North Carolina Soil Geomorphology Tour

At the beginning of this week I helped some faculty in the NCSU Dept. of Soil Science with the North Carolina Geomorphology Tour. The tour is a one-week field class that starts at the outer banks of North Carolina and ends in the mountains at the Tennessee boarder. Along the way the students examine and classify soils of all different types while the professors provide some interpretation and lead discussion on what conditions caused each soil to form.

At each of the sites where we stopped, all of the students broke out into six groups and worked to describe and classify the soil at their assigned location. My job was to bounce around from group to group to answer any questions and help walk them through the Keys to Soil Taxonomy as they classified their soil. I also helped a little with the discussion at each stop.

Here are some pictures I took along the way…

The Wright Brothers Memorial

Our first stop on the trip was to the Wright Brothers Memorial at Kitty Hawk, NC. This memorial commemorates the first ever self powered flight. It’s also located on a huge dune that overlooks all of the development in the area. There were several soil science concepts we covered here, including the form of the large wind-blown dunes on the outer banks, desication of plants (trees especially) due to the wind and salt and how that affects what plants can grow in this environment, the availability of drinking water on the outer banks, and how growth was limited on Kitty Hawk and Nags Head by the city not developing a public sewage system (the property owners can only build a house as big as their septic system can handle… thus no 8 story condos).

The Wright Brothers Memorial Dune

We then moved on to the beach. The North Carolina Outer Banks are a system of islands that move seaward or landward depending on sea level (on a geologic time scale). Currently the islands are moving landward with ocean level rising since the last ice age. However, that doesn’t stop people from developing the outer banks with multi-million dollar homes that are rented to tourists. These houses are annually at risk of being washed into the ocean.

A house that almost fell into the drink is now protected by “beach renourishment”. Would you buy a house here?

However, through successful lobbying, the State of North Carolina and the federal government have stepped in to pay for “beach renourishment, which is the act of dredging sand from 2 or 3 miles off the coast, and blowing it back on to the beach. This in turn protects the houses for as long as the sand  lasts. It is constantly being eroded, so it will take another huge influx of taxpayer money in a few years to protect these million dollar homes.

The Soil Geomorphology class looks on as the “beach renourishment” sand erodes back into the ocean.

As a soil scientist, I think that it is unwise for the government to pay to protect million dollar houses, or any houses for that matter, on land that will inevitably be eroded away by beach erosion some day, nor should it fund the construction of cities in annually flooded areas. I think it’s more logical to let nature run its course most of the time and not build permanent structures on non-permanent landscapes.

The “beach renourishment” added about 200 meter wide strip of sand to this beach. Beforehand the beach was literally underneath the stilts of the houses.

That was it for the first day. Most of the first day had been taken up by the 4 hour trip from Raleigh to the outer banks.

On the second day we first stopped at Nags Head Woods to look at soils in a Maritime Forest. We then went to Manteo to look at a variety of Spodosols (an order of soils that develop in sandy areas under pine forests, pictured below).

Spodosols at Manteo, NC

After that we went on to the mainland where we stopped at Somerset Place on the shore of Phelps Lake, which was once one of the biggest plantations in the state of North Carolina with an area of 100,000 acres. Somerset place had over 800 slaves, cumulatively, and a peak area under production of around 8,000 acres. They grew rice, corn, wheat, and more. They also planted some amazing bald cypress trees as you can see with my picture below. By the way, bald cypress are the species I research for my graduate work.

Colby standing next to a bald cypress tree (Taxodium distichum) at Somerset Place.

We did one more stop on the shore of Phelps Lake. Phelps Lake is a pocosin lake. Pocosins are swamps that form on lands that are very wide (on the order of many miles), and very flat (as in flat as a pancake) where the source of water is rainfall, and the water cannot drain fast enough so it only leaves via transpiration. Over time these wet conditions allow for the accumulation of plant matter to create Histosols. The swamp that forms is actually the highest point on the landscape, thus bringing us to the term “pocosin” which is Algonquin Indian for “swamp on a hill”. When lakes form on these pocosins, they are termed pocosin lakes. These are the only naturally occurring lakes in the state of North Carolina.

Dr. Lindbo explaining how pocosins and pocosin lakes form.
Cypress trees growing on the organic soil shore of Lake Phelps

We dug some profiles in the Histosols around the edge of the lake so that everyone there could see and feel organic sols.

Histosols near the edge of Lake Phelps

Our last stop was to look at some lower coastal plain Ultisols at the Vernon James Tidewater Research Center (an extension and research farm for NCSU).

Vernon James Center Ultisols

After that Alan Meijer, a PhD student and extension agent for the NCSU Dept. of Soil Science gave us a tour of the different tillage, planting, and harvesting equipment used on the research farm.

Alan Meijer presenting tillage equipment

We ended the long day with pizza and a presentation from Paul Lily, Soil Science Professor Emeritus, on the history of North Carolina with a soils and agriculture perspective.

On the third day (and last day for me, I had to get back to Raleigh to do real work) we made our way up the coastal plain and back to Raleigh. The coastal plain is an area along the Atlantic coast of the US that consists of marine, and alluvial sediments (sediments deposited by the ocean and by rivers). The oldest parts of it are at about 300 feet elevation, the youngest parts are at the beach. We stopped to look at some scarps (abandoned beaches from times of higher ocean levels), some flood plains, and some toposequences (we examined soils along a hillslope to see how topography affected the soils).

Some Tupelo Gum trees in the backswamp of the Tar River floodplain
Soil profiles along a toposequence in the Coastal Plain.
A gully that was down-cut since settlement of North America has exposed a nice soil profile of a Grossarenic Hapludult.

That’s pretty much it for the leg of the trip in which I participated. I did do the full trip as a student the last time the course was offered (in 2010). If you would like to read about that adventure you can read about it on my personal blog here. All of the pictures from this trip are available on my Soil Geomorphology Tour 2012 Picasa Album. Pictures from the entire week’s trip from 2010 are available on my Soil Geomorphology Tour 2010 Picasa Album.

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