Low soybean yields?

An earlier entry in this blog this fall, I talked about Charcoal Rot and how it might be affecting yield without us knowing it. There could be another reason for lower-than-expected yields in soybean fields and that would be chemical damage from late applications of herbicide for waterhemp control. I had the opportunity to weigh a comparison of beans that were sprayed late with a contact-type herbicide for waterhemp control vs. non-sprayed beans. The results:
Non-sprayed soybeans - 58.83 bu/a
Sprayed soybeans        - 40.10 bu/a

I don't think you will see that kind of yield loss of 18 bu/a everywhere and maybe no yield loss at all but if you have a bean field that just doesn't yield up, it might not be the variety, it might not be charcoal rot, it might be late-herbicide applications.