ISSUE 5   June 10, 2010


Many growers are requesting information about yield and/or protein enhancement in spring wheat. Most spring wheat in the state varies from about 5-leaf to boot stages. For spring wheat stages before boot, stream-bar applications of N still have the potential to increase yield if the season allows. Stream-bar applications must have about Ĺ rain after application in one event for the N to be taken up by roots. If stream-bar applications are made and it doesnít rain, the results will be less. Once the spring wheat enters boot stage, all significant yield enhancement possibilities with more N are gone. At this stage, tillers are made, number of heads and spikelets are determined. There is nothing more that N can do in yield enhancement except perhaps increasing kernel size; but that increase is very small and probably not worth the expense by itself. Any N added at boot stage or beyond will go into producing more grain protein. Stream-bar N at boot stage can work, but it needs rain to work. A more consistent application is the post-anthesis broadcast application. Research that went into the post-anthesis broadcast application is available on my website (  look at choices on left side of webpage).

The recipe is:

  • Wait until flowering is nearly 100% complete. You might see a few stray anthers here and there, but the majority of wheat berries will squeeze out clear liquid. If the berries are milky, itís too late for protein enhancement. Absolutely do not apply during flowering.
  • Blend together 10 gal/acre 28% + 10 gal/acre water.
  • Apply broadcast (NOT stream-bar) in the cool of the day. Ground equipment probably because of the 20 gal/acre total rate. Expect some leaf burn, but the research shows that flag leaf burning after anthesis did not result in yield losses.
  • Expect from Ĺ % to 1% increase in protein.
  • Also- Do not use low rates (1-3 gal/acre) of slow release liquid materials. Research (also on my webpage) shows that these rates are not enough to increase protein similar to the recommended recipe explained above. If you use these slow release N materials at similar N rates (30 lb N/acre) you will achieve the protein increases suggested for the recommended recipe.
  • Dave Franzen
    NDSU Extension Soil Specialist

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