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Making Soil from Oil


Duane Pendergast


It’s said that it is an ill wind that blows no good. The prospect of disastrous global warming caused by emissions from fossil fuel use has aroused an ill wind of hurricane proportions. Many believe the planet is doomed if we don’t reduce our energy use and otherwise mend our wasteful ways. Scientists, environmentalists, engineers and politicians are frantically searching for and proposing solutions. Many proposals, particularly those most vigorously promoted, are band-aid fixes, not long term solutions.

Out of all this frenzied activity, there is one approach that serendipitously promises to not only manage fossil fuel emissions, but to improve and extend our agricultural land. It turns out the seed’s of such a system were planted in the Amazon jungle many hundreds or thousands of years ago. Natives of the area inadvertently captured carbon dioxide from the atmosphere with growing plants and deposited some of the carbon content in the soil, with a variation of slash and burn agriculture. Remarkably fertile soil, now known as “terra preta” was formed. It is still there today, long after that productive society disappeared.

Amazingly, fossil fuel emissions might thus become a resource instead of a liability. To make this happen humans could develop agricultural systems to convert part of the plant growth they control into charcoal and add it to soil. Developing evidence indicates charcoal in soil supports biotic processes which increase soil productivity. That in turn promotes still more growth creating a feedback system enhancing the ability of the biosphere to remove carbon dioxide from the atmosphere.

In essence we may be able to “make soil from oil” and other fossil fuel resources as the earth evolves through the fossil fuel age to a new state of sustainable abundance and plenty established by its human component.

Reinventing Terra Preta

Several years ago, I served as a representative of the Canadian Nuclear Association to Canada’s National Climate Change Process. I started thinking about ways to extend the role of nuclear energy as a carbon dioxide emission avoider, to a carbon sink creator. Diagrams of the carbon cycle show huge quantities of carbon have been retained in soils over the eons as well as in fossil fuels.  My agricultural colleagues focused on agricultural techniques to sequester more carbon in the soil. The "no till" technique which had evolved on the prairies was one way toward that goal as plant material including stalks and roots, are left on and in the soil. Composting was another soil enrichment technique cited by many that also sequesters some carbon. Those techniques are limited. Carbon bearing organic material in soil decomposes; producing and releasing greenhouse gases back to the atmosphere rather quickly.

Still, it seemed to me that nuclear energy could at least be used to help grow plants. Nuclear produced electricity could be substituted for water power - thus making water more readily available for irrigation. Perhaps nuclear energy could be used for water desalination and the production of fertilizers such as ammonia. This would help agriculture remove carbon dioxide from the atmosphere.

My first attempt to evaluate the potential of nuclear energy as a carbon sink enabler thus focused on the possibility of diverting water from northern to southern Alberta to expand irrigation. I found that half of the water from a major northern river would grow crops absorbing about 160 million tonnes of atmospheric carbon dioxide annually. I had an inkling, originating from my youth on a bush farm, that perhaps forest fires and charring of partially burned trees, as well as grass fires on the prairies, had played a role in soil formation since the last ice age. I started to investigate that possibility. I came across a few papers exploring soil structure using carbon 14 dating of charcoal or char samples in the soil going back hundreds and thousands of years. That indicates charcoal might be very durable and could provide a lasting carbon sink. I thus suggested - I thought tongue in cheek - in a presentation to the Canadian Institute of Energy on January 23, 2002, that if the carbon in that crop were converted to charcoal it would resolve more than half of Canada’s Kyoto commitment.

Unfortunately, I also found that just pumping the water to the 700 metres higher elevation of southern Alberta would take at least 12,000 MW of electrical energy. The massive investment in nuclear reactors, pumps, pipes, canals, and great expansion of irrigated land suggested a show stopper. So, to turn nuclear energy in concert with agriculture into a carbon sink something more was needed.

My search for knowledge took me to a seminal conference in Georgia in May of 2004. It brought together about 50 archaeologists, soil scientists, foresters and experts in energy. There my speculation that charcoal, or bio-char, might play a role in productive soil formation found already established independent support. Discoveries over a hundred year span in seemingly disconnected fields coming together in synergy generated profound excitement and a fascinating conference. It turned out my convoluted quest had taken me back to reinvent a potential means of managing carbon dioxide based on adaptation of natural processes.

Best of all, the process promises to build the planet’s soil resources, and thus its productivity, from the emissions of our fossil fuel use. That could free us from the doomsday scenarios of those who claim the planets capacity to support life is limited. It is thus worth pursuing in its own right, even if it turns out that carbon dioxide emissions do not significantly influence global warming.

Terra Preta now

The paucity of information just four or five years ago is gone. The current rush of ideas is too much for easy evaluation. Enthusiastic climate scientists, engineers, gardeners, and farmers from all over the world have discovered – and no doubt also reinvented - the terra preta concept and its potential linkage to managing greenhouse gases. New papers and articles in specialty technical magazines have been published. Even sober science magazines such as Nature and Scientific American have featured the concept in news articles over the past year.

Perhaps the best way to convey the growth of interest - and excitement - is to point readers to the newly established Terra Preta Discussion List and Website. Its goal is to provide the primary world web location for technical discussions on the intentional placement of charcoal in soil. Enthusiasts there have coined the term “neo terra preta” to describe modern systems to capitalize on the invention of Amazonian natives.

The site references many technical papers and discusses a vast array of topics related to the production and use of char from bio material to serve as an enhancement to soil and a carbon sink. One can explore the origins of the discovery of ancient civilizations and terra preta soils in the Amazon over a hundred years ago. Contemporary soil scientists explain possible beneficial effects of char in the soil. Engineers discuss various designs for the production of char, sometimes in conjunction with hydrogen and/or bio-oils for energy. It’s pointed out that humans already control a large fraction of the biospheres production of organic material. And it contains carbon far exceeding emissions of carbon from our use of fossil fuel. Farmers and gardeners are producing and using charcoal in experiments to evaluate the effects on crop yields.

Danny Day of the Eprida Foundation suggests, with almost evangelical zeal, that we are seeing the “stumbling steps of a brand new species evolved to stabilize this recurring imbalance” with reference to the drastic cycling between ice ages seen in the climate change record. He sees the burgeoning human population, including some three billion now impoverished farmers, as key to planetary survival and prosperity. Such optimism is very refreshing; contrasting sharply with the claims of some that mankind is but a form of plague proceeding blindly ahead to destroy the planet.

Neo Terra Preta

Enthusiasm and optimism are essential ingredients to move new technology forward. Still, solid science, research, and development will be needed to firmly form a basis for developing modern terra preta techniques.

Just browsing through the new wealth of information on the concept raises many significant questions. How will the air pollution from historical charcoal production techniques be managed? Could clean new charcoal production techniques be developed by industrial societies? Does charcoal really provide an environment conducive to the development of soil by enhancing biotic action? Soil scientist Henry Janzen, of Agriculture and Agri-Food Canada, points out that “soil organic matter is far more than a potential tank for impounding excess CO2; it is a relentless flow of C atoms, through a myriad of streams—some fast, some slow—wending their way through the ecosystem, driving biotic processes along the way” through the provision of energy and nutrients. What is the proper mix of durable charcoal and other organic material to provide a soil building environment? Is the application of charcoal to soil beneficial outside the tropics? How much can crop yields be increased? Can charcoal be combined with fertilizers in synergistic ways? How can energy required for charcoal production be integrated with other human energy needs?

Fortunately, the answers to such questions can be established by science. Optimism and enthusiasm are evolving toward the establishment of controlled experiments needed to provide solid evidence for the soil building potential of terra preta.

Neo Terra Preta in Alberta?

The bulk of evidence for the soil enhancing effects of charcoal comes from tropical countries. Similar soils have been found elsewhere. Indeed, Robert Maxwell (retired) of the British Columbia Ministry of Environment tells of the discovery of black, charcoal rich man made soils on Vancouver Island.

Dr. Marco Rondon, a scientist and native of Colombia now employed by Canada’s International Development Research Centre (IDRC), sees lead applications in the rehabilitation of degraded lands in the tropics and intensification of agriculture on hillsides of South America, Asia and Africa, where land is scarce and not very fertile. His concept extends that of terraced agriculture initiated in the Andes and elsewhere centuries ago.

Much remains to be done to confirm terra preta benefits, particularly in temperate climates. Alberta seems to have just the right conditions to spur such research. Google Earth shows large areas affected by mining the oil sands. Photos show total local devastation. That land’s soil will need to be re-established. Oil sands operations will proceed on a very long time scale. Evaluation and development of the terra preta concept could proceed in parallel. David Layzell of Biocap Canada Foundation thinks neo terra preta “is a very credible alternative - with significant potential for Canada”. Sustainable Development Technology Canada’s mandate includes the development of technology to sequester carbon from biomaterial while enhancing soil. Alberta legislation establishing the “Climate Change and Emissions Management Fund” provides for a potential source of funding. It seems all the elements needed to make a major contribution to temperate climate terra preta development could merge right here in Alberta. Perhaps one day, if global warming is really coming, land currently degraded by oil sand operations could become our breadbasket.

In Conclusion

Human ingenuity has already worked wonders to boost the life supporting productivity of our planet. Our development of agriculture and use of energy bear the major responsibility for that transformation. Doomsayers are telling us that tell us that resultant global warming will make earth uninhabitable. What delicious irony if it turns out that humans can turn a problem identified with their agriculture and fossil fuel use into an asset to remove limits to the planets future.


I thank my brother Bruce Pendergast and wife Bobbie Pendergast for their careful reviews and thoughtful comments.


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