What the closing of Kansas City’s Mercantile Exchange can teach us about how Wall Street stopped treating food like food.11 FEBRUARY, by Elizabeth RushJust off of Country Road 518 in Hopewell, New Jersey, sits Double Brook Farm. It’s run by a self-exiled New Yorker but it’s not one of those now-standard upstart farms, with roving bands of earnest college kids tending rocket and a hearty couple of ex-Brooklynites overseeing the whole grass-fed operation. Double Brook’s turn-of-the-century-barn, its grazing cattle, and its hundreds of Rhode Island Reds clucking and strutting about all belong to Jon McConaughy, a 46-year-old with an all-American face, a football player’s build, money to blow, and a beautiful wife. Last year, McConaughy exchanged a two-decade long career as a commodities trader on Wall Street for these two hundred acres.Double Brook, a small farm specializing in grass-fed meat, free range poultry, and various vegetables symbolizes one of the most unexpected turns the American economy has taken in recent years. For decades, banks have shied away from granting loans to farmers because, like restaurants, farms are considered risky investments. But the tides might be turning as the price of nearly every commodity on the face of the earth is on the rise.