question: The the Ur III period , what crop had Sumerians switched to from wheat for their primary crop ?
answer: salt-tolerant barley
turker_answer: In the Ur III period , Sumerians had switched to salt-tolerant barley from wheat for their primary crop .
rule-based: The the Ur III period , had Sumerians switched to salt-tolerant barley from wheat for their primary crop .