Good short list but the leeks and garlic are not really going to do any soil building. I would add Rape to that list.
My short list so far is:
Clover(what variety though?)
Marco Banks wrote:Travis,
Have you watched any of Gabe Browne's videos? He farms in Bismark ND, close to you. He does a bunch of good stuff with cover crops. If you YouTube him, you'll find all sorts of presentations he's done to farmers all over the country. In his powerpoint presentation, he's got a list of the cover crops he uses. If you freeze the video at that point, you could just write down the names of the crops he's using as a starting point.
He always says, "Don't write this down, as this is what we use in our area. You'll have to find what works best for your area." Well -- OK. But using his list in your first attempt would seem to be smart.
Once you click on his videos and watch a few of them, YouTube will bring up a bunch of other guys who do cover-cropping as well. There is some guy from Ohio who is highly regarded. Ohio's climate might be more similar to yours that North Dakota's climate.
Anyhow, I'd start there if I were you. Gabe is entertaining and very intelligent. He knows what he's talking about.