One of the problems with farms today is so many don't get it, don't let weeds go to seed, whether you mow them, spray them, plow them or hoe them by hand, the only way to control long term is to stop letting them reseed. County here killed some landscaping a few years ago, I talked to them and then they sent out a form for me to sign where I take care of weeds along road between the red and green markers. They haven't sprayed my bushes since, but there are literally miles of roads with noxious weeds that go to seed (and yes, the seeds for thistle blow far and wide) every year. When I was growing up, we had clean fields, but part of that was keeping the fence lines free of weeds, most farmers did this, made it easier for all.
It's probably been 15 years now, but my brother had a golf cart with sprayer on back, I asked him why, he said when he was working on irrigation or saw weeds, he just sprayed them. He added a bit of Roundup occasionally to tank to keep it fresh.. 40 years ago, we walked and carried a shovel to deal with weeds.