I've been interested in Native American agriculture and subsistence habits more generally since I hit on the idea that they could solve the ecological koan I've been puzzling over for the last six or so months: how can we create landscapes that produce tons of diverse and satisfying foods, and at the same time meet the needs of our nature creatures? Native peoples solved this problem - they maintained a careful balance of wild spaces and cultivated spaces, so that every creature had its place. When the Indian population was decimated by diseases, the ecosystem became a cornucopia of mast, bison, passenger pigeons, and salmon. If the same thing were to happen now, America would just become a patch of monotonous invasives. So obviously there was something worth learning about and imitating there.
Carol Deppe pointed me to this book in "The Resilient Gardener," and I hoped to get some clues here. To that end, there is not much. The Hidatsa either planted or tended patches of serviceberry and chokecherry near their villages. And they harvested a few foods from the vast prairie surrounding the village (bison, elk, and wild turnips). Their chief subsistence is just what you think Native American agriculture would produce: the Three Sisters.
There are a few surprises. BBW doesn't grow the Sisters in the milpa system they are nearly always described in. Corn and beans grow in alternating rows several feet apart, and squashes (and sunflowers) grow in their own patches. There is no mention of companion or successional planting, just a two-year fallow period if yields start to get too low. What's most surprising is how monotonous the Hidatsa diet sounds. Aside from roast meat and green corn, everything is a stew. Stews are made from corn (one of 9 varieties), beans (one of 5 varieties), and squash (only one kind), green or ripe, seasoned with some bison fat and alkali salts (obtained from springs or wood/cob ash). Compared to Sophie Coe's description of pre-Columbian Aztec cuisine in "America's First Cuisines," the Hidatsa sound dreadfully dull. The only thing approaching "greens" mentioned in the book are dried squash blossoms!
The thing that Carol Deppe took away from the book is the technique of drying summer squash. It seems that the single Hidatsa variety of squash was not suitable for winter storage, so instead they dried slices of summer squash. In both squash and corn, it's clear that the Hidatsa had nary an inkling of pollination - they knew that male squash blossoms didn't form fruits, but had not idea why the plant made them, nor did they know why corn fields next to each other contaminated each other with their variety.
While the agriculture and cuisine in the book aren't particularly useful (I suppose they're interesting from a historical point of view, but less so for a practitioner), the way the Hidatsa use organic implements for every need is incredible impressive. For tools, they used bison scapula hoes, rib hoes, antler rakes, bone knives, spoons made from squash stems(!), and everything else made from cottonwood or ash or willow staves lashed together with rawhide and covered in hides. Food is stored in root cellars lined with a species of grass that doesn't mold over the winter, held in the sides by willow stakes. What's brilliant about this system is that you can always choose branches that are the appropriate shape and size for the job you're doing. Braided grass twine holds dried squash rings together.