This week, a bunch of Wall Streeters have traded in their suits and ties for jeans as they make the annual pilgrimage to the Midwest to check out this year's crops. It's what New York-based Societe Generale commodities analyst Chris Narayanan describes as "boots on the ground analysis." "It's a way for people covering the space in whatever capacity to get an idea as to what's out there and talk to people," he told us in a telephone interview.