April's Ag Advice By April Borders Our winter weather has been unpredictable this year and so far we have been enjoying some pretty nice conditions. This might be nice for us but it can cause problems in some of our fields. We have not had a snow cover to protect our winter wheat crop and the next couple of weeks will be critical when looking at the plants ability to overwinter. The spring can bring weather that favors multiple cycles of freezing and thawing.
Freezing and thawing causes heaving, where the crowns and roots of wheat plants are pushed up and out of the ground. These plants generally don't show stress until the temperatures warm and they begin to grow. By about mid-March, growers begin to see these plants turn color and report that the wheat is "going backwards". This is because it generally takes several weeks for the heaved plants to show water stress and die.
The wheat may have a difficult time starting to re-grow this spring so you need to be out checking for problems. Hopefully some nitrogen was applied in the fall at planting and the wheat seed was planted at the correct depth. Planting at the proper depth will help against heaving and the nitrogen applied last fall will supply adequate nutrition as the plants begin to re-grow this spring.
In wheat, nitrogen serves two important functions. Nitrogen fertilizer may be used to manipulate the population (increase tiller number) as well as supply nutritional needs of the crop to produce protein. So, wheat tiller number is an important indicator of nitrogen application timing.
Research has shown that if tiller number is greater than 70 per square foot it may be beneficial to delay nitrogen application until just prior to jointing. The advantage of a delayed nitrogen application is an increase in nitrogen use efficiency and a potential yield increase. However if tiller number is less than 70 per square foot it is recommended to apply nitrogen at green-up in order to increase the effective plant population.
Remember that the wheat plants must replenish its root system in the spring and until these new roots are developed, little nutrition is taken up by the plant. It is during the time when the plants begin to re-grow and new roots become functional that the wheat looks its worst. Given time and warmer weather, the wheat will begin to improve in condition. So watch your wheat fields and note any fields that are not "greening-up" as expected.