I got a Question, Well Me and another Hunter was talking about if we built a fire on about 20 acres of land, all weeds, would this help the mule deer? Theres gonna be fresh alfalfa planted this spring about 150 acres. Just get tired of seeing the weeds, there about 5-6 feet tall in some places. And we'll have a pumper on site but I don't think it'll go anywhere since the fields are raked.

I have no helpful advise about the deer, but this reminds me of when my dad thought he could stimulate new growth with a controlled burn. Just Dad, and probably too much beer. He got to meet the volunteer fireman of the area when it didn't go as planned. I think it was during a fundraiser, too. Dad always donated a lot to the VFD after that.
Be careful.

Will fire help the mule deer?...highly doubtful. Only on Native range or CRP will that actually come into play. Mule Deer are not the most discriminating of eaters and don't always know the difference between weeds and alfalfa. Funny thing about some weeds is that they are as nutritious as alfalfa.

Since you plan to plant the area to alfalfa, fire is probably a good idea to get some of the residue removed. After the fire, spray the field with Roundup when weed seedlings start to pop up.

If you or the land are enrolled in USDA programs; I strongly suggest that you make sure everything is kosher before you put a plow to the ground. I know of a farmer that lost his gov't payments because he broke new ground.

Talk to the local Natural Resources Conservation Service or Extension Agent. These guys should be able to get you some info.

Good advice about talking to a local NRCS or County Extension Agent. The US Forest Service regularly do "wildlife burns", often funded and/or assisted by the Rocky Mountain Elk Foundation or other wildlife groups. Fire will stimulate new growth in many of the plants that deer, elk, and other wildlife like to eat.

One disadvantage of burning is that some weeds, like Canadian Thistle, can also come in strong after the burn.

Seems like you have a weed patch in the middle of cultivated crop lands. That 20 acres is the only place that you have described where the deer can bed and escape. Burn it and you will lose the bedding areas (if they are using it). Overall, fire can stimulate growth which will benefit mule deer, but I do not see a value in burning an area as described, unless there are other bedding areas close by you have left out of the equation.