Soil Samples at Penn State Living Filter (IMAGE) American Society of Agronomy Caption John (Jack) Watson, professor of Soil Physics & Biogeochemistry, is collecting soil samples at Penn State's Living Filter site. Credit Photo credit Zachary Larson. Usage Restrictions Please use with story only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.