Iowa State University Extension and Outreach

East-Central and Southeast Iowa Crop Information


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June 26, 2006




Will Additional Nitrogen Pay Off?


            There has likely been a lot of nitrogen lost again this spring with the excess rainfall. One thing to keep in mind that not all of the nitrogen has been lost even where the corn is very stunted and yellow in areas that have had saturated soils. Roots cannot grow into water, so plants do not do well with continuous saturation of the soil. Some of the yellowing is just from “wet feet.” A lot of soybean fields are showing this yellowing as well. However, much of the nitrate nitrogen will have been lost by de-nitrification in soils that have been saturated for an extended period of time. Additional nitrogen will likely pay off as long as the corn stand is still there and there is still potential for getting a good yield. An additional 50-60 lb/A of N should be considered on fields that are showing N deficiency symptoms and in fields that have had an extended period of soil saturation. The sooner it is applied the greater the yield response will likely be, but it can pay even up through tasseling. See John Sawyer’s article for more information at


Controlling Tall Weeds in Tall Corn


            Planned postemergence herbicides have not been sprayed in some fields due to the continued wet weather. Drop nozzles will be needed to get good coverage of the weeds and to reduce injury potential to the corn. Roundup can be applied to Roundup Ready 2 corn up to 48” tall with drops. Liberty can be applied up to 36” tall corn with drops. On conventional corn, Impact can be applied up through tasseling, but will not likely give complete control of grass over 3-4” tall and broadleaves over 6-8” tall. For a list of height restrictions on corn herbicides see Mike Owen and Bob Hartzler’s article at






Muscatine Island Research Farm Field Day and 75th Anniversary, Fruitland

June 29

The Muscatine Island Research and Demonstration Farm was founded 75 years ago.  A special field day will include many special events in addition to the traditional field day.  If you have an interest in horticulture, be sure to attend.  Information will appear soon at


Northeast ISU Research Farm Field Day, Nashua

June 30



Field day speakers include:   Ken Pecinovsky, Farm Superintendent, Robert Hartzler, ISU Extension Weed Scientist, Alison Robertson, ISU Extension Plant Pathologist, John Sawyer, ISU Extension Soil Fertility Specialist, Chad Ingels, ISU Extension Program Specialist, and Brian Lang, ISU Extension Agronomist. CCA Credits available for a fee.



If you have any questions, please feel free to contact the Iowa State University Extension Office.

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Last Update: June 26, 2010
Contact: Jim Fawcett

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