sealPurdue News

March 17, 2003

Topdressing could cost top dollar this year

WEST LAFAYETTE, Ind. – It's time for farmers to topdress winter wheat, but the cost of doing it might give them sticker shock, said one Purdue University expert.

Ellsworth Christmas, a Cooperative Extension Service crop specialist, said that while most farmers aren't facing problems with snow, they are dealing with high nitrogen costs.

"Nitrogen will be expensive, at least for a while," he said. "But if you want to produce a crop you're going to have to add nitrogen."

Because of the high costs, Christmas suggested evaluating wheat stands to determine their needs. Some farmers may choose to split applications in order to spread out the cost, he said, but it's important that at least half of the nitrogen is on the crop at dormancy break. He estimated that dormancy break this year will be around March 20.

Charles Mansfield, an Extension crop specialist based in Vincennes, Ind., said most of the farmers in the southern half of the state were able to topdress their wheat in February because of a break in the weather. He said it's not uncommon for farmers in the southern half of the state to get to the fields before their northern counterparts.

Other than the price concerns, Christmas said this should be an average year for topdressing.

He recommends farmers apply 75-100 pounds of nitrogen for topdressing, assuming they applied 25-30 pounds at planting and the wheat stand is good. Christmas described a good stand as one with 30-40 plants per square foot with good fall tillering. Tillering occurs when buds at the base of a wheat plant develop into an erect shoot, usually when plants are 6-8 inches tall.

It's important to take into consideration historical yields before applying nitrogen.

"Apply 75 pounds if the past yields were average and more if they were above average. However, don't apply more than 50 pounds if the field had low yields last harvest or if it has a poor stand now," Christmas said.

Mansfield said farmers who haven't purchased nitrogen might be better off using 28 percent liquid nitrogen instead of urea this year because of the cost. Christmas also suggested using 28 percent. But streamer bars are a must with liquid nitrogen, he said.

"Getting too much liquid nitrogen on the wheat leaves can lead to fertilizer burn and a rhizoctonia infection," Christmas said.

Other nitrogen sources for topdressing include urea, ammonium nitrate and ammonium sulfate.

Even though it's the least expensive, urea can volatize on warm, dry days and escape into the atmosphere as ammonia gas.

"Liquid nitrogen out of a streamer bar is actually more efficient," Christmas said. "Potential losses from urea can be fairly high on warm days."

One thing is sure, if farmers haven't purchased their nitrogen, they'll need to shop around for the best price.

Steve Hawkins, assistant director of the Purdue Agricultural Centers, said nitrogen costs have risen tremendously in the past few weeks.

"When I checked, liquid nitrogen was up $60 to $70 per ton, and urea and nitrate had risen $60 to $90 per ton," he said. "And, prices are still creeping up."

Alan Miller, a farm management specialist, found the same thing when he started surveying fertilizer prices in early March. Miller said all types of nitrogen have increased by as much as 40 percent to 50 percent since the beginning of January.

"In early January urea was at $190 to $205 per ton; prices for March were near $290 per ton," he said. Hawkins said he has found similar increases in prices for all nitrogen sources.

"Which kind to use is kind of a question mark right now," he said. "It depends on the field and the farmer."

Writer: Kay Hostetler, (765) 494-6682,

Sources: Ellsworth Christmas, (765) 494-6373,

Charles Mansfield, (812) 888-4311,

Alan Miller, (765) 494-4203,

Steve Hawkins, (765) 494-8370,

Ag Communications: (765) 494-2722; Beth Forbes,;

Related Web site:
Extension publication about winter wheat production

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