Central Virginia Organic Gardener

"And 'tis my faith that every flower enjoys the air it breathes." - William Wordsworth, 1798

Sunday, January 3, 2010


In reading the book I wrote about last week (Williamson, Donna (2008). The Virginia Gardener’s Companion: An Insider’s Guide to Low-Maintenance Gardening in Virginia. Guilford Conn: Globe Pequot) I wrote that I love it when a book stimulates an interest. In this book I found the tantalizing phrase “beautiful Pamunkey soil” which made me wonder where this soil was and if I have it. Pamunkey soil is alluvial, that is, it is left over marine and riverine deposits. We are in a 100-year flood area (most of central VA is) and are not far from the Chickahominy wetlands and the James River. I wondered if I had this type of soil.

So, first I looked up Pamunkey soil and found out a lot about soils in Virginia. For example, from: http://www.va.nrcs.usda.gov/technical/Soils/statesoil.html I read:

“The Natural Resources Conservation Service (NRCS) of the United States Department of Agriculture (USDA) has asked that each state adopt, through legislation, a "State Soil." NRCS asked the Virginia Association of Professional Soil Scientists (VAPSS) to select a soil for Virginia.

In selecting a "State Soil" for Virginia, we were faced with dilemmas that many other states would not be faced with. Virginia covers some 450 miles along its southern boundary, five Physiographic Provinces and nine Major Land Resource Areas. With this kind of diversity in the state, it is hard to select a soil which represents the entire state.

Fortunately, Virginia is blessed with rivers whose watersheds cover each physiographic province. The James River crosses the entire Commonwealth of Virginia and brings sediments from each of the provinces it flows through. These sediments are deposited on flood plains and on deltas along its course, to later form Pamunkey soils on low stream terraces.

This soil, originally mapped as Wickham soil series, was first recognized in Hanover County. Chemical laboratory data revealed that the base saturation (natural fertility) was greater in these soils than is allowed in the Wickham series. The soil was named Pamunkey, the name chosen for a nearby river, which in turn was named for the Pamunkey Indian Nation that lives along the river.

Pamunkey soils are prime agriculture soils in Virginia and occur on about 30,000 acres. Extensive areas of Pamunkey soils have been mapped in the counties of Charles City, Chesterfield, Essex, Goochland, Hanover, Henrico, James City, New Kent, Prince George, Richmond, Westmoreland, and York.

The Pamunkey soils were first used to sustain the Pamunkey Indians, other tribes, and later to grow crops by the settlers at Jamestown. The high natural fertility and high crop yields associated with these soils may be one reason that the Jamestown settlement survived.

Soil Classification: fine-loamy, mixed, semiactive, thermic Ultic Hapludalfs

Pamunkey soils are very deep, well drained soils formed in Piedmont and Coastal Plain fluvial sediments. They are on nearly level to sloping stream terraces. Slopes range from 0 to 15 percent. Mean annual precipitation is about 48 inches, and mean annual temperature is about 59 degrees F. Pamunkey soils typically have a sandy loam surface layer and a sandy clay loam subsoil underlain by sandy and loamy substrata.

Facts about Pamunkey Soil

Pamunkey soil is formed from sediments which originated in every physiographic province in the Commonwealth and therefore represents the WHOLE state better than other soils.

The farm where the representative profile of Pamunkey soil is located, near Jamestown, is the oldest continuously worked farm in the United States. Because of encroaching development, the county of James City has put this historic farm into a conservancy program for the use of agriculture.

The Pamunkey soil, on this oldest working farm in America, produced the world corn yield (308 bushels/acre) and the world record wheat yield (140 bushels/acre) in 2000.

The first settlers at Jamestown grew their crops on Pamunkey soil which may be the very reason they survived.”

Quite a bit of information here, most of which I understand. I do not expect to understand all the many names of soils types (there are a staggering number). This information from the NRCS lead me to believe I was gardening in Pamunkey soil, as it specifically mentioned my county as the place it was first recognized!

So then I went to: http://websoilsurvey.nrcs.usda.gov/app/

This is a way cool web site where you can find the actual soil in your area, provided it has been surveyed (ours was and the report was from 2008). I entered my address, state and got a custom soil report for my area and even got an aerial view of my street, my home with the soils in the area marked. The image above at top is an example of a type of image you can get from this web site, and you can zoom in for closer resolution. From my report I found my the soil in my yard is a combination of Orangeburg-Faceville fine sandy loam or Kempsville-Bourne fine sandy loam (loams are great soil). Both are marine deposits, well-drained and -draining soils. The web site did not specifically call it "Pamunkey soil," but I think this is what I have (alluvial, marine deposits, loamy soils- sounds about right, plus we live in a 100-year floodplain, like almost all this area). Maybe a call to my ag extension agent is in order. I got a lot more details about the soil, the layers of soil and sub-types, the slope of the area, and more information I need to learn more about! This was a really fun exercise and I think it will continue to be fun as I do more exploration. I am lucky to have good soil, though I still need to add compost to maintain soil fertility (even good soils can lose fertility).

Happy gardening!


Anita said...

I'm reminded of a conversation with my brother-in-law who does landscaping. He has totally stripped my neighbor's yard in preparation for new growth (I guess) in the spring. They are selling their home. He was saying how builders sometime take good top soil from one location to another if they need it. He thinks that may have been the case with my neighbor. He was mentioning sand, etc.
You would have been a better person to have that conversation with him. :)

Judy Thomas said...

Yes, it is possible that the soil reported for your lot, according to a soil survey, was disturbed or removed by builders (though I am hopeful this is not the case for us- the house was built in 1987 and the soil survey was in 2008). One particularly difficult thing is when a builder strips the topsoil off a lot or development and back fills it with construction rubble (chunks of concrete, broken bricks, clay, sand). This is very difficult to grow in as it is not very fertile. It is also possible your topsoil was removed and replaced by subsoil, in our case, clay of "fill dirt" (whatever that might be). In addition, heavy machinery compacts soils, squeezing out air pockets and moisture and rendering it less conducive to all the good microscopic critters soil needs to be fertile (fungi, bacteria, yeasts, worms, etc). However, even in this case, the general characteristics of the subsoil (which help determine the characteristics of the topsoil) dominate and the top soil covering your lot can be improved with amendments (like compost).

How It Grows said...

Very informative post - thanks!