Purdue University Department of Agronomy

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May 2012
URL: http://www.kingcorn.org/news/timeless/ReplantDecisions.html

Corn Replant Decisions

R.L. (Bob) Nielsen
Agronomy Dept., Purdue Univ.
West Lafayette, IN 47907-2054
Email address: rnielsen at purdue.edu

rappy stands of corn (aka less than desirable) occur somewhere in Indiana every year. Unacceptable stand establishment in some of these fields may eventually require growers to make decisions about replanting. Deciding to replant a crappy stand of corn should be based on a number of criteria, but unfortunately the most common is often the grower's emotion associated with looking out the kitchen window at the damaged field every morning or driving by the field every afternoon taking the kids to baseball practice.

Making a wise decision about the merits of replanting a damaged field of corn requires more than emotions. In fact, I would rather that emotions be taken out of the equation entirely. Toward that end, I developed a replant decision-making worksheet that assists growers and farm managers in making that important replant decision. The worksheet allows you to determine the damaged field's current yield potential (if left untouched), its replant yield potential, and the dollar returns (if any) from replanting the field.

The worksheet is included in a larger overall publication on corn replanting titled "Estimating Yield and Dollar Returns From Corn Replanting". This Purdue Extension publication (AY-264-W) is available as a PDF-formatted download from the Web at http://www.agry.purdue.edu/ext/pubs/AY-264-W.pdf.

Some of the information that is required to complete the worksheet originates from cropping records and history, including the original seeding rate and planting date for the damaged field. Some of the required worksheet inputs are frankly estimates, including what the field would have yielded under "normal" conditions if it had not been damaged and what market price you expect to receive for the grain after harvest. The expected replanting date and replanting costs are also required for the worksheet calculations.

Finally, some information is required for the worksheet calculations from the damaged field itself. You will need an estimate of the surviving plant population that is representative of the damaged areas of the field. Depending on the nature of the crappy stand, you may also need estimates of after-damage stand uniformity and plant defoliation.

I will be the first to admit that it takes some time and patience to complete the replant worksheet; both of which are usually in short supply at the time the decision is being made. Recognize, though, that much of the replanting that occurs every year throughout the state is based primarily on emotion and not on estimates of economic returns. Taking the time to work through the steps of my replanting worksheet will help clarify the economic returns (or losses) to replanting and reduce the influence of emotions in this important crop management decision.

Related reading

Johnson, Bill, Tom Jordan, & Glen Nice. 2010. Methods to Control Volunteer Roundup Ready or Glyphosate-Tolerant Corn in a Corn Replant Situation. Botany & Plant Path. Dept, Purdue Univ. Online at http://www.btny.purdue.edu/WeedScience/2010/VolCorn2010.pdf [URL accessed 2012].

Nielsen, RL (Bob). 2003. Estimating Yield and Dollar Returns From Corn Replanting. Purdue Univ. Cooperative Extension Service publication AY-264-W. Online at http://www.agry.purdue.edu/ext/pubs/AY-264-W.pdf. [URL verified 5/15/06].

Nielsen, R.L. (Bob). 2012. A Recipe for Crappy Stands of Corn. Corny News Network, Purdue Univ. Online at http://www.kingcorn.org/news/timeless/CrappyStands.html [URL accessed May 2012].

Nielsen, Bob and Peter Thomison. 2003. Delayed Planting & Hybrid Maturity Decisions. Purdue Univ. Cooperative Extension Service publication AY-312-W. Online at http://www.agry.purdue.edu/ext/pubs/AY-312-W.pdf. [URL verified 5/15/06].