Rolling wheat and barley after emergence
I have had a few questions come in regarding the timeline of rolling wheat and barley after emergence. There are a couple of factors to keep in mind regarding this. First, do not roll crops that are just emerging. The first leaf that is emerging from the soil is the coleoptile. This leaf is a specialized leaf that helps the plant push through the soil and emerge.
If you roll during this period, you risk damaging that specialized leaf and impacting emergence, or worse, causing plant death due to inability to emerge. Wait until the 1-2 leaf stage to roll. Second, only roll when conditions are dry and soil won’t stick to your roller. If you find you are getting some mud sticking, stop. That mud will grab onto seedlings and rip them from the soil quite easily. This is a sure-fire way to reduce your plant count. Finally, avoid rolling after the 3-4 leaf stage. After this point, your risk too much damage to the growing crop and developing stems or heads. You may also risk increasing tiller numbers.
In summary: only consider rolling between the 2-4 leaf stage and only the soil is suitably dry
As far as I am aware, there are no studies looking specifically into timing of rolling cereals and effects on yield. If you have experience beyond what is mentioned here, please feel free to reach out to me!