Assessing Wheat Stands for Yield Potential and Nitrogen Application Timing
See how to assess the condition of a wheat field in the spring.
- [Instructor] Growing a good wheat crop starts with high quality seed and timely planting.
But getting wheat planted within the optimum time period is not always possible, and this may result in a stand that is less than desired.
Assessing the stand in the spring can provide information that can be helpful to make decisions about managing that field, determining if there is a high enough yield potential to justify keeping the crop, or how early the field should be topdressed with nitrogen.
To do a stand assessment, take a yard stick and walk across the field to count plants in several different locations.
Lay the stick along the row and count the number of plants in a three foot length.
In fields that did not have much growth the previous fall, counting plants is fairly easy.
Move on to several other places in the field, stopping at random so a good objective sampling of the field is made.
After you have counted in a sufficient number of areas that you have a good representation of the field's condition, determine the average per three foot measurement from all the places you checked.
Then you can use this equation to calculate the number of plants per square foot.
Take the average number in three foot of row and multiply this number by four.
Then divide by the row width in inches.
For example, if the average number per three feet was 48 and your row width is seven inches, you multiply 48 times four and divide by seven.
In this example, we calculate that there are about 27 plants per square foot.
Wheat can compensate for lower plant densities, but if the stand is as low as half the number recommended, it probably isn't worth keeping.
Evaluate how well the plants have tillered or branched out.
Knowing the number of tillers is probably more important than just knowing the number of plants, since not all plants will produce the same number of tillers.
Wheat properly established in the fall will have two to three tillers per plant.
If adequate tillering did not occur in the fall, the field should get an early application of nitrogen.
This will stimulate more tillering on the plants than if topdressing is done later.
Spring tillers are not as productive as fall tillers, but they are more productive than if they weren't there at all.
On fields with an adequate number of tillers, early application is not necessary.
In this case, or in fields with a high tiller count, apply nitrogen at growth stage five just before the stems begin to elongate.
This is also just before the first node of the stem can be seen.
This will minimize excess tillering that can cause weaker stems and provide the nitrogen when the crop can make the most efficient use of it.