It’s the sort of edge any trader would covet -- and one the authorities were actually hoping to prevent. Yet the U.S. Department of Agriculture may well be clearing the way for some Wall Street speed demons to trade on market-moving data before others. Abandoning decades of precedent, the agency has decided to only post its reports directly on the web, rather than also release them via accredited media. While that may seem like a democratic move, it actually could set the stage for a winner-takes-all arms race to grab the info first. The development, announced Tuesday, is the latest saga for crop markets that have increasingly seen high-speed algorithms taking over and running circles around slower human counterparts, a theme popularized by Michael Lewis’s "Flash Boys." Fiber-optic cables, short wave radio, microwave towers: all have been employed to trade faster.