March 06, 2018
Decision Time on Late Emerging Winter Wheat
Drought has had a tight grip on the great plains during the fall and winter months. Now that some rainfall has occurred in some areas and in some cases, winter wheat is now emerging, growers are curious on what they should expect. While we cannot predict what mother--nature will throw our way here are a few things to consider.
One of the first things you will need to understand is when wheat imbibed water to start germination. This is extremely important because southern areas may not have time to vernalize depending on when seeds first swelled. From the time the seed swells most winter varieties will need 4-6 weeks of chilling temperatures 50 degrees or less to vernalize. For example, if your seed swelled on February 10, and average lows will be at 50 degrees or less, wheat will vernalize in 4-5 weeks depending on variety. There are differences in vernalization requirements by variety. In general, later maturing wheat will have greater chilling requirements. Check with your seed supplier to find out if information is available on variety vernalization needs.
Second, what type of fertility and moisture is available? Plants emerging in late winter will have minimal root systems and will not be able to extract deep soil moisture or harvest nutrients. Surface moisture and adequate fertility will be necessary to sustain good growth. If fertilizer is not on yet, it needs to be applied immediately and rainfall imminent to activate the fertilizer. If rainfall is not imminent and fertility is not already present, applying more N may or may not help wheat yield.
Third, do you have a weed problem? If you normally have problems with early emerging summer weeds such as sunflower, kochia, and Russian thistle, preharvest herbicides may be necessary. Late or slow emerging wheat will have open canopies and give summer weeds a chance to become a problem. If you historically have clean fields summer weeds may not be an issue. I recommend not using a long residual herbicide because it may limit your future cropping options should commodity dynamics change.
Fourth, price has rallied in recent days and pricing opportunities may be available. If the stars are aligned, and you believe you still have an opportunity to raise a good crop, check with your local grain elevator to see what price you can lock in. This will help you decide on other management decisions, such as fertilizer and herbicide application.
Finally, what kind of yield should I expect if conditions are favorable thru harvest? Data from Kansas State University suggests wheat that emerges after January 1 will yield 40-60% less than a normal crop. Last year we witnessed very good yields from wheat that came up in February in the Texas Panhandle however, moisture was plentiful and the spring was cool. In fields with good fertility 50 plus bushel wheat was harvested.
In summary consider 4 things. Vernalization time, available moisture and fertility, weeds and price opportunities. Call your WestBred representative or seed supplier for more information.