Depends what u want..... for example.... if u wanted more natives and not as concerned with Forbs - I'd highly suggest cleaning a field with a 10-12 oz/acre spray of plateau on existing established natives. Yes- even switch (established!!). If weeds are a mess or perennial weeds up before desireables- a post emergent included before natives green up. This will make your stand clean and go nuts. Following year- fire. That's just one of million examples. Can substitute atrazine for plateau on ESTABLISHED grasses. Heck- could do both.
For brome: late fall spraying. Late spring - early summer burning. Also- an early spring spraying. Could do all 3 in reality. Agree with above- except for waterways- it's worthless. And PLEASE don't do what too many guys do and start burning in March for example. All u are doing is clearing a slate for cool season garbage to dominate and go bananas. Drives me insane seeing this!!
Now- when a guy wants Forbs- big change of plans. Plateau tolerant - answers itself (let me know if don't understand). Non-plateau tolerant..... earlier burning, interseeding, mowing super high to cut off weed plant tops to prevent from seeding (for example, this year was a pain with marestail in fields). Ain't gonna kill stuff like marestail or whatever but u wanna keep em from going to seed and promote desireables from mowing, timely spray or burn, etc. if no grasses & want forbs, clethodim & crop oil.
Such a loaded question with dozens of scenarios and answers. U throw out a specific scenario: what's planted, when, how it took, weeds there, how long it's established, goals and pry have 3-4 viable options depending on scenario.