Growers should not expect higher yields from banding fertilizer, Extension experts note.A four-year study at Arlington, WI, found no yield advantage for deep banding, compared with broadcast fertilizer or a planter-placed band, says Richard Wolkowski, a University of Wisconsin Extension soil scientist. The same is true in Illinois, Fernandez says. “Deep banding is sometimes suggested because it makes the nutrient more available, but we have not seen evidence of that.” In Illinois, data doesn’t support lower application rates with banding, either, he adds.

However, “the tillage effect of deep placement might provide some benefit,” Wolkowski says, “since it will remove some compaction and surface residue in the row. This should allow for better planting conditions.”

Wolkowski and Fernandez also remind growers that the likelihood of any plant response to applied P or K depends on your soil test levels and the weather. In high-testing soils, the probability of a yield response to added nutrients is quite low. “Cooler seasons tend to show a greater response potential, whereas seasons like 2010, where heat units were not an issue, are less likely to respond,” Wolkowski says.

Since they started banding about six years ago, the Jahns have cut their P and K use in half. They inject a base rate of 40 lbs./acre of 11-52-0 and 60 lbs./acre of 0-0-60, then vary the rate on the go, according to soil tests, applying as much as 150 lbs./acre of each material in certain areas. They also spread hog manure every fourth or fifth year. In most fields, their soil tests are in the high range for both P and K.

Their goal is to feed the current crop, Rick says, although, “if we were on weaker soils, I don’t know if I’d be comfortable with a half rate.” The Jahns soil test every two years on 2.5-acre grids from the same georeferenced points each time. “So we should see in a timely fashion if we’re losing fertility,” Rick says. His thinking: “Why spend money on fertilizer if you don’t have to?”

Before they bought their own equipment, the Jahns had hired a neighbor with a strip-till rig to band nutrients in the fall. They bought their own air cart and RTK system in 2008 and expect to recoup their $100,000 investment in about four years – just from fertilizer savings, Rick says. In 2008, when fertilizer prices shot up, “we paid for about a third of the system in one year by going to a half rate.”

In 2010, the Jahns put their system to an extreme test when they planted a 30-acre field of corn-after-corn with no tillage beyond the fertilizer knives. Though he doesn’t plan to repeat the experiment, Rick says the field produced an excellent crop, yielding 190 bu./acre.

That was no accident, Lagerstedt says. “Planting over the fertilizer band got the crop off to a good start.”