Harvest Issues


The 2015 growing season was wet and cool.  Most of Iowa averaged 1-2 degrees below normal temperatures, and all but the Northeast Crop District received 2 -10 inches above normal rainfall.  September is forecast to be on average above normal temperature and continuing above normal rainfall.  These conditions produced very high yield potential at the start of September, but there are many instances of disease, and premature death in both corn and soybeans after Labor Day. As signified by yellowing, corn ran out of nitrogen in many places.  While yield is determined over the full season, crop quality is often established by conditions at the very end of the growing season.

Premature and irregular death in corn will retard kernel fill, which in turn will reduce the test weight from what it would have been with completely filled kernels.  Some yield will be lost, but more importantly, field dry-down and storage properties will not be as good as they might have been.  Test weight of 54-55 lb/bu may be high this year, when a month ago my expectation was around 58-59 lb/bu.  If wet and humid weather persists, regardless of temperature, expect wetter than normal corn at harvest.  Stalk strength is not good in many cases, which requires early harvest to prevent field loss.  The net result is a high yielding crop that will require artificial drying and may not have good long-term storage properties.

It seems like a broken record...weather changes have shifted expectations of new crop corn quality. Three weeks ago, somewhat wetter corn than normal but high quality was the forecast. It is clear that the wetter part will come true; early harvest moistures are generally coming in at 18 – 22 percent, which is above average but not high enough to cause severe complications in drying. Field dry down is probably nearly over so do not expect much change in moisture from here on. Overall quality has been put at risk however, in some areas. The mid-September frost in far northern Iowa caused more reduction in grain fill than was previously thought. This is showing up as lower test weight. However, the southern half of Iowa has had extreme rains in late September into October. This will raise the chances of field molds, primarily Gibberellic, but Fusarium may also be present. Both of these fungi produce toxins.

  • Update on 2014 Crop Quality - By Charles Hurburgh, Department of Ag and Biosystems Engineering, http://www.extension.iastate.edu/CropNews/2014/1015Hurburgh.htm
  • Recent issues with biotech events not approved in some world markets have renewed the need for maintaining required management (stewardship) of biotech grains. As a producer, the most important step in a controlled-market stewardship chain is the initial delivery from the farm to the correct first point of sale. Taking this step protects the continued availability of upgraded traits at a pace faster than otherwise might be allowed.

In 2013, while half of the Iowa’s corn crop was planted by mid-May, planting spread out over about two months, so there were various stages of maturity, often in the same field. Some fields were replanted more than once and as a result pollinated in August. Combine that with the heat wave that withered much of the state late in the growing season and you end up with a crop characterized by inconsistency. Corn yield and grain moisture varied widely across Iowa during harvest this fall. The key thing for a grower was to think about corn moisture levels, drying and storage costs. Iowa farmers who don’t emphasize good grain storage practices this fall will pay for it in the spring, when they find the corn they harvested contaminated with unusual amounts of mold. Uneven quality and maturity in this year’s corn harvest means grain storage management will take on even greater importance than in previous years. Aflatoxin was significantly lower than in the 2012 crop. The soybeans in the pods were smaller than normal this year. Soybeans are small but will be dry, except those fields that were planted quite late. Meetings were held in North Central Iowa to help farmers respond to late harvest, lower grain prices. Extension specialists discussed crop maturity, crop drying and potential effects of an early frost.