With the price of nitrogen (N) as volatile as corn prices, knowing your N input costs is more than essential. Online N calculators and budget estimators on university websites can help budget N inputs and application rates.

“I look at them closely,” says Ed Winkle, Martinsville, OH, grower who locked in fertilizer at prices two-thirds of what they were in early March. At that time, UAN 28% was priced at 65¢/lb., about the same as UAN 32%, according to some Corn Belt cooperatives. Along with those jaw-dropping prices, anhydrous ammonia (82% N), was about 45¢/lb., while urea 45% was around 55¢/lb.

Winkle pushes for 190-200 bu., so savings for applications of about 200 lbs. N/acre add up quickly at 20¢/lb. And if half the N applied in midseason can boost yields 10 bu./acre, that’s an added $60/acre for corn priced at $6/bu.

Using the Ohio State University crop production budget Excel spreadsheet, applying 200 lbs. of 28% N to generate a 200-bu. yield would produce an N cost of about $137/acre at the 65¢ cost. Drop that price to 40¢ and the cost drops to about $90/acre.

Iowa State University’s popular N calculator (http://extension.agron.iastate.edu/soilfertility/nrate.aspx) enables users to gauge their N cost over much of the Corn Belt.

In early March, the Ohio site using a $7/bu. price for continuous corn showed these readings for using UAN 28% N: a maximum return to N (MRTN) rate of 200 lbs. N/acre (about 700 lbs./acre applied); a profitable N rate range of 189-212 lbs.; a $467/acre net return to N at MRTN; a 99% of maximum yield at MRTN; and an overall N cost for the MRTN rate of $130/acre.

That compared to about $130/acre for 625 lbs. of UAN 32% applied, $114 for 460 lbs. of urea 45 and $98/acre for 266 lbs. of anhydrous.