions, the damage was reduced to some extent by the application.
