Published Mar 3, 2015

RESEARCH REPORT: Side-dressing corn following a winter rye cover crop–Update 2014

By Stefan Gailans

For a few years now, some of our farmers have been curious about nitrogen fertilizer rates to corn following a winter cereal rye cover crop. This past December, Practical Farmers of Iowa released an updated research report of a study that investigated this issue entitled, Side-dressing corn following a winter rye cover crop–Update 2014.

Over the past five years, three farmers, Rob Stout near West Chester; Tim Smith near Eagle Grove; and Jeremy Gustafson near Boone, grew corn following a winter cereal rye cover crop with a LOW and HIGH nitrogen rate. They wanted to know whether corn needed more N fertilizer than “normal” when grown after a cover crop.


Rob Stout

tim smith photo

Tim Smith

Ralph Storm flies on cover crops Oct 27 021

Jeremy Gustafson








Among the key findings:

  • In only one of six site-years did the high side-dress N rate result in greater corn yields.
  • In most cases, by not applying the high N rate the cooperators nearly recouped the cost of establishing the cover crop with savings in N fertilizer.

This project is supported in part by the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation; Walton Family Foundation; NCR-SARE; and in partnership with the Iowa Learning Farms. For more information on this study, contact Stefan Gailans at

The full report can be found here.