I'm looking seriously into the same thing (deer vetch, american joint vetch). I live in north central Kentucky and I'm trying to bridge the gap prior to planting Buck Forage oats. I'm looking to combine buckwheat, aeschynomene, and alyceclover into 2 bottomland plots that are each a little over 1 acre.
I sowed BF oats in these fields last fall and the deer flocked to it. It had been fallow for some time. PH is in the mid 6's. Keep me up to date on your luck with it.