Yes to fertilizer
The next step is making the most of the varieties you choose. “We know variety selection is most important when combined with fertility and row spacing,” notes Below.
Today’s high-powered soybean varieties demand more phosphorus than many people expect. A 70- to 80-bushel-per-acre soybean crop can draw as much phosphorus out of the soil as a 150-bushel corn crop, he explains. Don’t be fooled into thinking that last year’s P application before corn is guaranteed to meet your soybeans’ needs, Below cautions. The huge volume of residue from a hefty corn crop can tie up more than 20 pounds of phosphate and more than 100 pounds of potassium.
The bottom line: Choose good varieties, and give them the nutrients they demand.