Mike Wallace sat in his pickup truck on a dusty back road near his farm outside Leachville, Arkansas, typing impatiently into his cell phone. “I’m waiting on you,” he wrote. “You coming?” It was hot for late October. The rows of soybeans, cotton, and corn, which just days ago had spread across much of the region, were largely gone, replaced by dry, flat dirt. The 2016 harvesting season was nearly over. A minute passed, and Wallace typed another message, sounding slightly triumphant. “Looks like