A technique for dramatically increasing the fertility of soil that was developed by the indigenous peoples of the Upper Amazon Basin and the Itza Mayas of southern Mexico enables members of the cabbage family to thrive in frigid wintertime conditions. Plants in the cabbage family were probably not grown by Native American farmers until after the arrival of Europeans. Substantial evidence of biochar agriculture in the terraces at Track Rock Gap, Georgia was one of the strongest links to the former presence of Itza Maya farmers and possibly, also South Americans.
The opening scenes of the premier of the History Channel’s “America Unearthed” provided viewers glimpses of an agricultural experiment that is mimicking the growing conditions of the Track Rock Gap terraces. Both the Track Rock Terraces and the experimental garden face the southwest, which exposes them to the hottest growing conditions in the afternoon. Normally, this orientation is undesirable in the Sunbelt. The location’s suitability for agricultural is worsened by the shade of a 4,700 feet (1432 m) mountain immediately to the east blocks the morning sun.
Those readers who did not get to watch “The Mayas in Georgia” on December 21,2012 may view it online at the following URL: http://www.youtube.com/watch?v=ywLNdUnZr4s
The strange sounds in the background of the TV program’s beginning were made by a super-sized, black, stub-tailed gecko that supposedly, only lives in the Maya Highlands of Central America. In fact, the very first scene was created with a close-up lens and a microphone inside the garden. This "illegal alien" gecko family was already living in the adjacent cabin’s basement when construction of terraces began. No one has yet explained why this relic from the Cretaceous Period is thriving in the Gold Fields near Dahlonega, GA. The winter temperatures are theoretically too cold for this species of lizard.
Theoretically, the geology and soil chemistry of both agricultural sites are highly undesirable for most agricultural pursuits. The rock strata near the surface are soapstone, quartz or greenstone. The highly acidic soil contains unusually high levels of gold, copper, zinc, phosphorous and iron, but very little calcium, potassium or manganese. A collapsed tunnel of a 19th century gold mine is about 200 yards from the experimental garden. Yellowish-red clay underlies about 12 -18 inches (30-50 cm) of loam created by centuries of decayed leaves. The loam is high in nitrogen, but almost devoid of many minerals needed by vegetables and fruits. The soil is ideal for vinifera and wild grapes, however. Both Track Rock and the woods around the experimental garden are choked by massive wild grape vines.
Biochar agriculture is a term first created by a team of archaeologists and botanists, who were studying a previously unknown civilization in the Upper Amazon Basin. The term was originally popularized in the best-selling book, “America 1491” by Charles Mann and a special on the History Channel. Scientists discovered that unique bacteria thrived in the man-made soils in which charcoal, pottery shards and human refuse was mixed. The bacteria convert sterile soil into extremely productive soil, which literally grows. Native American farmers also made extensive use of urine as a natural fertilizer. Human urine contains high levels of nitrates, potassium and calcium. Unlike fecal matter, it usually does not contain pathogenic bacteria.
During the last weekend in April, the site of the experimental garden was hacked out of steeply sloping woodlands that had never been farmed, but probably were pastured in the 1800s. The sawn down trees were used to construct a series of terraces that were filled with top soil. This is a probable scenario for the terrace complexes now being discovered at several locations in the Southeast. It is likely that construction of stone-walled terraces followed construction of timber walled terraces by at least a century or more.
A simple rain runoff catchment system was constructed with timbers and ditches to channel water from uphill into the experimental garden. The water was stored in ditches within every fourth terrace, so that it could trickle down into the remaining terraces.
Organic kitchen waste, eggshells and bones were continually thrown onto the terraces throughout the growing season. Urine was mixed at a 4:1 ratio and applied to all plants except the bean family. I also cheated and applied natural lime to the rows of corn and beans. The soil was far too acidic to grow these plants otherwise. I did not use any other chemicals or insecticides.
Because of state mandated burning ban enacted on May 1, 2012 the only source of charcoal during the summer was from outdoor cooking fires. The oven in the cabin does not work, so I intentionally cooked as many meals as possible on the terraces with wood fires. The state ban exempted fires for outdoor cooking. Meals were cooked on grills, griddles, cast iron pots and a massive 10 gallon cast iron Dutch oven over hot coals. Even in mid-winter temperatures, native legumes are still thriving at locations where cooking occurred.
A wide variety of plants indigenous to the Americas were planted in the experimental garden. These included several types of white potatoes, beans, peas, tomatoes, peppers, squashes, pumpkins and maize. Also successfully grown were watermelons and cantaloupes that originated in Africa and egg plants, which originated in India.
During June of 2012 the Southern Highlands experienced the highest temperatures ever recorded. Most of conventional gardens turned brown. The experimental terrace garden stayed green throughout the summer. Indigenous members of the bean and pea family stayed productive until late October.
The only problem in the first year experiment was the presence of large fungi populations in the woodland soil. Native American farmers burned over planned garden sites after clearing forests. The heat from the fires and natural lye from the ashes killed most fungi spores near the surface. However, the outdoor burning ban made this impossible. As a result, the early crops of butternut and coushaw squash were destroyed by fungal infections. When the temperatures cooled, later crops of these squashes that are native to the Southeastern United States were abundant.
As soon as the outdoor burning ban ended on October 1, I began burning a series of massive bonfires created by piles of dead trees and limbs around the long abandoned cabin. The coals were immediately spread on the experimental garden and worked into the soil. The equivalent of pottery shards was created by adding red clay that had been vitrified by the intense heat.
I then planted small seedlings of cool weather plants that are native to Europe. These included onions, kale, snow peas, Brussels sprouts, two varieties of collards and three varieties of cabbage. The big advantage of fall gardening is that cool temperatures kill off all the predatory insects and noxious weeds.
Initially, the fall garden seemed headed toward failure. The tall hardwoods that mimicked the shading effect of the mountain behind Track Rock Gap completely shut out the sun. The seedlings received very little direct sun and barely grew at all. After the leaves fell off the trees in early November, they did begin growing, but I assumed that mid-November hard frosts would soon kill the plants.
Temperatures in the twenties and low thirties (Fahrenheit) did not kill the plants. Apparently, the rich soil heavily mixed with charcoal and the mulching of fallen leaves protected the plants from frost damage. They started growing and continued to grow throughout December and January. I began eating homegrown collards and Brussels sprouts in December and by mid-January the broccoli was ready for consumption. Another factor that apparently protects the plants is the constant dampness of the soil due to terrace structure.
The terrace garden experiment strongly suggests that biochar agriculture could have a major impact on the profitability of Sunbelt farming operations. Locations in full sun could produce second crops of cool weather vegetables without the need for expensive chemical applications or constant weeding. Twice as much income from the same tract of land is a “good thing.”
In addition to being an architect, the author was a professional farmer for 17 years. During that period he was named U.S. Conservation Service Farmer of the Year. Those readers who wish to ask Richard Thornton questions about architecture, urban planning or Native American history may email him at Native Question@aol.com .