These very shallow soils have a surface layer of pinkish-gray, calcareous, moderately alkaline stony loam that is about 5 inches thick over limestone. All of this association is used as rangeland or for wildlife or recreation. Hueco Tanks Park, a recreational and historic site, is on the association.
I can't find the soil genetic line right now (a.k.a. it's proper name starting at the order level)
My first thoughts: There is no soil to garden here. Anyone trying to improve the soil for gardening is in it for the long-term ;-) So to grow any non-native plants, you'd essentially be container gardening. Bring in yer soil; maintain moisture content with compost/organic matter; strategic water supply; protect with shade; use that humanure you bragged about.
What will your humanure do to this soil if incorporated long-term? Will its acidity help breakdown that limestone rock? Hmmm....
Any other suggestions, other than head on over to the grocery store?