The chorus of clean-energy advocates is growing louder – and more politically powerful – now that farmers are singing along. And they have good reason: Energy crops. Raw materials such as corn, soy, wheat, trees and even animal manure can be processed into cleaner-burning next-gen fuels. According to a new article in Grist.org, leaders of 70 agriculture groups recently joined the ambitious 25 x '25 alliance. It advocates that 25 percent of U.S. energy supplies come from America’s working lands – either from their crops or windmills and solar panels installed on those lands - by 2025.