From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335

Summer 1998, No. 8


Soybeans require high levels of available nutrients from planting to harvest. Adequate fertility will not guarantee top profit soybeans, but top profit yields cannot be obtained without these vital inputs. The soybean plant, just like a factory, requires a minimum level of raw materials to generate grain as the finished product. The goal is to supply the amounts needed and on a schedule tuned to soybean plant and seed development.

Stimulate rapid seedling development. How? Auburn scientists used starter fertilizer (45 pounds per acre nitrogen) to boost grain yield. For the determinate variety, Cook, starter boosted seed yield (from 32 to 37 bushels per acre), vegetative growth, plant height and the nitrogen content in plant tissue. Phosphorus and potassium can be included with band placed starter nitrogen.

Up-front feeding benefits soybeans. Fertilizing wheat for both crops should work...and it does much of the time. However, several conditions exist which increase soybean response to split applications and late season fertilization.

Direct soybean fertilization deserves consideration. An Illinois consulting firm's research tells why. The same reasons hold true for the Southeast. Program soybean fertilization to supply crop needs throughout the growing season. The period of greatest potassium uptake is during the 15 days between full bloom and early pod fill. For phosphorus, uptake intensifies from full bloom to seed maturity. For some soils, fertilizer applied to wheat can do the job. For many sandy Coastal Plain soils, high yield, high profit soybeans will likely respond best to a well fertilized wheat crop plus fertilizer directly applied to the soybeans.


For more information, contact Dr. Noble R. Usherwood, Southeast Director, PPI, 655 Engineering Drive, Suite 110, Norcross, GA 30092-2837. Phone (770) 825-8070.
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