Any year would be nice one to get a grain protein premium, or at least avoid the discount, especially in a wet year, says Montana State University Extension Soil Fertility Specialist Clain Jones.
But to produce high grain protein, there must first be enough nitrogen to meet the wheat's growth requirements, he notes. Once yield potential is met or whether factors become limiting to yield, excess nitrogen is used to make protein, says Jones.
With high moisture producing high yields, yet causing potentially high nitrogen leaching losses grain may need an early in-seasons nitrogen application to meet yield requirements, and a late-season nitrogen application to achieve high protein, he believes.
Crop management practices such as selecting varieties with high protein potentials and using legume cover crops, green manure or livestock manure as sources of long-term, late-season nitrogen can improve the chance of getting high protein, Jones explains.
However, because these choices no longer play into this year's harvest, "providing additional nitrogen is the most important management factor to produce high protein," he says.
While nitrogen increases should be addressed now, there will soon be a new MontGuide available explaining the process, released by the MSU Extension Service. To find this publication, go to http://msuextension.org/publications.asp, or call (406) 994-3273 for more information.
Nitrogen provided before heading will most likely improve yields, while nitrogen taken up during and after heading may increase protein, Jones argues.
Nitrogen concentration in the flag-leaf (uppermost leaf of the stem) at heading can be measured to determine whether a late-season nitrogen application will boost protein, he says. According to regional research in Montana, grain protein is likely to increase with a late-season application of nitrogen if the flag-leaf nitrogen concentrate is less than 4.2%.
The lower the flag –leaf nitrogen, the greater the potential response to late-season nitrogen, he reports, but the more nitrogen that will be required to reach high protein.
"Flag-leaf analysis can tell you whether the crop is likely to increase protein content with late-season nitrogen," he says, "but not how much nitrogen to add, or the final protein level."