New nitrogen application calculator and best management practices for the 2009 corn crop

By David Nicolai, University of Minnesota Extension

With substantial increases in the prices of fertilizer nitrogen, farmers are encouraged to re-evaluate their nitrogen rates for corn for the greatest economic return on their investment. A handy, simple, and convenient tool to help Minnesota corn growers arrive at the optimum economic nitrogen rate is the “Corn N Rate Calculator” found on the Iowa State University website at http://extension.agron.iastate.edu/soilfertility/nrate.aspx. The revised and updated CRNC now contains yield data from replicated studies at 128 sites in 25 Minnesota counties from 1990 through 2007.

The calculator is easy to use requiring the user to enter their state, type of fertilizer, price per ton and expected corn price per bushel. The calculator will than calculate the maximum return to nitrogen, the N rate where the economic net return to N application is maximized. Users can also enter multiple fertilizer and corn prices at the same time so that they can view and print a comparison of prices.

More detail listing the appropriate nitrogen, phosphorus and potassium fertilizer guidelines can be found in Fertilizing Corn in Minnesota FO-3790-C Revised 2006, available on-line at: http://www.extension.umn.edu/distribution/cropsystems/DC3790.html

In this era of fluctuating high prices, farmers using N rates provided by the on-line Corn N Rate Calculator coupled with other best management practices for nitrogen will be able to obtain the greatest economic return on their fertilizer N investment.