If soybean roots are properly nodulated, then fertilizer N is not necessary. Proper nodulation usually occurs if soybean has been grown in the same field within the last 3 years and/or proper soybean inoculation occurred.
Preplant/starter N applications have been shown to provide no benefit. Residual N, mineralized N, and N that comes with P fertilizers have not been found to be detrimental to soybean yields. Even N applications for double cropped soybeans (soybean after wheat) have not shown yield benefit. Late season N (R3-R5) applications do not tend to reliably increase yields. In rare situations, high yielding irrigated fields can benefit from application of small quantities (<60 #) during early seed filling.
“For more information on this or other topics related to soybean production, contact your state extension specialist or your local extension educator/agent.”
The following is the link to the soybean extension specialists: state extension soybean specialist
