In welcome news for environmentalists, the U.S. Senate approved a farm bill yesterday that would double spending for conservation programs to $22 billion over the next decade. If it becomes law, the farm bill — which also includes provisions to clean up urban drinking water, protect forests from urban sprawl, and conserve wildlife habitat — would be the most sweeping environmental legislation since the Clean Air Act of 1990. The five-year, $44.9 billion bill also strictly limits subsidies to individual farmers and doubles the administration’s request for food stamps, which would make the Agriculture Department’s nutrition program the second-largest anti-poverty effort in the nation. The bill is far more eco-friendly and socially oriented than the version passed by the House last fall; lucky lawmakers are now faced with the task of reconciling the two versions.