In this week’s Boots In The Field podcast, Farm Journal Field Agronomist Ken Ferrie addresses a 4R-type question regarding strip-till fertilizer placement. The grower says he currently is strip-tilling phosphorus (P) and potassium (K) ahead of corn and also broadcasting some P and K ahead of his soybean crop. He’s contemplating changing his practice in soybeans.
The grower’s specific question was asked in two parts: “Would strip-tilling fertilizer ahead of soybeans increase efficiency, in terms of increasing yields? If so, with that improved efficiency, could I reduce the amount of fertilizer I apply?”
Ferrie began his response by asking the grower about his current row spacing in soybeans.
“Are you in 30-inch beans, and do you plan on planting into the strip? Our data from test plots show a yield advantage to narrow-row beans planted at the same population as wide-row beans, along with better weed control,” Ferrie noted. “If you change to 30-inch rows, you may be giving up some yield and weed control that stripping may not make up for. If you’re already in 30-inch rows, this wouldn’t be a concern.”
The grower responded by telling Ferrie he is stripping in 20-inch corn and would be using the same bar to strip into 20-inch soybeans.
Consider The Amount Of Residue Present
Ferrie noted, “From experience, I can tell you that trying to run a 20-inch strip bar with fertilizer knives on it through 250-bushel corn stalk residue in the fall is a major challenge. Sometimes, getting it to flow through a 30-inch strip-till bar can even be a challenge. Twenty-inch rows just don’t leave a lot of room to put all that fresh residue through the machine in the fall.”
However, Ferrie did consider the benefits that might be available if the farmer could get through the residue adequately. For one, the strips would allow for a warmer spot to plant soybeans next spring. This could aid in early planting situations to get the beans out of the ground quicker.
“We know this is especially true when we’re planting into cover crops compared to no-tilling into covers,” he said. “However, with that said, our test plots do not show a consistent enough response to strip-till beans over no-till that’s high enough to pay the bill.”
Consider Nutrient Removal Rates
As for improving fertilizer efficiency with a banded strip to the degree the farmer could reduce total fertilizer amounts, Ferrie said the lack of efficiency would have to be causing a yield drag in the grower’s current program.
“That can occur in low-testing soils or in soils that have a lot of fertility tie-up, such as in calcareous soils,” Ferrie said. “But soybean yields are created a lot later in the growing season, during pod fill. In our test plots, many times we see visual effects of our planter fertility, but it’s been hard to get that to correlate to a yield increase here in central Illinois.
“With soybeans, just because the crop is bigger and taller in the beginning of the season that doesn’t mean it’s going to yield more in the end,” he said.
While banding fertilizer can make it more efficient, it doesn’t change the law of nutrient removal rates. Applying less fertilizer than removal rates call for over time will deplete the soil.
“Based on our plot results, we are struggling to get a yield advantage in our strip-till soybean plots high enough to pay the bill,” Ferrie said. “But the good news is we’re not seeing a yield loss to strip tilling, either.”
Consider The Availability Of Subsidies
Something Ferrie encouraged the grower to consider is whether he is getting or able to tap into subsidies for subsurface banding of phosphate and for using cover crops.
“We have some growers (in central Illinois) who can pick up $45 an acre by subsurface banding P and another $30 per acre on the cover crops,” Ferrie said. “This would go a long way of shoring up some of the cost involved, even if there wasn’t a yield advantage. My advice would be to experiment on your farm on a small scale before going whole hog to see if it’s going to fit your operation.”
Listen to the complete Boots In The Field podcast here:
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