Uniform application and uptake of fertilizer is a goal strip-tillers strive to achieve on an annual basis. But timing is everything, and capitalizing on the right window of opportunity is critical.
In our latest Strip-Till Farmer podcast, Purdue University Agronomy Professor Tony Vyn asks the question of whether making a singular application of nitrogen (N) is the most efficient practice?
“We essentially have to manage our corn with the concept of no plant left behind,” Vyn says. “And that is only going to occur if every plant has the same opportunity in terms of nutrient and water access.”
Based on his ongoing strip-till research, Vyn has weighed the pros and cons of one-time N applications in either fall or spring. He suggests fall application of N is ideal in a strip-till system because it provides an expanded planting window in spring, especially on clay soils, and can allow for earlier planting and better seedbed conditions.
However, Vyn also notes that while applying 100% of N in the fall is smart from a crop safety standpoint, it’s not a wise choice from an environmental and N deficiency point of view.
“It depends on location and rainfall, but at least for the eastern Corn Belt, we don’t want to go in this direction,” he says.
So how about 100% spring pre-plant N application? This is an even riskier proposition, says Vyn, depending on the rate applied and the sandiness of the soils. Anhydrous ammonia and urea are particularly more of a gamble than UAN, especially when applied at shallow depths and directly beneath the row with little rain or time between application and planting.
“With spring applied N in a strip-till system, farmers are accepting some risk,” Vyn says. “I understand the mindset of wanting to make that one application and be done with it, but my own safety net, is to consider 25-60% of a total intended N rate as a spring pre-plant application.”
Even at those percentages, it’s still advisable to use nitrification inhibitors to keep a higher portion of that N available for later plant uptake.
“We still have a requirement to think about keeping that N in a plant available form, rather than having it go through our tile drain and down to the Gulf of Mexico,” Vyn says.
Where are you finding the most efficiency with your N applications in strip-till? Share your story with me at (262) 777-2441, or send me an email at firstname.lastname@example.org.