Farming herbs in South Dakota

We have about 5 acres that is in alfafa right now that is put up for cattle feed. Can it be sold and used for herbs? Also would like to put in 2 acres of herbs that will be compatible in southeast South Dakota and there is a market of buyers out there for it. At this point I plan to get the 2 acres ready, hopefully a crop in this year that can be a first time with mistakes and a profit? Knowledge would be a great help. Tried many places local but not much luck.

The only Alfalfas sold to the herb trade are those from full irrigation, and dairy-grade. While you don't mention irrigation I suspect you have none. Is that correct? That will make a major difference in your crop selections.
The crop of choice for your region is Echinacea angustifolia, which grows best with no irrigation. It is a root crop, requiring potato gear (or equivalent). The flower-heads from the Tagetes varieties of Marigold is used for poultry feeds has also been successfully grown in your region.
Dry-land farming has fewer options. And, predicated on where you farm in South Dakota will dictate which other crops might want to be selected. The second part of that equation is to make sure you don't need different equipment for each crop, but select those which take advantage of your local and regional "Appropriate Technologies" (Canadian term).