| usda.gov | Phosphorus Index |
| geocities.com | Main Frame |
| csl.gov.uk | Research into New Quarantine Treatments for Horticultural and Timber Products as |
| ca.gov | Smoke Management Program |
| umd.edu | University Of Maryland Agricultural Nutrient Management Program |
| psu.edu | Nutrient and Water Policy Update |
| uni-hohenheim.de | Strategies to Reduce the Emission of Greenhouse Gases and Environmental Toxic Ag |
| montana.edu | The Soil Management Collaborative Research Support Program (SM-CRSP) |
| landinstitute.org | The Land Institute |
| iatp.org | Institute for Agriculture and Trade Policy |
, ,