AgWatch


Benefits Of Urea

Specialist: Apply NBPT With Urea To Prevent Volatilization

BETTY VALLE GEGG-NAEGER
MidAmerica Farmer Grower

MINER, MO.
   Applying nitrogen as urea and preserving its effect was discussed by Dr. Peter Scharf, nutrient management extension specialist with the University of Missouri, at the Regional Corn Meeting here recently.
   He had two main messages for producers: The first is that in a wet year nitrogen is lost, and those losses need to be made up by an increase in sidedress nitrogen application for corn.
   His second message was about additives for fertilizer, and the key ones he touched on are for use on urea: Agrotain and other generics with the same active ingredient, such as N-Fixx and Arborite AG. The active ingredient in all three products is NBPT.
   






 Dr. Peter Scharf, nutrient management extension specialist with the University of Missouri, recently discussed nitrogen loss in wet years and additives  for fertilizer.
 Photo by John LaRose, Jr.














 
 
 
 “It’s really crucial to put those on the urea if you are putting urea on the surface,” Scharf said. “If urea is going to be worked in or irrigated in, that will manage the same problem, but if you leave it on the surface with no treatment, you’re going to lose 25 percent on average.
   “Depending on the weather, the loss can be anywhere from zero to half, and the uncertainty of how much you’re losing is as much of a problem as the fact that you’re losing about a quarter on average,” he added.
   Scharf advocated either getting urea into the soil or treating it with one of the NBPT containing products. There are a few other products out there that may have some benefits. Some research shows yield responses, but protection from the ammonia loss is inconsistent or nonexistent.
   “Two products I am thinking of are NutriSphere-N and NZone which have shown some evidence of benefit, but protection form ammonia loss is not adequate. Ammonia loss is a big deal. So if you’re using them you should still do something else to protect your fields from ammonia loss.”
   Well-managed urea can be a great way to address the first issue Scharf mentioned, loss of nitrogen in wet springs. March and April rains can affect not only any nitrogen fertilizer you’ve applied pre-plant, but also the 50 pounds of nitrate that is sitting there in the soil before you apply any fertilizer, according to Scharf.
   Urea is the biggest nitrogen source in the Delta and it can be applied speedily with a cart, as a topdress on corn; or with a high clearance machine topdress on corn or an airplane topdress.
   “All those application methods mean it’s going to be sitting on the soil surface so, especially early in the season, it’s important to protect it with a volitalization inhibitor that has NBPT in it, which is the Agrotain or N-Fixx or one of the others,” he said.
   “One other great thing about urea is that it does not burn the corn leaves appreciably. The corn may look ugly for a few days, but we’ve had eight studies showing that putting on at a high rate causes very little yield loss. Urea gives you flexibility in terms of timing, and the speed with which it can be applied in season is another great feature. Things that are flexible in timing but are slow just don’t work nearly as well as things that are flexible and fast. So urea with protection on it can be applied anytime up until tassel, and with a variety of machines including some very economical ones, and it’s fast and effective,” he summed.
   There are two things Scharf wants producers to remember: “If you have a wet April do something to replace the soil and pre-nitrogen that you lost; and if you’re putting urea on the surface, make sure to add an NBPT containing product, which is usually going to be Agrotain or one of the generics that have come on the market.” ∆
   BETTY VALLE GEGG-NAEGER: Senior Staff Writer, MidAmerica Farmer Grower
MidAmerica Farm Publications, Inc
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