I am very weed tolerant, but Marstail is one of the most difficult noxious weeds to get a handle on. If you mow too early, it will flower again below your mower height and go to seed. If you wait too late to mow and it goes to seed, you have an even bigger problem. Even if you mow at the right time so it doesn't go to seed, it can sprout the next year from the root system. Gly won't touch it as it is naturally resistant. You can get some limited control with 24D Amine or Ester if you get it when it is young in the spring, but it is limited and you have to wait after using it to plant many crops.
What worked for me was to do a burn down in the spring with a Liberty generic (I think mine was interline) followed by planting a smother crop of buckwheat or buckwheat mixed with sunn hemp. Then burn down with Liberty again in the fall before planting a fall mix. Marestail is not a cool season weed and does not interfere with the fall crop, but it helps the following spring.
I don't worry about a healthy mix of weeds, but when a single noxious weed dominates a field it is a problem. Using gly makes the problem worse. It kills other weeds, some of which are great deer food, and favors Marestail.
Thanks,
Jack