Reuters: The Obama administration should drop its proposal to end the direct payment subsidy to large U.S. farmers, the National Farmers Union said on Monday, pointing to a slump in dairy and crop prices. The White House proposal has few supporters among farming groups and farm-state legislators. It calls for a three-year phase-out of direct payments to grain, cotton and soybean growers who have more than $500,000 a year in sales. Delegates at the NFU convention in suburban Washington …