Terra preta "is certainly a term that - as yet largely unknown - will be familiar to many people in a short time. The mere translation from the Portuguese "Black Earth" is already an indication of what it could go, but we want to go back a little further in order to shed light on the whole.
records of the English conquistadors in the 16th Century through its expansion into the Amazon region threw at the historians have always been many questions. There, that is reported by a huge number of Indians to which the conqueror will be met in the jungle. The problem lies in the question, as so many people would be able to feed. As is known, the Amazon rain forest is actually very barren because the soil consists of a nutrient-poor, so-called Oxisol. Rodet to the forest and creates the fields, they must be exhausted after a few years and you have to clear a new piece of forest to agriculture can continue to operate.
There was thus a contradiction between the otherwise reasonably credible reports of the conqueror and the experience of today. Archaeologists were able to finally solve the mystery. They kicked in the Amazon region actually the remains of numerous and sometimes large settlements, high population density occupied. The reports seemed so agree. But what about the food, because so many people could not be fed solely by collecting wild fruits and hunting of animals?
The answer to this question was obtained than is the environment of the settlements studied in detail. There they came upon a very dark ground, which looked completely different, rather than the normal reddish forest floor and the surroundings of the settlements covered in a depth of up to two meters. This soil had to have been created specifically by the Indians, because it contained large quantities of fired clay fragments that could not have come naturally from there. A chemical analysis revealed then final clarity: most striking feature of this soil is the high content of charcoal. Next door you can fish waste and sewage residues. The charcoal colored soil dark, where he got his name: Terra preta .
growth experiments with this soil showed very quickly a surprisingly high fertility. Compared to the normal forest floor showed a much higher crop yield (up to ten times!) And it was observed no leaching of nutrients.
The reasons for this are relatively easy to accomplish: charcoal has to mineral soil and humus is a greatly enlarged Surface, which can be up to 800 square meters per gram. The manufacturing process (which we discuss later in detail) from vegetable source material are in fact very many channels and pores, which increase the surface of the coal. In the pores can be both water and plant nutrients are stored. They also form an ideal breeding ground for bacteria in the soil which are essential according to recent findings for healthy plant growth.
moisture and nutrients are then released slowly and by the activation of soil life, the availability to the plants improved. The interactions between soil bacteria and the root network of plants are the way, are poorly understood. We only know that they have a tremendous importance for the growth of the plants have. There is still much room for further research!
by the deliberate introduction of fish waste (phosphorus) and fecal (nitrogen and minerals), then the Indians have a nearly ideal substrate for growing food crops created. This explains how it was possible to feed on an otherwise relatively barren soil, a large number of people.
addition to the positive effects on plant growth Terra preta offers yet another advantage of the first perhaps even outweighs by far: carbon storage, often under the technical term "sequestration" discussed. Terra preta is in fact some 2000-4000 years old. Nevertheless, the carbon content is still high. Obviously, the carbon can then several thousand years are stored.
What options here and can give the significance of this aspect in your environment, we will discuss in the next episodes of this series of articles.
to questions and comments will be glad to reply to our email address:
terrapreta@web.de
Energy AG go and Environment, Working Group Terra preta
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