To add to what Sticker wrote, another option would be winter wheat. As far south as you are, you still have growing season left.
You are a little late for brassicas, even that far south.
If you want a plot that keeps producing for years, plant a good clover blend with wheat or oats as a nurse crop. Fall is an excellent time to plant clover and even more so as you move that far south.
If you want an annual mix with a little more protein, I do a blend of oats, rye, and 2 types of rape–DER and a type of giant rape. Rape obviously won’t reach seed stage, but the protein in the stalks makes it desirable.
Best of luck.
Grouse