Areas of Concern during Dry Harvest Conditions

Be prepared to manage stalk rot, over-dry corn, combine fires this coming harvest season.

Published on: Aug 29, 2012

As harvest draws near, University of Minnesota Extension crops educator Liz Stahl, Worthington, notes several potential areas of concern, due to dry conditions, that farmers may want to watch out for.

They include the following:

-Stalk rots & ear droppage: Drought stress can lead to poor stalk quality and weakened ear shanks. Monitor fields and check corn plants for signs of stalk deterioration or risk of increased ear droppage. An easy way to identify stalk quality issues in a field is to either push on stalks to see if they collapse or bend over, or pinch stalks at the lower internode to see if stalks compress easily. Any fields with stalk quality issues should be targeted for harvest as early as possible.

Be prepared to manage stalk rot, over-dry corn, combine fires this coming harvest season.
Be prepared to manage stalk rot, over-dry corn, combine fires this coming harvest season.

- "Over-Dry" Corn at Harvest: Corn grain moisture levels around 13% were not uncommon by the end of harvest in the dry conditions of southern Minnesota last fall. Corn is normally sold at a 15% moisture content, and clean, good quality corn grain can safely be stored up to six months at a moisture content of 15% with proper aeration. Thus, grain at a moisture content below 15% would be considered "over-dried" unless a lower moisture content was needed for safe longer-term storage.  Selling corn as less than the market moisture content involves loss of water weight that could have been sold at the price of grain.

Low grain moisture at harvest can also lead to more kernel damage and more fines, which in turn can shorten the length of time grain can be safely stored.  If conditions remain warm and dry, monitor grain moisture levels and keep in mind the "costs" of harvesting over-dry corn as you decide on when to start harvesting corn this year.

- Combine and Field Fires: This was a big issue last year due to dry conditions across the region, particularly on gale-force windy days, and could be an issue again this fall.  Mark Hanna at Iowa State University recently published an article listing prevention tips to reduce the risk of combine and field fires.  Keeping things clean, repairing any leaks immediately, checking coolant and oil levels daily, as well as carrying a couple of fire extinguishers and a cell phone in case of emergency are tips to help decrease the risks of a fire this fall.  For further details, see his article at: www.extension.iastate.edu/CropNews/2012/0808hanna2.htm

- Combine Settings for Drought:  Much variability in crop conditions can be seen across the region, between fields, and even within the same field.  Ear size and kernel size will be smaller than normal in many cases, so paying attention to combine settings will be as important as ever this year.  For soybeans, plants may be shorter and seed size smaller than normal.  Mark Hanna at Iowa State University discusses some good tips and reminders regarding "Combine Settings for Drought" at:  www.extension.iastate.edu/CropNews/2012/0808hanna.htm

- Nitrogen Carryover Potential:  In a year following a drought, there is potential for significant levels of residual nitrate nitrogen to remain in the soil profile.  Where conditions were dry in 2012, soil sampling for nitrate nitrogen to a depth of 24 inches should be very useful in deciding how much nitrogen to apply for the 2013 corn crop if the previous crop was corn.  The test is also useful if the previous crop was corn or soybeans and manure was applied.  This test should not be used, however, following alfalfa.  For this test, samples should be collected from a 6 to 24 inch depth in addition to the standard 0 to 6 inch depth.  Samples can also be collected from a 0 to 24 inch depth and analyzed for nitrate nitrogen. 

In western Minnesota, samples for nitrate nitrogen can be collected in the fall or spring, while in south-central, southeastern, and east-central Minnesota, samples should only be taken in the spring before planting.  The amount of nitrogen to apply can then be calculated after adjusting for the amount of nitrate nitrogen likely to be available for the 2013 corn crop.  The U-M Extension publication, "Fertilizer Guidelines for Agronomic Crops in Minnesota" describes the amount of residual N credit to be given based on the amount of nitrate nitrogen in the soil and region of the state.

This publication can be found at www.extension.umn.edu/nutrient-management/Docs/BU-06240-S-1.pdf