Comparing the newly emerging stems of the plains wild indigo (Baptisia bracteata var. leucophaea) in the front prairie with the newly emerging stems of what I thought was Baptisia in the back prairie, I can only conclude that they aren't the same thing. I am quite disappointed.
The photo to the right is of the "pseudo-Baptisia" in the back prairie.
As far as I can tell this early and without fully unfurled foliage (let alone flowers) to help me do a decent identification, the newly emerging plants in the back prairie are probably some type of scurf pea (Pediomelum sp. or Psoralidium sp.). They have palmately compound leaves with 3-5 leaflets. They do not appear to be very hairy nor are they silvery white, which leads me to believe they are probably wild alfalfa or many-flower scurf pea (Psoralidium tenuiflorum).
According to Haddock in Wildflowers and Grasses of Kansas, livestock do not particularly like this plant, and its roots go down to about 10', which makes it fairly drought resistant. Both factors would have helped it survive the heavy grazing this little prairie obviously received in recent years.
The good news is that this plant is also a member of Fabaceae, the Bean Family, and presumably still acts as a nitrogen fixer. I'm looking for any source of fertility I can find for this little prairie! It also looks like it has a rather pretty, purple flower, and I'm a sucker for a pretty plant face.
The last piece of good news is that, if it is indeed wild alfalfa, it should bloom sometime between May and July. Several of the plants look robust enough to manage flowers this year, so hopefully I'll have a true identification sometime soon.
P.S. If anyone recognizes this (or any other plant I've posted up mugshots for), I'd always appreciate help with identifications!