Soybeans were scouted at the V3 growth stage and yellowing of lower (older) leaf margins were observed.
This issue was confirmed by an NC State Extension Specialist as a Potassium (K) Deficiency. Stunted plants or slow growth can be associated with a potassium deficiency. Soybeans require a high amount of potassium and uptake of K is driven by diffusion. In an environment of droughty conditions a K deficiency may be seen. The best way to ensure and maintain the correct nutritional needs for a field is to conduct soil sampling every 1 to 2 years.