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The promisse of Biochar

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Terra preta is an ancient soil from Amerindian populations, and we have our knowledge of biochar from these ancient soils. The Promise of Biochar Research into the benefits of terra preta and biochar is one of the most exciting developments in science today. These benefits include enhancing soil fertility and virtually permanent carbon sequestration. Dr. Johannes Lehmann of Cornell University is one of the top researchers in this field. A Cornell professor, the first professor in the department of geology, in the 1870s traveled to Brazil and came back with stories about terra preta wonderfully fertile soils on the banks of the Rio Negro. Terra preta is the remnant of previous occupations of Amerindian populations starting at about 7,000 years before present, up until the arrival of the Europeans. These soils are very dark, black soils that are very organic matter-rich, very fertile; crops grow vigorously on them. So the exciting aspect of that is that in an environment that otherwise features very infertile soils under primary forests in the Amazon, there exists these very dark, very fertile soils that prevailed over hundreds to thousands of years up to present time. Although people may think that rainforest soils are fertile, they are actually among the least fertile soils on Earth. By adding black carbon or biochar to the soil, the Amerindians created terra preta and greatly increased soil fertility. This allowed for sustained agriculture. Brazilian sites show these manmade soils are up to 2 meters deep, and have remained fertile, biodiverse, and up to 70 times higher in carbon than surrounding soils, even after hundreds or even thousands of years, in spite of the intense rainfall and biological activity of the rainforest. How biochar was created in the past to produce terra preta is, of course, largely unknown. One way that this could have happened is using technologies that we also know from charcoal making. Piling up biomass and under the exclusion of oxygen smoldering, or thermally decomposing biomass into charcoal, or biochar. This could have been added to soil, and that is what we see today as terra preta. And this technology can be carried forward. This biochar can be added to soil now, and create these favorable conditions that we see terra preta still has after hundreds to thousands of years. pyrolysis Today, we can create biochar using the process of pyrolysis. During pyrolysis, biomass is heated above a certain point that it spontaneously decomposes into charcoal, or biochar. The offgases can be captured to generate energy. Typically about 50% of the biomass is driven off to create the energy. The other 50% are retained in this very durable form of carbon called biochar. And this biochar can be returned to soil, to the very soils where we obtained our biomass from, thereby creating environmentally friendly bioenergy systems. Biochar improves soil in many different ways. It retains nutrients for plants that would otherwise be lost by leaching or to the atmosphere. It enhances microbiological activity, retains water, and increases crop yields. Dr. Lehmann’s student, Cristoph Steiner, has tested biochar’s effect on crop yield as shown in this recent BBC documentary. Inspired by the ancient Amazonians, Johannes Lehmann’s student, Cristoph Steiner, decided to find out exactly what effect ancient slash and char methods could have. So he has planted a series of experimental plots; some with added charcoal, some without. The experiment is still not finished, but already the results have been amazing. On this plot we see what happens if we follow the traditional slash and burn technique. After the first harvest already there is nothing growing any more, and we have here now the third harvest. Here on this plot we applied mineral fertilizer but that is not very satisfying. If you look on this there’s almost no yield, almost no grain. A family couldn’t live on this. That is not satisfying yield. In comparison, though, a plot where we applied additional charcoal there we can see that the yield is much bigger. So there is corn. And this is a plot where we applied charcoal and mineral fertilizer. In this combination last harvest we had an increase in crop production of 880% in comparison to mineral fertilizer without charcoal. An 880% increase in yield is almost miraculous. Charcoal seems to hold the nutrients in the soil, preventing them from being washed away by the rains. It’s a simple trick, but one that Steiner believes could be the key to breaking the destructive cycle of slash and burn. And so reducing the pressure on the rainforest. carbon sequestration Unlike other organic matter that can be added to soil, biochar remains in soil for very, very long periods of time and offers the opportunity to truly sequester carbon in soil. If linked to a sustainable biomass production, the addition of biochar withdraws atmospheric carbon dioxide and locks it up in the soil for very long periods of time. The very interesting aspect of pyrolysis with the biochar returned to soil, is that by producing the energy through pyrolysis, you retain about fifty percent of your carbon that you invested in producing the bioenergy in this very durable form of biochar. That means that half of your carbon cycle that you would normally return to the atmosphere you can divert into a much slower-cycling biochar cycle. And that creates the opportunity to design a bioenergy system that is actually not only carbon neutral, as most bioenergy systems claim to be, but actually carbon negative. So this creates an opportunity for bioenergy to be carbon negative. If bioenergy systems can be carbon negative, then producing biochar may be one of the most effective ways to fight global warming. Biochar technology, even linked to bioenergy production, can be realized on multiple levels. It can be done on very, very small level. There are small ovens and stoves - cookstoves - available that work on this technology, that are heating one pot of water to boil your rice. As well as on large power plants that would power whole industrial park or a small town. So this technology of biochar production can be realized in a small-farmer setting as well as in large production systems. biochar and climate change A biochar system is so appealing to both the politicians, as well as the farmers as well as the scientific community, because it is a comprehensive carbon management tool that helps alleviating our energy problems, as well as managing our infertile soils, as well as contributing to the mitigation of climate change.­­ How can biochar help to solve the problem of climate change ? If we enriched the soil in all the world’s cultivated farmland with biochar, we could remove and sequester all of the excess carbon dioxide in the atmosphere. The ancient terra preta soils of Brazil have inspired today’s scientists and farmers to see biochar as one of the most promising ways to combat global warming and improve soil fertility. biochar on the farm My name is Josh Frye. I am from Wardensville, West Virginia. I’m a poultry farmer. I raise 800,000 birds a year. At 800,000 birds a year that’s a lot of manure. I have the unit here to replace propane usage on the farm. This unit will produce biochar from chicken manure. I mean…you say “biochar” to somebody around here and they just look at it like: “what’s that?” You know…I mean they’re all used to chicken litter as fertilizer and so biochar is a whole other world. Like the new age fertilizer. I pretty much operate this unit single-handedly. I dump the litter into the hopper. Ah…the litter goes into the gas fire gets heated up. I use the heat byproduct from the unit to provide heat for the poultry. And the byproduct of the unit is a carbon-rich biochar. The value of the biochar has proven to be way more than I anticipated. My neighbor used some biochar in his pasture and the growth of the pasture was outstanding. The value of the unit to me as a farmer is twofold. One is to offset the heat and the cooling down I need for the birds. The other is to provide a very valuable fertilizer in the form of biochar, which is also a carbon sequestration media that can be used to capture carbon out of the atmosphere. I had a waste product that was not valuable, and now I have a product that is very valuable in the form of biochar. For more information contact the International Biochar Initiative: A Lily Films Production c 2008

Video Details

Duration: 11 minutes and 32 seconds
Country: Brazil
Language: English
Producer: Lily Films / International Biochar Initiative
Director: Deborah Koons Garcia
Views: 4,555
Posted by: cellopedroso on Mar 27, 2010

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