On an ordinary weekday, Dr. Ian Merwin is a Cornell University teacher and researcher who has put his mark on the orchards of New York—and elsewhere—because of his work with orchard floor management systems, including nutrient dynamics, soilborne diseases, ground cover, and weed control. But in the evenings and on weekends, Merwin puts on the work clothes of an apple grower and tends an unusual orchard on his 64-acre Black Diamond Farm near ­Trumansburg, New York. There, he grows the apples and other fruits that he and his wife, Jackie, consider to be ­distinctive and top quality—some of them old […]