Is it possible to grow soybeans in the high desert of southern California?
I think so. I understand from one of the personnel at the Farmington research station in New Mexico (elevation 5600 feet) that soybeans have been grown successfully there. I presume irrigation would be needed, and I would worry a little about temperatures. Soybeans would have trouble tolerating many days above 100 degrees, and could have trouble tolerating a lot of wide swings in temperatures between daytime highs and nighttime lows (eg. 40 degrees or more).