BOISE, Idaho — Matt Wissel grows vegetables and melons on about 80 acres in Nampa, just as his father and grandfather did. He runs his family’s farm, Wissel Farms, with his wife, Benita. He’s watched as acre after acre of farmland has given way to houses. If residential developments and big-box stores keep taking over farmland in Canyon County, Wissel says, there won’t be much agriculture ...