One of the more confusing things about wheat is determining the growth stage that the crop is in. Probably one of the most critical growth stages to be aware of is when the wheat moves from the tillering phase into the jointing or stem elongation phase or the Zadoks 30/Feekes 4 stage. Many of our inputs including most fertilizers and herbicides need to be applied at or before this stage of growth.
Why does this matter now?
Ideally, Zadoks 30 (Feekes 4) is the best time to have your nitrogen out since this is when the crop transitions from vegetative growth to reproductive growth. This is also the growth stage when nitrogen use in the plant increases.
The chart of the growth stages is below:
So how do you know which Growth Stage your wheat is in?
The late tillering phases and early stem elongation phases look very similar in the field. Generally, the plants will be standing up and be taller as the wheat enters the stem elongation phase. Splitting the stems and finding the growing point will allow you to be more confident of which stage of growth you are in however.
To do this, take a wheat stem/tiller from your field and split it lengthwise all the way down to the roots. Inside you will find all of the leaves that the plant has developed rolled up and you will find the growing point. If that growing point is at the base of the stem near the roots, you have not entered the stem elongation phase of growth yet. When you see that growing point has moved 1/2-3/4 inches above the roots, the wheat is now in Zadoks 30 (Feekes 4) growth stage or the beginning phase of stem elongation and this is the ideal time to have all nitrogen applied.
I have been looking at several fields across the county over the last two days and little to no wheat has reached the stem elongation phase as of yet. However it will not be long and a significant portion of our crop will be entering this growth stage.
Here some pictures that I have taken over the last couple of days:
This picture is of wheat that has not quite reached the Zadoks 30 (Feekes 4) stage yet. Though difficult to see, the growing point is still at the base of the stem near the roots.
Here the growing point has already moved upwards and the stem has began elongating. This particular field of wheat had already moved past the Zadoks 30 (Feekes 4) growth stage.
If you have any questions about staging your wheat, contact your local extension agent.