John Deere has decided to end its business with dealer R.N. Johnson in Walpole, N.H., after 84 years. The retailer says it will continue to service the equipment it has sold, maintain the John Deere museum and sell another brand of equipment. "We are going to stay in business," said Alan Johnson, the third-generation owner of the business. "We are going to continue to service the many people who bought John Deere products over the years."