Terra preta Black Earth Stories

Black Wonder Earth modeled Rainforest: A reactor can convert plant waste into biochar. Makes soil fertile and long-term carbon binds. This also benefits the environment. Jet black and full of nutrients, so does the floor to about a tenth of the Amazon region. The plants grow there, much better than on the other surfaces that are light and low in nutrients. A few years ago, researchers explain the origin of terra preta-called black soil. You go up to 3000 years old waste, the aborigines left their settlements.


The chemical processes that led then stumbled to fertile soils, scientists hope installed specifically nährstoffarmem from biowaste such as hedge clippings and rice husks to produce a natural fertilizer. Moreover, while large amounts of carbon are fixed permanently. “If we can make the process more efficient and thus a large area to use, that would be also an important contribution to climate protection, which is much cheaper than other approaches,” the author writes. Several researchers are working to make this idea a reality.

The science Lerns succeeded the late 1990s explain the emergence of the black soils, which are found in the Amazon basin. Previously archaeologists had noticed a lot of pottery in the Terra Preta soils, which pointed to a significantly higher culture than current peoples of the rainforest. To find out whether not only the pieces, but also the entire black earth soils go back to the people, the researchers then developed new analytical methods to find substances that comes from cholesterol in the intestine and can survive in the soil for centuries. The scientists were able to show in the black soil samples greater amounts coprostanol. It was clear they had to have originated from human excrement.

When the researchers also examined the mass char particles, they found the explanation for the fertile soil in the middle of otherwise barren Amazon underground: “Apparently, the Indians had their waste, including feces and interspersed with angekohltem wood ashes of cooking fires around the municipal landfills. “Especially the charcoal pieces are crucial for the fertility of black soil. They consist almost entirely of carbon and have a very large surface, because they are covered with countless tiny holes. “The large surface area keeps nutrients, water, important for soil fertility and micro excellent air tight,” explained the researchers. The nutrients in turn come from the interspersed with fish bones, bones and even feces household wastes, which have decomposed in the soil slowly.

The Terra Preta soils are nothing more than rife with plenty of charcoal compost. And because the wood remains in the tropical climate hold for centuries, the floors are also another 500 to 3000 years after its creation extremely fruitful. “Presumably, the Indians eventually discovered that their crops at this former garbage heap grew much better than on the barren soil of the rainforest, which they had previously been cleared,” the scientists say.

What has worked for thousands of years in the Amazon rainforest should, with the technical possibilities of the 21st Century also be possible on the poor sandy soils in northern Germany, hopes the Halle researchers.

He and his staff rely on a process called pyrolysis. This plant residues are heated to temperatures of around 800 degrees Celsius. Volatile compounds such as alcohols, hydrocarbons or organic acid as a gas leak in the heat. What remains is a kind of skeleton of the former plant, which consists almost entirely of pure carbon. These “Biochar” is very porous, because the leaked gases leave countless tiny holes. It is thus similar to the charcoal, which has the Terra Preta soils made so fertile.

In Germany there are now two companies selling such pyrolysis plants. “Pyreg” offers smaller plants that produce about 350 tons a year biochar, while “Carbon Terra” is building a reactor that can be coupled together to much larger units. The trick with these systems is the energy balance: These gases are burned and give it more power than needed for the 800 degrees of the pyrolysis reaction. Such a reactor needs although no energy but can even produce heat or electricity. However, the plants must be constructed and operated – the bottom line is, pyrolysis have hardly counted. Then, the author draws on Biochar Research Centre. One should not forget, he writes that this logistical challenges: the storage of large amounts of organic waste on the transport to and from the plant up to the incorporation of biochar into the soil.

The same problems are there in the second method, the organic waste to make biochar, the “hydrothermal carbonization”. There green waste is also heated and treated also under high pressure in order to remove volatile components and to increase the carbon content. To prepare soil by means of pyrolysis, the scientists recommend that produce biochar from nutrient-poor plant waste such as hedge clippings. The rest of the nutrient-rich organic waste together with sewage sludge and sewage residues are added along with the biochar on large windrows. These are turned frequently and so well ventilated, the mixture is heated to temperatures of even around 70 degrees. “That is enough to destroy disease-causing microorganisms and weed seeds,” the scientists say. At the end you get compost that stores nutrients as good as the black soil of the Amazon.

In several countries, the scientists have compost mixed with lean sandy soils. The best fertilizer effect achieved while large quantities of 20 tonnes of biochar per hectare, where conventional farmers could double their previous harvests in the best case, he says. Normally, the benefit is lower. On average, plants can increase productivity by ten to fifteen percent, research shows. The application seems nevertheless worthwhile. In Austria Biokohlekompost per tonne paid up to 120 euros, the researchers report. For conventional compost only a fraction of being achieved. Biochar is not only interesting as a nutrient carrier. Since they in soil and water very well, so it may help the plants to survive the climate change probably more common in spring and summer droughts.