I have done food plots for a number of years. If I am doing a fall plot I keep it simple. First I don't ever plant a seed that has a deer on the package. I make my own mixes because you really aren't suppose to plant small seeds with large seeds. Here is my favorite fall plots.
Wheat
Oats (sometimes)
Crimson Clover
Radish
turnips
I might throw in some other annual clovers such as arrowleaf.
I very much dislike ladino clover. I base this off my experience at the plot I can see from my house. Planted ladino clover, we saw the occasional deer, it was a big deal when we did. Two years ago I took half that plot (its an acre plot) and planted alfalfa. Oh my what a difference. Went from seeing the occasional deer to seeing multiple deer daily. Got a buddy with deeper pockets than me and he plants forage soybeans every year, they work excellent.
Like
@EricS stated earlier, planting fall plots can be frustrating. Plant it and it doesn't rain. Happened to me last year. Also planted during a drought in the fall, didn't come up for a month but by Thanksgiving it was lush and green and oh boy were the deer pounding it.
In addition to my deer plots I put in two dove plots. Brown top millet and sun flowers. Rotate them annually. Once dove is done I disc/till it and plant wheat just so there is something on the ground. This year I put up a couple of cameras (these fields are in more open areas), I was surprised at the night time activity of deer feeding on them.
Maybe I am stupid or lucky or both, but I have never done a soil test. I try to lime every year and put fertilizer down when I seed. That's about it. All the experts recommend soil test. I am just too lazy.