It’s important to calculate how much nitrogen your soil has before applying more. Below are several ways to do this:

One tool is a University of Minnesota in-season corn nitrogen calculator (pdf) can help you determine whether to sidedress nitrogen at corn’s V5 growth stage or beyond.

Another way to determine supplemental nitrogen rates is by calculating the crop’s nitrogen-removal rate comes from Dupont Pioneer: Calculate residual soil-nitrogen levels by multiplying 0.66 (average pounds of nitrogen removed by 1 bushel of corn) by the number of bushels produced per acre. Then subtract that from the amount of nitrogen applied per acre.

A University of Illinois nitrogen-rate calculator is another tool to estimate the amount of residual nitrogen and determine how much you need to adjust for this year’s application.

A spring soil sample is another way to assess the need of the growing crop to calculate an efficient nitrogen application.

corn nitrogen rate calculator