New nitrogen rate calculator is available

Thursday, November 1, 2012

New nitrogen rate calculator is available

A newly developed Corn Nitrogen Rate Calculator is now available through the operation of Iowa State University (ISU) Extension and Outreach and the Iowa Department of Agriculture and Land Stewardship.

The calculator to be used to aid farmers in finding the maximum return to nitrogen fertilizer applications and the most profitable application rate for their farm can be found at

Iowa Agricultural Secretary Bill Northey said the online tool will be rapidly updated to allow for changing hybrid genetics, rotations and climatic conditions.

The Iowa database in the calculator was updated in 2012 with 2011 response data and now contains 214 trials for corn following soybean and 111 trials for corn following corn.

"Having adequate nitrogen available is critical for corn production, but given the high prices for fertilizer it is important farmers determine the right amount that is needed on their crops," Northey said.

The calculator can be used for both corn and soybean rotations and corn-on-corn operations and allows farmers to compare up to five price ratios - pricing options for nitrogen and corn.

A statewide real-time soil temperature data map is maintained by ISU Extension and Outreach at and can be used by ag retailers and farmers to determine when fall nitrogen applications are appropriate.