I didn't address weed control. I don't know how large an area we are talking about. Small areas can be covered with black plastic to control weeds to avoid chemicals. I do this for my mother's garden plot to kill off the winter/early spring weeds.
@JSmetalcraft, I avoid broad leaf killers like 2-4D due to having a small vineyard on our 56 acres. Many of the 2-4D type chemicals are deadly to grape vines and I suffer damage every year from nearby farms that spray stuff like dicamba/2-4D mixes. I've discovered with growing a vineyard that these chemicals can carry some distance (ie, a mile). I do use Glyphosate products, but generally only on the fence rows and am careful with it's application. Mechanical weed control is always an option, but don't know of way to do this with such crops as barley.
PS. Not sure how a per-emergence chemical such as preen would work with barley. Check the labeling for Preen as I think there's a warning about using it on stuff you are going to consume.
