Sjoerd W. Duiker is an Extension Specialist and Professor of Soil Management and Applied Soil Physics at Penn State University. Dr. Duiker received his M.S. in Tropical Crop Science from the Agricultural University in Wageningen, the Netherlands, and his PhD in Soil Science from Ohio State University. He joined Penn State in 2000. His current research interests include the soil health and productivity effects of soil compaction, soil tillage and no-tillage, grazing, and cover crops. Dr. Duiker has published 36 peer-reviewed papers and more than 100 extension publications. He is a member of the American Society of Agronomy, the Soil Science Society of America, and the Soil and Water Conservation Society.