This item came out last summer and is a report on a field trial using biochar in Australia. Most importantly they mixed biochar at the rate of ten tons per acre. This is equivalent to any likely protocol that will be used by farming over a ten to twenty year cycle with corn or bagasse or any other natural biomass source to achieve the same result..
The yield doubled over all obvious variations on soils that are known to be somewhat infertile and even slightly toxic. This confirms the contention that all soils can likely be optimized to full optimal fertility throughout the globe. This is an astounding idea. We already know it works in the impossible rainforest environment and now we know it can be used on the unforgiving semi tropical nutrient depleted Australian soils.
Prior work supporting this contention came from the work done on zeolites by the Cubans. Zeolites and carbon are also known, if activated, as solid crystalline acids. So it comes as no surprise that enrichment with a strong dose of char will reconstitute soil biome in way that strongly supports general fertility.
I have already suggested that at the subsistence level of agriculture, char can be distributed in hills, reducing the initial dilution with soil for maximum initial utility. The char itself can be made up in a drum, if the supply is small or alternately in an earthen kiln best made from corn stover using the root pads to build the outer shell.
In large scale operations with an industrial kiln available, it is likely best to convert a small sub field each year to full terra preta status.
As I have been posting, this soil revolution will optimize every farm field on earth and lead to a possible near doubling of global production just on the lands we now use. The real payoff will be in the tropics were this method, perhaps using earthen kilns, will allow tropical soils to be fully exploited rather than present slash and burn.
There are very few places on earth where maximum fertility is achieved. I likely live in one of them. But I have walked over many hungry looking fields and have seen many areas that screamed for fertility management. One memory was driving through Germany any seeing a lone straggling blackberry vine in the fencerow. Later that afternoon, my uncle showed me his prize blackberry vine in his garden. In the Fraser Valley, black berry vines inundate the empty spaces if given half a chance producing true impenetrable barbed jungles. Yet the climate is just as benign in Germany. The only difference is a thousand years of hard cropping.
In short, even without watering the deserts, the world can handle a population of ten to twenty billion with this knowledge.
Friday, June 01, 2007
New research confirms the huge and revolutionary potential of soils to reduce greenhouse gases on a large scale, increase agricultural production while at the same time delivering carbon-negative biofuels based on feedstocks that require less fertilizer and water. Trials at Australia's New South Wales Department of Primary Industries’ (DPI) Wollongbar Agricultural Institute show that crops grown on agrichar-improved soils received a major boost. The findings come at a time when carbon-negative bioenergy is becoming one of the most widely debated topics in the renewable energy and climate change community.
The Australian trials of 'agrichar' or 'biochar' have doubled and, in one case, tripled crop growth when applied at the rate of 10 tonnes per hectare. The technique of storing agrichar in soils is now seen as a potential saviour to restore fertility to depleted or nutrient-poor soils (especially in the tropics), and as a revolutionary technique to mitigate climate change. Moreover, agrichar storage in soils is a low-tech practise, meaning it can be implemented on a vast scale in the developing world, relatively quickly.
Agrichar is a black carbon byproduct of a process called pyrolysis, which involves heating biomass without oxygen to generate renewable energy. Pyrolysis of biomass results in the production of bio-oil, that can be further refined into liquid biofuels for transport (earlier post, on Dynamotive's trials). When the agrichar is consequently sequestered into soils, the biofuels become carbon-negative - that is, they take more carbon dioxide out of the atmosphere than they release. This way, they can clean up our past emissions. No other renewable energy technology has both the advantages of being carbon-negative while at the same time being physically tradeable.
The biochar sequestration technique is now confirmed to boost soil fertility while storing carbon long-term. New South Wales Department of Primary Industries' senior research scientist Dr Lukas Van Zwieten said soils naturally turn over about 10 times more greenhouse gas on a global scale than the burning of fossil fuels.
“So it is not surprising there is so much interest in a technology to create clean energy that also locks up carbon in the soil for the long term and lifts agricultural production,” he said.
The trials at Wollongbar have focused on the benefits of agrichar to agricultural productivity: “When applied at 10t/ha, the biomass of wheat was tripled and of soybeans was more than doubled,” said Dr Van Zwieten. This percentage increase remained the same when applications of nitrogen fertiliser were added to both the agrichar and the control plots. For the wheat, agrichar alone was about as beneficial for yields as using nitrogen fertiliser only. And that is without considering the other benefits of agrichar.
Regarding soil chemistry, Dr Van Zwieten said agrichar raised soil pH at about one-third the rate of lime, lifted calcium levels and reduced aluminium toxicity on the red ferrosol soils of the trial. Soil biology improved, the need for added fertiliser reduced and water holding capacity was raised. The trials also measured gases given off from the soils and found significantly lower emissions of carbon dioxide and nitrous oxide (a greenhouse gas more than 300 times as potent as carbon dioxide):