Researcher guides design of Smithsonian exhibit on soil, life on Earth

July 21, 2008

University Park, Pa. -- A Penn State soil scientist helped to lead the design of a new temporary exhibition that opened this weekend at the Smithsonian's National Museum of Natural History in Washington, D.C. "Dig It! The Secrets of Soil" exhibition reveals the complex world of soil and how this hidden ecosystem supports nearly every form of life on Earth.

"Seven years ago, a visit to the Natural History Museum inspired myself and another soil scientist, the late Tom Levermann, to approach the Smithsonian about an exhibit devoted entirely to soils," said Patrick Drohan, assistant professor of pedology in the Department of Crop and Soil Sciences, Penn State's College of Agricultural Sciences. "The enthusiasm of the entire soil community and the Smithsonian researchers and curators, along with major financial support from several organizations, turned the idea into reality very quickly, compared to most projects. My adviser, Gary Petersen (distinguished professor emertius), helped me attain the first grant to get the ball rolling."

"Dig It!" shows how every type of soil is unique. Visitors can observe the way water moves through different soils in tumbler tubes containing sand, silt, clay and loam. The flow of water through soil can affect minerals and gases and all life that depends on soil. Soil color tells fascinating stories about mineral compositions and soil formation or history. "Dig It!" color cards help visitors to unveil the stories behind soil samples. Visitors also can get in touch with their inner detective and learn about the soil food web in the "Matters of Life and Death Theater."

The exhibition opened Saturday, July 19, and will run through Jan. 3, 2010 at the Smithsonian's National Museum of Natural History, and is sponsored by the Soil Science Society of America and the Nutrients for Life Foundation, which is underwritten by The Fertilizer Institute. Photos of the exhibit are at:

"Dig It!" includes interactive displays, hands-on models, videos and soil samples. Curious visitors will get the dirt on this little-known subject through audiovisual and interactive components, from a set of interactive soil stratigraphy blocks to a crime scene investigation video focusing on the processes of decay to a computer kiosk where visitors can learn about their state soil.

Visitors also can explore soil found in their own backyard and in obscure locations, with 54 soil samples representing each U.S. state and territory and the District of Columbia, as well as soil maps and touchable soil models from around the world. In doing so, visitors will discover a world teeming with life. In fact, so many organisms contribute to the health of soil that scientists have not even named them all. After examining soil close up, exhibition visitors can step back and see the "big picture" with a world map and interactive stations that present the connection between soil and global systems.

Models demonstrate the roles of soil around the house and the formation of soil in commercial and residential construction, dams, playing fields, neighborhoods, roads and in food production. An evocative video explains soil's role as a "secret ingredient" in such household goods as medicines, food, wine, textiles, paint, cosmetics and pottery.

"This is the most ambitious exhibition ever dedicated to soils, a resource as important to life on Earth as water and air," said Patrick Megonigal, lead curator and soil scientist for the Smithsonian Environmental Research Center, which is located in Maryland near the Chesapeake Bay.

The National Museum of Natural History, located at 10th Street and Constitution Avenue N.W. in Washington, D.C., is open from 10 a.m. to 7:30 p.m. daily through Aug. 31 and from 10 a.m. to 5:30 p.m. thereafter. Admission is free. More information about the museum is available at or by calling Smithsonian Information at (202) 633-1000, TTY (202) 633-5285.

Protecting soils is important to our survival

The Penn State Soil Characterization Lab, directed by Drohan, conducts research in changes in soil physical, chemical and mineralogical properties due to disturbance and how ecosystems change in response; soil genesis, classification, and mapping; problematic soil physical and chemical properties in urban environments and their management; and land use assessment based on soils.

The past year has been a busy one with outreach and educational activities as well, including training workshops for high school science teachers about including soil topics in their curriculum, most recently at the Pennsylvania Envirothon. At the end of July, Penn State will host U.S. and international scientists for the first hydropedology research conference: "Water and Soil: Key to Sustaining the Earth's Critical Zone."

Another soils research project at Penn State is the Shale Hills Critical Zone Project, an NSF-funded, five-year project to study the rate and mechanisms by which soil is formed from bedrock and the impact of weather and water on that process. Besides the Shale Hills site near Stone Valley, there are satellite sites in areas including the mid-Atlantic region, New York, Virginia, eastern Tennessee, northern Alabama and Puerto Rico. Penn State is partnering with English universities on similar weathering science projects, with support from the Worldwide Universities Network. The full story is at:

In his own published work, Drohan has made a proposal on recognizing natural soils that are rare or threatened. "Just as we lose animal and plant species to extinction, we also are seeing soils damaged or destroyed due to pressures from multiple human-caused destruction which can put life at risk," Drohan said. "Worldwide, the effects of global warming are predicted to lead to the disappearance of permafrost within 1,000 years, which would result in the extinction of a whole order of soils -- gelisols, in the U.S. system of soil taxonomy, which cover approximately 8.6 percent of earth's ice-free land area.

"Many examples throughout history also exist of civilizations rising and falling in part due to their management of soil. "The best soils for food production are often ideal for building sites, and their favorable characteristics attract intensive development, often resulting in their degradation and significant economic loss," he added.

Top 10

To capture the public imagination, Drohan has even created a Top 10 list of the importance of soil:

10. Unless you live in a houseboat, your house is likely built on soil (even a houseboat is built from wood that came from a tree growing on soil).

9. Like milkshakes? Most have clay in them.

8. Like global warming? Then be happy that soil sequesters about two times the amount of carbon found in all vegetation and the atmosphere combined.

7. Care for a beer? Not going happen without those plants that just happen to grow in soil.

6. Cotton doesn't just come from the mall. You get a lot of your clothes from crops that grow on soil.

5. Ever been sick? You probably have taken an antibiotic that was derived from organisms in the soil.

4. Ever drink water from a well or stream? You could likely die of contaminated water if there was not soil to filter water for drinking.

3. Enjoy eating? You would likely starve to death if you could not eat plants that grow in soil.

2. Like breathing? You probably would not be breathing if there was not soil for plants to grow in that produce the oxygen keeping you alive.

1. Imagine a world where nothing that died decomposed -- bet you really like soil now.

The Penn State Soil Characterization Lab is at:

The Smithsonian Exhibition information is at:



  • Patrick Drohan, Penn State soil scientist. Click on the image for more photos.

    IMAGE: Greg Grieco
Last Updated November 18, 2010