Thursday, July 30, 2009

Low Test Weight in Wheat

As wheat harvest is finally getting into full swing we are hearing scattered reports of low weight and subsequently significant dockage. As these questions arise there are a few factors to consider that may be causing the low test weights.
  1. Genetics: There is a wide range in test weight among the common wheat varieties grown in WI. In a "good" year these differences may not appear significant however in a "bad" year these differences can cost growers significant dollars. The University of Wisconsin Variety Test Program not only provides growers with yield information, but we also report test weight differences. Our variety trial results will be published in the next two weeks. Go to for these results.
  2. Weather: The wetting and drying action of frequent rainfalls on dry wheat can drop test weight quickly. Thus timeliness of harvest is critical. Wheat can also swell following a rainfall and remain swollen even after the grain has dried back down. This increased kernel size displaces space and leads to lowered test weight.
  3. Thin stands: Thin stands due to winterkill in parts of WI have led to late tillering, green stems and immature heads in the field. This may be causing a resource allocation issue in some fields (e.g. some photosynthates maybe going to growth instead of grain fill). If possible avoid these parts of the field if you are experiencing low test weight.