Recent studies show Y-drop and coulter-applied UAN (urea-ammonium nitrate) outperform broadcast urea as a sidedress nitrogen option for corn. The comparison is not even close.
Farmers contemplating nitrogen form and placement this month or next may want to check out the Iowa Soybean Association (ISA) On-Farm Network replicated strip trial results.
“This is really good data for farmers trying to decide the best nitrogen-management options,” says Matt Hoffman, an ISA regional agronomist based in Ankeny, Iowa. “I think it’s relevant for much of the Midwest.”
More nitrogen will likely be sidedressed on corn since less was applied last fall and before planting, agronomy experts say. The right in-season application choice could mean additional revenue and possibly the difference between profit or loss as corn prices hover around breakeven.
Applying liquid UAN on corn with Y-drops last year averaged $34 more per acre compared to broadcast urea, according to multiple replicated strip trials. Research shows coulter-applied UAN bested broadcast urea by more than $30 per acre on average.
“You don’t come across this type of data a lot where it’s so cut and dry,” Hoffman says.
Profit figures were based on yield responses, corn at $3.75 per bushel and nitrogen at 40 cents per pound.
Nitrogen studies were shared with farmers during the ISA Farmer Research Tour earlier this year. ISA research teams--Analytics, On-Farm Network and Environmental Programs and Services--provided overviews of projects and research findings from 2018 during daylong events in three Iowa cities.
ISA Research conducts unbiased agronomic and environmental studies and programming. It includes corn research, which is financed by industry partners and other sources, not the soybean checkoff. John Deere sponsored the nitrogen form and placement trials.
“Soybean farmers raise corn, too,” Hoffman says. “These trials are the best ways to hone nitrogen application and rates so growers can be more profitable.
“I anticipate more nitrogen being applied after emergence since the late harvest, early freeze and wet spring prevented a lot of planned applications,” he adds.
Four nitrogen form and placement trial participants applied 70 pounds per acre, or half of the total, before planting. Anhydrous ammonia was incorporated in three of the four trials, and 32% UAN, a solution of urea and ammonium nitrate in water, was applied in the other.
The rest of the nitrogen was sidedressed when corn was in the V4 to V8 stage. The replicated strip trials compared UAN applied with coulters and Y-drops, and broadcast urea with Agrotain, a dry form of nitrogen fertilizer with an inhibitor to reduce volatilization. In one replicated strip trial, 60 pounds of nitrogen was sidedressed.
Coulter-applied UAN outyielded broadcast urea ranging from more than 5 bushels to nearly 17 bushels per acre.
UAN applied via Y-drops bettered coulters ranging from less than 1 bushel to 8.5 bushels per acre. Three out of the four trials were statistically significant.
“Performance and profit potential may change a little based on individual costs, but our data shows UAN applied with coulters or Y-drops will be better than urea,” Hoffman says.
Nutrient availability to plants and less loss after application are the primary reasons.
Urea tends to be volatile even with an inhibitor. Y-drops put fertilizer at the base of plants and works into the root zone with rainfall. Coulters incorporate UAN in the middle of rows.
Scientific literature indicates broadcast UAN performs similarly to broadcast urea. Incorporating nitrogen or applying in a narrow band provides the best return on investment, ISA agronomists agree.
Denny Friest, of Radcliffe, Iowa, is a big believer in sidedressing corn with UAN utilizing Y-drop attachments on his Hagie sprayer. The grain and livestock producer conducted a nitrogen form and placement trial.
Friest says he understands the right time, place, source and rate of nitrogen to apply for optimal returns and to help the environment. He credits the nearly two decades of research with ISA’s On-Farm Network.
“Eighteen years of data helps me better manage nitrogen,” Friest explains. “My goal is to put on the bare minimum of nitrogen I need in the spring. There’s less leaching and better performance.”
He typically applies 105 or 135 pounds per acre of anhydrous ammonia before planting corn, the lesser amount for corn following soybeans.
Friest follows up with another 30 to 50 pounds per acre of 32% UAN sometime in June, but it can be applied right up until tasseling. The goal is 225-bushel-per-acre corn or better, he says.
Y-drops are Friest’s sidedress method of choice the past five years.
“It gives us a larger window for application,” he says. “There’s more moisture at the base of the plant where the fertilizer is applied, so it gets to the roots. A coulter goes between the rows, and roots have to get to the nitrogen.”
GIVE AND TAKE
Studies show broadcast urea may be a less profitable corn sidedress option, but it is the fastest. Applicators can cover 110 acres per hour on average.
A sprayer with Y-drops can click off an average of 80 acres per hour, research shows. A 12-row toolbar with coulters is typical, Hoffman says, covering about 25 acres per hour.
“I recommend V5 as the earliest to sidedress with Y-drops, otherwise hoses can whip around and even get outside of rows,” Hoffman says. “V4 was perfect for coulter operations in these trials.”
ISA director Rolland Schnell plans to broadcast urea on emerged corn this year despite recent findings. Time and equipment limitations are the reasons.
But, that could change if research continues to indicate UAN is financially better.
“I’m not ready to make the jump yet, but I’ll continue to look at it,” Schnell says.
ISA On-Farm Network director Scott Nelson urges farmers to add urease inhibitors this year given early wet weather. The cost is usually about 5 cents per pound.
Nelson expects many farmers to use different nitrogen sources than usual since fall and spring anhydrous applications were a challenge.
“Agrotain or some form of inhibitor (N-Serve, Instinct Centuro, to name a few) will be critical to avoid loss and nitrogen stress,” he says.
Nutrient stewardship and improving water quality is important to Friest.
The hypoxia problem, or oxygen-depleted dead zone, in the Gulf of Mexico continues to be an issue, he says. So does keeping drinking water supplies safe.
Friest says agriculture is stepping up to reduce nitrogen and phosphorus runoff that’s part of the problem. But, more action is needed to prevent possible onerous regulations.
“Farmers really need to show people we’re properly managing inputs,” Friest says. “We’re part of the problem, and we have to be part of the solution.
”ISA replicated strip trials last year comparing different nitrogen rates for corn after soybeans showed 172 pounds per acre provided the best economic return. For corn on corn, it was 176 pounds per acre.
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