Is there a place for burning in hay-field renovation?

Here in dry but irrigated southern Idaho, we're trying to improve two and a half acres of timothy and weeds. Have planted a mix, of which the meadow brome took, and planted half to orchard grass which came on nicely after the seed passed a winter. Trying to kill off cheat grass, foxtail, and Medusa head. Finally sprayed the whole place with  2-4D for the broadleaves, but these noxious grasses are more of a problem. We'll make hay for the 1st time in a week or so.

 

My question--in places there is much thatch and when I burn cheatgrass patches, fire easily spreads under the timothy to burn the dry thatch. If I let this occur, will it kill the timothy? More generally, I know that in natural grasslands, fire is often a good thing. I am tempted to burn the whole pasture this fall...does anyone do this when trying to improve a hayfield?

 

Thanks for any thoughts.

Is there a place for burning in hay-field renovation?