Rains have interrupted the final stretch of harvest season and early field work, but those looking to apply anhydrous are likely to find good conditions this fall.
After the summer drought, advice from agronomists was to wait for some moisture to get into the ground. The late-October rains should do just that.
“If you had dryness, you should wait until that rain moistens things down 5 or 6 inches,” wrote Angie Rieck-Hinz, Iowa State University Extension field agronomist in north central Iowa in a blog post. “This will delay conversion of the ammonium to nitrate and reduce leaching losses with high rainfall in the fall or early spring.”
Anhydrous prices are on the rise at the end of October, with the most recent update from DTN showing a 6% increase to $809 per ton. That is just below prices at this time in 2021, before they spiked for the entirety of 2022. Prices are still $600 below this time in 2022.
Offsetting the price difference from a year ago are corn prices that are nearly $2 per bushel lower than late October 2022.
University of Minnesota Extension educator Brad Carlson said that using an inhibitor could help protect against nitrogen losses if a lot of moisture comes into play this offseason.
“Use of a nitrification inhibitor is a hedge against extreme conditions that could lead to nitrogen loss between application and the time the crop is up and using it,” he said. “The period before using it is between now and next year’s crop in next May or June, so that’s a long time.”
One key factor to remember is to watch soil temperatures closely. Carlson reminds people to wait until temperatures are consistently below 50 degrees at the 6-inch depth before applying. A cool-down expected to come in the last week of October and early November may help.
He said anhydrous ammonia has proven to be the most effective fall-applied fertilizer, with other products such as urea showing more effectiveness with spring applications in University of Minnesota research, but “mileage may vary” in other locations.
Inhibitors aren’t a reason to get sloppy in applications, however, as they are no substitute for proper depth and timing.
“If soil moisture conditions are questionable, make a pass around the field,” she said. “If you can smell ammonia, make adjustments to equipment or wait until conditions are more suitable.”
In Missouri, fall application of nitrogen fertilizer is considered “relatively high risk,” according to the University of Missouri. The cost is often lower at this point and can pay off if there are no issues.
“Only anhydrous ammonia should be used for fall N applications,” they wrote. “All N fertilizers convert to nitrate in the soil, and nitrate is the form of N that can be lost. Ammonia converts to nitrate slower than any of the other forms of N, and risk of loss is much lower than for any other form.”
They also suggest not fertilizing all the acres intended for crops that use the nitrogen fertilizer. That will lessen the risk of loss, particularly if a significant nitrification event comes through.
“It balances the convenience of fall N application with the economic and environmental risks,” they said. “The risk of losses from fall N applications increases in Missouri the farther south you go. The University of Illinois recommends that no fall N applications be made south of Highway 16 in Illinois, which roughly corresponds to Highway 36 in Missouri running from St. Joseph to Hannibal.”
Source - https://agupdate.com
