I mentioned impression earlier. There's a way to rough up the ground that may work for you. I use pigs.
Sepp Holzer recommends them for clearing ground and roughing it up prior to planting trees. (page 108-111, "
Desert or Paradise", Sepp Holzer)
Water, dust and seeds(you can cast the seeds or nature will provide some eventually) will collect in the depressions the pigs (or whatever) have made. The seed will sprout. The grasses and other plants will collect rainwater and dew. The depressions are more sheltered from wind and sun as well.
Do you have access to electricity? You'd want an electric fence if you go this route.