Evaluating wheat crop conditions going into winter
(Note: The following article is a slightly edited transcript of a short K-State Research and Extension YouTube video produced by Dan Donnert, KSRE videographer. The link to this video is: https://youtu.be/7zL0BQUXLas – Steve Watson, Agronomy eUpdate Editor, and Danielle Comstock, Agronomy Communications Student Intern)
What is the likelihood that the wheat crop in Kansas going to have successful winter survival? What are some of the things that we need to be looking for?
First we need the crown to be well protected. The wheat in Figure 1 below was planted in mid-October. The crown is about one inch below the surface in mid-November, and this is about right. We want the crown very well insulated by the soil. So as long as that crown is insulated, the soil is going to protect it from the winter temperatures and it’s going to increase the likelihood that the crop is going to make it through the winter.
Figure 1. Wheat with crown about one inch below the soil surface, well insulated for winter. Source of all photos: https://youtu.be/7zL0BQUXLas
Some of the problems we might face is with late-planted wheat, for example in south central and southeast Kansas, where planting was delayed in some cases due to too much moisture. Late-planted wheat crop is not going to be as well developed as we’d like. We’d like to see wheat with anywhere from three to five tillers (Figure 2) going into the winter. That is enough development to allow the crop to produce all the antifreeze substances it needs to make it through the winter.
Figure 2. It's best for wheat to have 3 to 5 tillers going into winter.
A crop that was planted late, for any of several reasons, either due to double cropping after soybeans or because planting was delayed due to moisture -- or as in southwest Kansas this year the wheat was mostly planted in time but didn’t come up until mid-November because of lack of moisture – that wheat will be more exposed to the dangers of freezing temperatures.
The wheat in Figure 3 was planted late as a double crop after soybeans. As if mid-November, some of this wheat had not emerged or was just starting to emerge. This is going to delay the whole development of the crop. The wheat in Figure 3 has just put its first leaf out and has not started to tiller yet. This wheat is definitely not as cold hardy as the wheat in Figure 2.
Figure 3. Poorly developed wheat is not yet well prepared to survive the winter.
Another main difference that we have between these two fields (wheat planted on time and wheat planted late) is in root development. The late-planted wheat doesn’t have its secondary root system developed yet. It’s going to take another couple weeks before it even starts to develop secondary roots. So these factors are going to affect its winter survival as well. Where I would be concerned is in southwest Kansas because in many fields, although they were planted in time, the crop has not emerged up to this point and those situations are where we can really see the crop having some problems making it through the winter.
Romulo Lollato, Wheat and Forages Specialist