By his affable manner and down-home speech, you might not figure the man for a college professor and prominent agronomist. But you’d be underestimating Dr. William Johnson, Jr. By the time Johnson was 15, he’d become a member of Future Farmers of America. He earned his bachelor’s and master’s degrees in agronomy at Arkansas State University-Jonesboro. At first he was taking 16 hours a semester while also working 40 hours a week at a steakhouse to pay his way through college. In 1995 received his PhD from the University of Arkansas. On his own farm, the legacy property of his ancestors, Johnson is growing 300 tomato plants of multiple varieties this year, along with a couple dozen jalapeño pepper plants, and a limited crop of okra.And then, of course there are the pecans…