Charles L. Walthall PhD National Program Leader Soil and Air Resources Management Program USDA ARS NPS 5601 Sunnyside Avenue Room 4-2278 Beltsville, MD 20705-5140 Email: charlie.walthall@ars.usda.gov 301-504-4634 301-504-6231 (Fax) 443-968-0660 (Cell)
Charles L. Walthall PhD National Program Leader Soil and Air Resources Management Program USDA ARS NPS 5601 Sunnyside Avenue Room 4-2278 Beltsville, MD 20705-5140 Email: charlie.walthall@ars.usda.gov 301-504-4634 301-504-6231 (Fax) 443-968-0660 (Cell)