Technique for Deep Placement of Coated Urea Fertilizer in Soybean Cultivation
The objective of this study was to increase the productivity of soybean seeds by the application of controlled release nitrogen fertilizers (coated urea). Based on the results obtained in field experiments carried out for 3 years (1989-1991), deep placement of coated urea consistently enabled to increase the seed yield by about 10-20% over the conventional treatment. Deep placement of coated urea did not depress the N2 fixation activity throughout the growth stages until maturity, though N from fertilizer was actively absorbed. The basal deep placement of coated urea for soybean cultivation enabled to supply N from the lower part of roots without concomitant depression of N2 fixation, and consequently seed yield increased. High recovery rate (over 60%) of fertilizer N was also advantageous from economical viewpoints.
|作成者||Yoshihiko TAKAHASHI Takuji OHYAMA|