By Dr. Miguel Providenti, Saskatchewan Research Council
energy
Biochar and
BIotechnology oLd And neW TecHnoLoGieS To SoLVe TodAY’S cHALLenGeS
biotechnology is recognized as a cutting-edge tool that may help society overcome two major challenges. by enhancing agricultural productivity, biotechnology can assist in feeding an increasing world population. And, by developing sustainable bioprocesses and bioproducts, biotechnology can lower dependence on non-renewable petroleum resources. Less well known is that biochar, a centuries old soil amendment technology undergoing a renaissance, is also being proposed as a solution to these challenges. That’s not all; biochar may also provide a way to mitigate climate change and diversify economies. What is biochar and how can it do all this?
Biochar: charcoal by any other name Charcoal is considered one of the oldest processed fuels known to mankind. It is produced by heating biomass like wood in low-or-zero-oxygen environments. Charcoal can be produced in a variety of ways, from low-tech earth mound kilns and buried pits to higher-tech pyrolysis units. In North America, charcoal is associated with barbeques, but charcoal was used as cleaner-burning fuel to cook food and for iron smelting. Many are also familiar with activated carbon, which is used to filter and purify water. When it is applied to soil, charcoal takes on a new function, soil amendment and a new name, biochar. 20 BIOTECHNOLOGY FOCUS JULY/AUGUST 2010
Prior to the arrival of Europeans, biochar was used by Amerindian farmers in the Amazon region as a soil management technique that appears to have supported complex civilizations as they developed. Evidence of these ancient practices can still be found in Amazonian Dark Earths, also known as Terra Preta, Portuguese for cooked earth.
Promising features and potential new applications Biochar and biochar-producing systems have many features that suggest a promising future for this old product.
Soil management Biochar stimulates soil microorganisms’ activity. It may lower fertilizer other agrochemical inputs while improving water use efficiency, since it reduces chemical run-off and retains water. In richer soils, biochar’s productivity benefits may be subtle or only observed during a drought or lower than normal precipitation, but in degraded or nutrient-poor soils, productivity improvement can be dramatic.
And, because biochar is stable, one application’s benefits are felt for years. Climate change mitigation Regular soil carbon derived from compost or other organic matter can be converted to carbon dioxide by soil microorganisms over months to years. In contrast, biochar carbon is stable for centuries to millennia. Given this longevity, biochar has been suggested as a method for sequestering atmospheric carbon dioxide captured during normal plant photosynthesis in a process known as biosequestration. Biochar also lowers soil emissions of other potent greenhouse gasses like nitrous oxides and methane. Diversify economies Biochar can be produced from a wide variety of feedstocks and biochar production may provide alternative outlets for biomass and residues from a variety of sectors. Obvious ones include agriculture and forestry, but additional sources include biomass from industry and municipalities, which would have the additional benefit of diverting organic matter streams away from landfills. An added bonus is that when biochar is produced, the energy it releases can be used for heating, which reduces the reliance on fossil fuels. Furthermore, biomass can be economically transported in an approximate range of 200 km. Because of this continued on page 22
