Patrick Drohan, Ph.D.

Patrick Drohan, Ph.D.

  • Professor of Pedology & Graduate Program Chair
452 Agricultural Sciences and Industries Building
University Park, PA 16802

Areas of Expertise

  • Soil Science
  • Watershed Management
  • Landscape Ecology
  • Natural Resource Management


  • Ph.D., Soil Science, The Pennsylvania State University, 2000
  • M.S., Environmental Pollution Control. The Pennsylvania State University, 1996
  • B.S., Natural Resource Management, Cook College-Rutgers University, 1992


  • 2001 — University of Maine, Maine Compost School, medium- and large-scale composting certification.

Responsibilities and Interests

Dr. Patrick Drohan's research examines people's use of landscapes and the accompanying changes in soil function across the larger ecosystem the soil supports. His research addresses basic science questions, but also demonstrates how this new knowledge can be used in applied research to improve land management and ecosystem stability. Dr. Drohan has taught over 24 different courses in the natural and physical sciences, and currently teaches: urban soils; soil genesis and classification; field interpretation of soil properties; and study abroad courses in Scotland and Ireland on soil and society's co-evolution through time. His current research addresses changes in dynamic and inherent soil properties across time scales spanning the Pleistocene to present. He is an Associate Editor for: the Soil Science Society of America Journal, Agricultural and Environment Letters, and Soil Use and Management. He is a member of the Soil Science Society of America's (SSSA) Council of Soil Science Examiners and past SSSA Pedology Division chair. He is a co-founder of the Smithsonian Soil Exhibit Project, Dig It, and in recognition of his work in support of Dig It, he received a President's Citation for Outstanding Service from the Soil Science Society of America. See my personal page for more detailed information.


  • 50% Teaching
  • 50% Research

Courses Taught

  • SOILS 403 - Soil Morphology Practicum
  • SOILS 404 - Urban Soils
  • SOILS 416 - Soil Genesis and Classification
  • SOILS 497A - Soil and Its Management Through Time in Scotland
  • SOILS 597 - Soil health for one health
  • SOILS 499a and 499b - Co-evolution of land and people, and "Maymestor" in Wexford Ireland
  • SOILS 497D - Paleosols
  • SOILS 516 - Field Soil Genesis


Professional Background

  • Associate Professor, Department of Ecosys. Sci. and Mgmt., The Pennsylvania State University, University Park, PA. 2013–present.
  • Assistant Professor, Department of Ecosys. Sci. and Mgmt., The Pennsylvania State University, University Park, PA. 2012–2013.
  • Assistant Professor, Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA. 2007–2012.
  • Director, Pine Lake Institute for Environmental & Sustainability Studies, Hartwick College, Oneonta, NY. 2006–2007.
  • Assistant Professor, Department of Geoscience, University of Nevada, Las Vegas, NV. 2004–2006.
  • Assistant Professor, Department of Environmental Studies, University of Nevada, Las Vegas, NV. 2003–2004.
  • Assistant Professor, Shepherd College, Institute for Environmental Studies, Shepherdstown, WV. 2000–2003.
  • Ph.D. Graduate Teaching Assistant, Dept. of Agronomy (now Crop and Soil Sciences), The Pennsylvania State University. 1996–2000.
  • M.S. Graduate Research Assistant, Environmental Pollution Control Program, The Pennsylvania State University. 1994–1996.

Selected Publications

Urban Soils

  1. Shuster, W. D., Dadio, S., Drohan, P., Losco, R., and J. Shaffer. 2014. Residential demolition and its impact on vacant lot hydrology: Implications for the management of stormwater and sewer system overflows. Landscape and Urban Planning, 125:48-56.
  2. Shuster, W., Barkasi, A., Dadio, S., Drohan, P.J., Gerber, T., Houser, T., Losco, R., Reinhold, K., Wander, J., and M. Wigington. 2011. Moving beyond the udorthent — a proposed protocol for surveying urban soils to service contemporary urban ecosystem management data needs. In Press, Soil Survey Horizons.
  3. Mrozek, S.A., B.J. Buck, P.J. Drohan, and A.L. Brock. 2006. Decorative landscaping rock as a source for heavy metal contamination. Soil and Sediment Contamination 15(5):471–480.


  1. Fink, C. and P.J. Drohan. 2016. High resolution hydric soil mapping using LiDAR digital terrain modeling. Soil Science Society of America Journal.
  2. Erich, E. and P.J. Drohan. 2012. Genesis of freshwater subaqueous soils following flooding of a subaerial landscape. Geoderma 179-180:53-62.
  3. Erich, E., Drohan, P.J., Ellis, R.L., Collins, M.E., Payne, M., Surabian, D. 2010. Subaqueous soils: their identification and importance in ecosystem management. Soil Use and Management. 26:245–252.
  4. Elliott, P.E. and P.J. Drohan. 2009. Clay accumulation and argillic-horizon development as influenced by aeolian deposition vs. local parent material on quartzite and limestone-derived alluvial fans. Geoderma. 151:98–108.
  5. Yonovitz, M. and P.J. Drohan. 2009. Pore morphology characteristics of vesicular horizons in undisturbed and disturbed arid soils; implications for arid land management. Soil Use and Management. 25:293–302.
  6. Drohan, P.J., G.W. Petersen, and E.J. Ciolkosz. 2003. Soil survey mapping unit accuracy in forested field plots in northern Pennsylvania. Soil Science Society of America Journal 67:208–214.

Land Use/Ecosystem Change

  1. Fink, C. and P.J. Drohan. 2015. Dynamic soil property change in response to natural gas development in the northern Appalachians, U.S.A. Soil Science Society of America Journal, 146-154.
  2. Ireland, A. and P.J. Drohan. 2015. An approach for preliminary delineation of ecological sites in forested, Northern Appalachian landscapes. Soil Science Society of America Journal, 79:185-192.
  3. Drohan, P.J. and M. Brittingham. 2012. Topographic and soil-specific challenges facing Marcellus Shale gas development in Pennsylvania and the northcentral Appalachians.  Soil Science Society of America Journal, 76:1696-1706
  4. Drohan, P. J., M. Brittingham, J. Bishop, and K. Yoder. 2012. Early trends in landcover change and forest fragmentation due to shale-gas development in Pennsylvania: a potential outcome for the northcentral Appalachians. Environmental Management, 49:1061-1075.
  5. Stolt, M.J. Drohan, P.J., and M.J. Richardson. 2010. Dynamic soil properties: Insights and approaches for mapping soil organic carbon. Soil Science Society of America Journal. 74:1685–1689.
  6. Boxell, J., Drohan, P.J. 2009. Surface soil physical and hydrological characteristics in Bromus tectorum L. (cheatgrass) versus Artemisia tridentata Nutt. (big sagebrush) habitat. Geoderma. 149:305-311.
  7. Drohan, P.J. and D.J. Merkler. 2009. How do we find a true gypsophile? Geoderma. 150:96-105.
  8. Drohan, P. J., C.N. Ross, J. Anderson, R. Fortney, and J. Rentch. 2006. Soil and hydrological drivers of Typha latifolia encroachment in a marl wetland. Wetlands Ecology and Management 14(2):107–122.
  9. Drohan, P.J., G.W. Petersen, and S.L. Stout. 2002. A study of sugar maple (Acer saccharum Marsh) decline during 1979 to 1989 in northern Pennsylvania. Forest Ecology and Management 170(1–3), 1–17.

Soil Outreach/Education

  1. Drohan, P.J. 2017. Future challenges for soil science research, education, and Soil Survey in the USA. In: West, M; Singer, M.J.; and A.E. Hartemink (eds). The Soils of the USA. Springer International Publishing, New York. (pp. 373-384).
  2. Lin, H., Drohan, P.J., and T. R. Green. 2015. Hydropedology: The last decade and the next decade. 79:357-361.
  3. Hartemink, A. E., Balks, M. R., Chen, Z. S., Drohan, P., Field, D. J., Krasilnikov, P., and Walter, C. 2014. The joy of teaching soil science. Geoderma, 217:1-9. 
  4. Drohan, P.J. Havlin, J.; Megonigal and H.H. Cheng. 2010. The “Dig It!" Smithsonian Soils Exhibition: Lessons Learned and Goals for the Future. Soil Science Society of America Journal. 74:697-705.
  5. Megonigal, J.P., Stauffer, B., Starrs, S., Pekarik, A., Drohan, P.J. and J. Havlin. 2010. “Dig It!": How an Exhibit Breathed Life into Soils Education. Soil Science Society of America Journal. 74:706-716.
  6. Drohan, P.J., and T. J. Farnham. 2006. A proposal for the formal designation of rare and threatened soils. Soil Science Society of America Journal 70: 2086–2096.