Published on Friday, February 3, 2017
I’ve recently had the opportunity to scout a few wheat fields and I wanted to share with you a few updates.
Winter wheat in Missouri experienced incredible fall growth due to milder temperatures and optimum fall soil moisture. This resulted in stand counts of 25 to 35 plants/A. and more tillers per plant than we usually observe at optimum seeding rates. Rather than two to three tillers per plant, I have observed plants with one main stem and four to seven tillers. The good thing about fall tillers is they are more likely to produce grain-bearing heads than spring-developed tillers. As you can see in the photos below, individual plants have seen tremendous leaf growth causing the wheat to have a “brown” cast in the field where individual leaf tips and entire leaves experience frost damage and kill.
Top: A plant at Zadoks 26 growth stage. Bottom: Field view of a “brown cast” field.
Despite some individual leaf damage, wheat plants are doing well and are ready to break dormancy. In the photo below, you can see a cross section of the main stem showing the meristematic tissue at the crown - it is green and viable. This is a good sign as it indicates winter kill has NOT occurred in this field.
I recommend checking wheat stands for tiller counts and over-wintering viability over the next few weeks. Your target tiller count at this time of year should be 75 tillers/sq. ft. Our goal by spring is to be between 75 to 100 tillers/sq. ft. to reach full yield potential.
I collected tissue samples from a field once in December, the results of which are shown below. As you can see, though the levels of phosphorus (P), potassium (K), and sulfur (S) were all sufficient, the nitrogen (N) concentration in the tissue was deficient. In 2015, almost all wheat tissue samples I took in the winter showed excessive N concentrations, but this year I observed early visual signs of N deficiency in many Missouri wheat fields. I believe that despite the fall applications of N many farmers applied, the greater than increased fall plant and tiller growth required more N than was available after a season of high soybean yields.
Typically, I would only recommend N applications in February if there was a need to stimulate tiller growth. In the example of the previously mentioned field, the tiller counts are outstanding so by that factor alone, I would normally postpone additional N applications until the joint growth stage.
However this year, in order to meet the high, early demand for N, I am recommending a February application of 30-0-0-12 (using ammonium sulfate and urea) on this field. We will then apply the remaining N at the joint growth stage in March.
If you have any questions please reach out to myself, your seed advisor, or local dealer.
Author: David Hughes
Categories: Agronomy, Missouri
Tags: Agronomy, Agronomy Update, Wheat, Missouri Agronomy, David Hughes, tiller counts, AgChat, Winter Kill