Mild weather last fall allowed corn and soybean farmer Joel Abeln of New Cambria, Missouri, to finish most of his anhydrous applications. But many other farmers waited until this spring to apply anhydrous.
Abeln has many acres to cover with anhydrous every growing season, and he attempts to get about half of it covered in the fall after harvest. In some years, like this one, the weather has cooperated and he got the majority of his nitrogen applied before the busy spring fieldwork season. In other years, however, he does apply in the spring as well, side dressing later.
“The field conditions in the spring is not always the best with the soil being damp sometimes,” Ablen told DTN. “We want to set the crop up to get off the best start it can, and applying anhydrous on wet soil is not a good way to start out.”
Whatever time of year farmers apply nitrogen, there are several things they should keep in mind.
GOOD SOIL CONDITION
Having soils in good enough condition to apply anhydrous in the spring is an important consideration, according to Dan Davidson, DTN contributing agronomist. Soils that are too wet will not allow the application slot to close properly after the knife cuts through the soil. As a result, the nutrient could leak from the unsealed slot.
In addition, wet soils could cause compaction issues, which could affect the unplanted crop down the road, he said.
“The mole knife creates a shearing force on the soil, and wet soils will stick together and cause clods,” Davidson said.
Farmers who apply anhydrous — regardless what time of year it is — also need to take into consideration what the soil temperature is from 4 to 8 inches below the surface, roughly where the anhydrous is applied. Soil temperatures need to be under 50 degrees Fahrenheit when anhydrous is applied. In the spring with warmer temperatures and frequent rains that warm soil temps quickly, monitoring of soil temperatures should be done, he said.
This year, some anhydrous was applied at the end of February and beginning of March in select Corn Belt regions that have seen mild winter weather and allowed soils to thaw and dry. Davidson said he knows of anhydrous applications in Illinois, Iowa and Nebraska in recent weeks.
“It is just an odd combination of warm weather and good soil condition this winter to allow anhydrous to be applied now,” he said.
ANHYDROUS IN WINTER?
In a University of Illinois Extension report titled “Nitrogen in February?” from Feb. 22, University of Illinois Extension crop production specialist Emerson Nafziger explored the issue of whether it is a good idea to apply anhydrous in late winter. His conclusion was that it is OK to apply the nutrient at this time of year.
“If soil conditions are good, I don’t see a good reason to wait,” Nafziger wrote. “For those who prefer to wait, soils dry now means a better chance of being able to apply anhydrous with good soil conditions later in the spring.”
Nafziger points out the earlier anhydrous is applied, the greater chance it will be converted to nitrate by the time the soils are warm, and the crop is growing in the spring. Using nitrogen inhibitors will slow this conversion and will likely be as effective in February and March as it would be in the fall.
Davidson agrees that utilizing nitrogen inhibitors is a good idea, as these products protect the nitrogen in the soil. However, no product will keep 100% of the applied nitrogen available for plants. Farmers have several different products to select from, including some less expensive generic brands, he said.
N INHIBITORS: CHEAP INSURANCE
Abeln said he utilizes nitrogen inhibitors whenever he applies anhydrous, whether that is in the spring or the fall. He said he looks at this product as “a cheap insurance policy,” assuring that most of the nitrogen he applies will still be there once his crop is planted.
The north-central Missouri producer will apply anywhere from 140 to 160 pounds per acre of anhydrous in the fall or spring and then follow that up with a side-dressing application of either dry urea or UAN solution at 40 to 60 lbs. per acre. A side-dressing application of urea will occur before V10 while an application trip of UAN will be right at V10, he said.
“We look at the (fertilizer) prices then and see which one is less expensive,” Abeln said.
Many producers have moved to a two-pass application of nitrogen in corn production in an effort to provide nutrients to young plants right as they need it. Abeln said trying to get this accomplished with many acres to cover is a challenge, especially when the weather does not cooperate.
Abeln said he is “very careful” to only apply anhydrous in the spring on dry soils. A majority of his soils consist of heavy, bottomland soils, which are slow to dry, and yet another reason why he aims to get at least half of the acres applied with anhydrous in the fall.
Another issue that could arise with spring application with anhydrous would be weather delaying anhydrous application and pushing the fertilizing and planting window together. Planting corn in the days right after anhydrous application could affect the newly planted seeds negatively.
Abeln said he hasn’t had to worry about this problem much, as by planting time, he usually has all of his anhydrous applied. If this issue were to arise, he would plant other fields first, widening the time between the two field operations in these particular fields, he said.
Russ Quinn can be reached at firstname.lastname@example.org
Follow Russ Quinn on Twitter @RussQuinnDTN