Many farmers apply all of their fertilizer before the corn crop. The concern with this practice is that nutrients such as potassium or potash can be tied up via the corn fodder or cover crop residue in the field. It can take up to two to three years before mineralization takes place within this residue and this could be yield limiting to the soybean crop.
To obtain high soybean yields, we need to provide adequate, available potash to the crop. At the very least, make a potash application before the soybean crop to manage for high yielding soybeans. It is recommended to plan at least a year in advance and plant soybeans into a good environment that is monitored and managed for a high return on investment.