the main situation you have to decide on is moisture retention held in the soil. Clover will use less, and certain types can adapt to drought tolerancy very well. Alfalfa cannot, as it needs year round moisture to be a perennial crop. Around here in the dryer climates, I grow 4 different kinds of clover, both in one crop fields, to blends with cover crops and open forage mixes. I would have to say here, especially the white clover is the fav, next to crimson clover and so on.