All the results aren't in yet. As they would say in the world of politics, they're waiting to tabulate the absentee ballots and determine the final outcome. But Jim Camberato and Bob Nielsen, two Purdue University Extension agronomists, are pretty sure what the final results will show once they've had a chance to review their data in the next few weeks. They're expecting to turn relationships they've seen between nitrogen rates and yields during the season for the past two years in both trials and in real farm fields into more useful N rate recommendations.
The pair of Extension agronomists has conducted as many trials as possible since '06 in an effort to develop a bank on modern nitrogen-response data for adding N on corn in Indiana. Since most of the data was collected nearly two decades ago, they didn’t feel they had a good base to make recommendations for nitrogen rates for Indiana farmers. With nitrogen prices climbing, interest in how to fine-tune rates grew. But as corn prices soared, reluctance to cut rates so far that it might impact yields also increased.
Iowa State University 'houses' a computer program on its Web site called the Nitrogen rate calculator. It was developed with help from agronomists form several states, including Iowa and also Illinois, where Emerson Nafziger, Nielsen's counterpart west of the Indiana border, was very involved in collecting data from trials where nitrogen response was measured, and helping turn those data into a usable tool. With the calculator, you, as the farmer, can enter actual N price per pound, and price of corn per bushel, and learn both what the rate should be in your situation for top agronomic yield, and for best optimum economic yield. Often, there’s about a 20-pound spread, with the rate that makes the most economic sense being some 15-20 pounds under the rate that typically produces top yields.
Data is available for various states in the calculator, including Iowa and Illinois. The program bases recommendations on the battery of test results from the state selected. Until now, Purdue's agronomists haven't felt confident enough about their data to include Indiana results in the calculator program. So if you’re an Indiana farmer and use the program, Nielsen suggests selecting the Illinois databank. Then add 10 to 15 pounds per acre or so to account for typically slightly higher N loss potential and somewhat lower organic matter of most Indiana soils, compared to Illinois soils.
They hope to rectify that situation yet this winter. If all goes well, it's possible that you may be able to call up the calculator, and ask for N recommendations based on Indiana date. Nielsen and Camberato are in the process of determining if they can get the data included in the calculator based upon what they've gathered so far through two years of trials.
Check out the nitrogen rate calculator for yourself at: extension.agron.iastate.edu/soilfertility/nrate/aspx.
Plenty of explanation is provided to make the calculator a useful tool for your farming operation.