Q: Can you talk a little bit about wheat winter injury?
A: The following is from Jeane Falk-Jones area agronomist and co-leader of the Rawlins County Wheat Plot Discussion this past Monday:
There has been a great deal of discussion on the condition of wheat fields throughout NW KS. We have fields ranging form looking pretty rough to looking pretty good! Much of the injury is relating back to the cold weather on November 10-11. It isn’t really so much about the cold snap, as it is about the temperatures leading up to the cold temperatures. Much of October and November had quite warm temperatures and nighttime shows just barely dropping below freezing. At around 40 degrees, the plant starts preparing for winter. The wheat plant begins slowing plant processes and moving sugars around in the plant. This helps the what plant harden off and induce winter hardiness. The catch is that the wheat didn’t have much of a chance to prepare for the cold temperatures. This has caused damage to the crowns of the plant. In some cases, the main stem is damaged and in other cases, there is no damage to tillers of the plant. It is very important to split the plants and look at the crown area to assess the damage. Healthy crowns look crisp and whitish-green. Damaged crowns are yellowish to brown colored with a mushy appearance. It is also important to look at both the main stem and the tillers of the plant. The big question is about the plants that look damaged- not completely healthy and not dead. Those plants, in many cases, are a majority of the field. These plants are the ones that can still go either way. On those plants, look for new tillers and new root growth to see if the plant is promoting new growth. New tiller and root growth is an encouraging sign., It is important to get the new tillers well established as early in the spring as possible. It is also important to remember the last tiller to be put on is the first tiller to be aborted in tough growing conditions. In addition, the damaged plants are more susceptible to other stresses- such as drought, diseases and insects. For diseases, the biggest threat is crown rot. When I visited with Erik DeWolf, the wheat pathologist at K-State, he said crown rot is a big threat to the yields of the winter damaged wheat. There is not a great deal of difference between varieties and crown rot is generally an effect of crown damage and dry growing conditions. It is generally recommended to go ahead and top-dress the wheat and apply herbicides. Applying fertilizer to minimize the contact with top growth(like with steamer bars) may be advised to help minimize stress from the nitrogen burn. For herbicides, it is good to give the wheat coming out of dormancy a chance to have a bit of growth (a couple days of good growing conditions) before applying the herbicides. In addition, weed control as going to be necessary because of thinner wheat strands. This will help minimize weed competition and aid at harvest. Be advised though that applying a herbicide now may greatly reduce the options of re-cropping with a summer crop, in the event of a total loss on the wheat. Finally, the wheat conditions are changing daily. As green-up continues, winter injury is becoming more apparent. I know it is difficult, but patience is helpful on determining a plan with the wheat. And as always, a good rain would be quite a blessing.
