USDA. NAL. Water and Agriculture Information Center.
Soil Amendments and Nutrient Management
National Center for Appropriate Technology. ATTRA - National Sustainable Agriculture Information Service.
Publications and other resources on how to assess, improve and maintain soil health for both croplands and pastures.
Environmental Protection Agency.
Encourages the use of methane recovery/biogas technologies at confined animal feeding operations that manage manure as liquids or slurries. This site includes basic technology overview, program accomplishments, experts, publications and technical tools, workshops and conferences and a guide to currently operating systems.