A lot of farmers are crossing the harvest finish line for 2024 and preparing for fall tillage and anhydrous ammonia (NH3) applications, says Ken Ferrie, Farm Journal Field Agronomist.
While soil moisture levels have improved in some parts of Illinois and other states, soil temperatures are still too high in most areas.
“Maximum soil temperatures are still north of 70 degrees in many places, and part of our 4R program is to wait for those soil temperatures to get below 50 degrees before applying anhydrous with a nitrogen stabilizer,” he says. “Based on the 10-day forecast in central Illinois, it looks like November 7 will be close (to a good start date for applications).”
There are two huge potential negatives to applying anhydrous ammonia prematurely:
· Anhydrous will “gas off” in dry soil and is then lost for next year’s crop, costing you a lot of money, time and effort you can’t recoup.
· Anhydrous applied in warm soil can create an environmental problem for everyone, farmers and the general public alike.
Ferrie offers four reminders to help you make sure the product stays put once applied, so it’s available for corn next spring.
1. Soil temperature has to be right to keep product in the ground. Make sure it is no more than 50 degrees Fahrenheit – and trending downward – before making anhydrous ammonia applications this fall for the next year’s corn crop.
2. Make sure you have soil moisture available. Soil moisture is needed to temporarily hold the ammonia in place, so it can become attached to clay or organic matter in the soil, according to Iowa State University Extension.
If dry soils are cloddy and do not seal properly, the ammonia can be lost at injection, or it can seep through the large pores between clods after application.
3. If the local soil temperature is cooperating but soils are dry, Ferrie offers some ‘tricks’ that can help decrease volatility if you don’t have adequate moisture.
“One trick to lessen the volatility is to decrease the rate of ammonia you’re putting on. Lower rates need less water,” he explains. “But you’ll have to adjust the spring applications to square this rate back up.”
Another possibility is to go deeper to expose the ammonia to, potentially, more soil and more water.
“I know you retailers are cringing when I say that because, as I’ve been talking to some of you, this has been a bad year on shanks as a lot of guys are using the toolbars as subsoilers,” he notes.
4. Check behind the application rig for a good seal. Ferrie is usually most concerned about not having adequate moisture to seal applications. However, where too much moisture is present, he says the knives will smear in the soil.
“If you’re too wet to seal, the bars will be gassing off right there at application, right behind the machine,” Ferrie says. “Just because you don’t see smoke, don’t assume it’s sealing.”
He says to have someone walk behind the machine to sniff for ammonia leaks.
“My suggestion is once the toolbar goes by, someone needs to jump down on their knees and sniff the trench. If your trench sniffer is gagging for air, you’re not sealing it,” he says.
Ferrie adds that if you are doing tillage or applying anhydrous where seagulls typically drop behind the tool to scoop up worms brought to the surface – but they’re leaving and not coming back – that’s another tip the soil is leaking ammonia.
“When I get the call that a grower can still smell anhydrous in a field a day after application and wondering how much is lost, I know of no calculator or computer model that can predict that,” he says.
“You only have nitrate testing next spring to help us predict the loss. In those situations, it may be a good year to separate your strip-till from your anhydrous application,” he adds. “If you can’t get it to seal so you can get your stripping done, we can always sidedress the anhydrous next spring.”
You can listen to Ferrie’s complete instructions on his weekly Boots In The Field podcast below:
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