Latest News

June 11, 2018

Dr. Drohan's course on the co-evolution of soil and civilization visited Wexford, Ireland this May for its embedded course component.

April 25, 2018

Dr. Patrick Drohan and Dr. Heather Gall received a grant (the Harbaugh faculty scholar award) from the College of Agriculture at Penn State to collaborate on urban green infrastructure education via their classes. As part of this grant's activities, Dr. Drohan's SOILS 404 (Urban Soils) class visited Greenfield Elementary School this past week to speak to 5th graders about soil and why it matters to people in cities.

February 23, 2018

Lab member Nico Navarro shared his story about soils and why he thinks they are important enough to study for his Master's Degree in Soil Science. We are proud to have him working in our lab at Penn State!

December 6, 2017

Many areas in the world are characterized by shallow soils underlain by weathered bedrock, but root-rock interactions and their implications for regolith weathering are poorly understood. To test the role of tree roots in weathering bedrock, we excavated four pits along a catena in a shale-dominated catchment at the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) in central Pennsylvania.

July 25, 2017

Vegetation removal and soil disturbance from natural resource development, combined with invasive plant propagule pressure, can increase vulnerability to plant invasions. Unconventional oil and gas development produces surface disturbance by way of well pad, road, and pipeline construction, and increased traffic.

May 9, 2017

The advent of real-time, short-term farm management tools is motivated by the need to protect water quality above and beyond the general guidance offered by existing nutrient management plans. Advances in high-performance computing and hydrologic or climate modeling have enabled rapid dissemination of real-time information that can assist landowners and conservation personnel with short-term management planning. This paper reviews short-term decision support tools for agriculture that are under various stages of development and implementation in the United States: (i) Wisconsin’s Runoff Risk Advisory Forecast (RRAF) System, (ii) New York’s Hydrologically Sensitive Area Prediction Tool, (iii) Virginia’s Saturated Area Forecast Model, (iv) Pennsylvania’s Fertilizer Forecaster, (v) Washington’s Application Risk Management (ARM) System, and (vi) Missouri’s Design Storm Notification System. Although these decision support tools differ in their underlying model structure, the resolution at which they are applied, and the hydroclimates to which they are relevant, all provide forecasts (range 24–120 h) of runoff risk or soil moisture saturation derived from National Weather Service Forecast models. Although this review highlights the need for further development of robust and well-supported short-term nutrient management tools, their potential for adoption and ultimate utility requires an understanding of the appropriate context of application, the strategic and operational needs of managers, access to weather forecasts, scales of application (e.g., regional vs. field level), data requirements, and outreach communication structure.

April 19, 2017

By Jeff Mulhollem April 19, 2017 .. .. UNIVERSITY PARK, Pa. — Fragmentation of ecologically important core forests within the northern Appalachians — driven by pipeline and access road construction — is the major threat posed by shale-gas development, according to researchers, who recommend a change in infrastructure-siting policies to head off loss of this critical habitat.

April 3, 2017

Highlights: Pipelines comprised the largest portion of the shale gas industry footprint; Pipelines were the largest contributor to the fragmentation of core forest; Loss of core forest was double on private land compared to public land; Methods to consolidate pipelines with other infrastructure should be used; New pads should be placed near existing pipelines to reduce further fragmentation.

March 22, 2017

This new book chapter highlights the unique characteristics of soils across the United States and discusses their genesis. The chapter is part of a new International Encyclopedia of Geography.

February 23, 2017

Highlights • We developed a Browse Extension to simulate effects of ungulates on the growth and survival of plant species cohorts. • The capabilities of the extension were explored via case studies in the Allegheny National Forest and Isle Royale National Park, USA. • In both model applications, browsing reduced total aboveground live biomass and caused shifts in forest composition. • Simulations that included effects of browsing resulted in successional patterns that were similar to those observed in the study regions. • Neglecting effects of browsing when modeling forest succession may result in flawed predictions of forest biomass and composition in some ecosystems.

January 4, 2017

The identification of unique areas of vegetative potential across the Northern Appalachians is complicated by a long land-use history of vegetation management. We introduce provisional ecological sites and associated state-and-transition models for the region, which can be differentiated by latitudinal drivers of: precipitation and temperature; local parent material and resulting soil differences; and landscape position, slope, or aspect. Identification of ecological sites and associated States or Phases in the Northern Appalachians provides land managers with quantifiable benchmarks for assessing forest compositional shifts due to natural or anthropogenic disturbance. Drohan, Patrick, and Alex Ireland. "Provisional, Forested Ecological Sites in the Northern Appalachians and Their State-and-Transition Models." Rangelands (2016).

November 18, 2016

This new book highlights the anniversary of soil science in the United States. Soils are a critical and often unappreciated resource because they are belowfoot and mostly out of sight. This book brings to you a comprehensive overview of the diversity, beauty, and vital importance of soils to ecosystems, agriculture , forestry, and urban infrastructure. It is intended to be a reference and learning tool that will enhance your knowledge, understanding, and appreciation of the soil resources in the USA. Soil supports all terrestrial life forms, and performs functions critical to the well-being of the global population including nutrient and water storage and supply for plant growth, partitioning of precipitation into ground and surface waters, disposal and renovation of anthropogenic wastes, habitat for soil organisms, and support for roads, buildings, and other infrastructure. Soils are a major reservoir of global carbon and can, with proper management, serve as a sink for atmospheric carbon to reduce greenhouse gasses. Soils are relatively resilient, but are subject to degradation if managed improperly. Only by understanding the properties of and processes occurring in the soil, can the soil resource be conserved and sustained for continued support of the Earth’s population. -L. T. West , M. J. Singer, A. E. Hartemink

July 17, 2016

Dr. Drohan traveled to Ft. Collins, CO this July to participate in a National grazing and grassland workshop for the USDA-ARS and the National Institute of Food and Agricultural. Dr. Drohan was asked to provide an overview of soil health initiatives on forest lands to help set the stage for the workshop and its forthcoming white papers.

June 24, 2016

Dr. Drohan hosted a study abroad program Spring 2016 that culminated with a 10 day abroad program in Southeastern Ireland with Irish agricultural, environment, and cultural organizations.

April 13, 2016

Dr. Drohan and others (alumnus Steve Dadio) were recognized this week by the US EPA by receiving an Honorable Mention for the US EPA Scientific and Technological Achievement Award. This is for their "Research on Understanding the Nature of Urban Soils and Their Role in Stormwater and Sewar management."

March 23, 2016

The recent availability of 1-m laser imaging, detection, and ranging (LiDAR) data in Pennsylvania provides a high resolution digital elevation model (DEM) which could improve on existing USDA-NRCS Order 2 soil survey mapping. The ability of LiDAR derived terrain indices to predict hydric soil presence was evaluated across the Northern Appalachians. We developed a logistic regression model to predict hydric soil presence using a dataset of 1153-field data points and several terrain indices derived from LiDAR DEMs. The best performing regression model included slope derived from a 1-m LiDAR DEM, depressions derived from a 5-m LiDAR DEM, and physiographic region. This model was able to successfully predict 67% of hydric soils and 73% of non-hydric soils from a validation dataset. The model performed better at predicting non-hydric soils compared with hydric soils and was not as effective in low slope areas. This suggests that the 1-m LiDAR hydrologic variables used in the study cannot completely account for soil hydric status.

March 21, 2016

It may be a dim first day of Spring in Happy Valley but we aren't. Left, Shauna Kay Rainford, right Katie Speicher.

January 22, 2016

The PSU SCL is recruiting an MS student to begin July 1, 2016. This student will work with Dr. Drohan, and Drs. Diefenbach and McDill in the ESM department, on a PA Bureau of Forestry study examining how soil chemistry may influence forbe chemistry and deer health. Interested students should contact Dr. Drohan at

November 20, 2015

"Riverine wetlands are perhaps the most important type of wetland to humanity due to dependence on them for supporting aspects of navigation, food, power production, development, flood control and recreation (Smith et al., 2008). Today, their protection is essential for flood control and wildlife habitat, and these goals have resulted in numerous efforts at restoring degraded function."

November 3, 2015

How do a landscape and its people evolve through time? SOILS 499A examines this question and focuses particularly on the role natural resource management has played in the evolution of culture, society, and civilization.