Fourth-generation Olathe farmer Randy Friend stopped his pickup truck next to a row of corn whose green leaves were limp and curling, with a gray tinge. Friend’s corn was stressed as the valley endured a July heat wave with temperatures nudging close to 100 degrees. “I hate to see it looking like that with our water situation,” Friend said. Next was a field of onions, a thirsty crop with a long growing season. The furrows between the dark-green…