In 1542, a detachment of Spanish conquistadors, led by Francisco de Orellana, set sail on the Amazon
downstream from the tributary of the river in the region of present Peru. In total, they sailed more than 5,000 kilometers with stops along the banks of the river, sometimes moving deeper into the territory.
However, from the numerous tropical diseases they soon almost all died.
However, Orellana remained alive and returned to Spain. In his diaries, he reported that in this expeditionthey saw a huge country, with a large population, huge cities linked together by good causeways among the jungle, with markets abounding in food and numerous gold products. Orellana called this country El Dorado (Eldorado). Orellana assembled a new expedition and in 1546 tried to return to this country, but due to lack of funds the expedition was equipped badly, there was not enough food, weapons and people. After reaching the mouth of the Amazon, the expedition began to climb upstream. Members of the
expedition suffered from tropical diseases, food shortages, were subjected to constant attacks by the
Indians. In November 1546, Francisco de Orellana also died of the disease.
The next expedition was sent by the Spaniards to the Amazon region only a century later, and, alas, no
fairytale country was found. It was found several small tribes of American Indians engaged in hunting
and fishing, and apart from the jungle they saw nothing. Then, the search for the mythical country of
Eldorado continued, but they did not lead to any results either. So in the history of Eldorado, there was
only the saying “the mythical country of Eldorado”, as saying about something fantastically rich, but not
existing in fact. However, at the end of the 20th century it became clear that Eldorado still was existing in fact. And everything was as Orellan described. Primarily, the attention of soil scientists (and among them the first was Wim Sombroyek from Holland) attracted plots of unusually fertile land in Peru, called Terra Preta by Indians, which in Spanish means “Black Earth. The fact is that the land in the Amazon (like all tropical lands) is very infertile. These are red and yellow soils with a lot of oxides of aluminum and other metals (the so-called xyzols), on which practically nothing grows (from agricultural crops), except for rare local weeds.
However, theTerra Preta lands were strongly black and unusually fertile. They gave (and now give) a
good harvest even without any fertilizers. This land turned out to be so good that local farmers began to
export it, as a land for flower pots. When Wim Sombroek arrived in Peru and began to explore this land,
local farmers told him an even more amazing thing: that the top layer of the land they were renting from
Terra Preta (about 20 cm) in 20 years is completely restored by itself. Sombroyek made measurements of
the thickness of the earth (which turned out to be on average 70 cm) and in the future this fact was
confirmed: the land of Terra Preta itself is being restored. The recovery rate is 1 cm per year. It is also surprising that this black earth is very fertile, and the red or yellow earth is only a few dozen meters from it almost completely infertile.
When the chemical analysis of these lands was carried out, it turned out that they are absolutely identical in chemical composition. And geological analysis showed that these soils have the same geological origin. The difference was only in one thing: the black earth contained charcoal in abundance, from 10% to 30%. An assumption has appeared that these black soils are of anthropogenic origin. Radio-carbon analysis showed that the age of this charcoal is more than 2000 years. Therefore, on this place there was an ancient civilization! Excavations of this land showed that clay crocks are often found in it. But can it be just a site of ancient Indians, if the total area of this land reaches several hundred hectares? And if this is just a settlement, then what did they eat among the barren jungle? In general, a lot of questions have arisen, causing scientists to be perplexed. Later on, in the Amazon basin, 20 large tracts of Terra Preta land were discovered, and many small ones, with a total area equal to the area of France. According to scientists, about 3 million people lived on this territory. It was a developed civilization with a complex social structure. Ethnographic expeditions confirmed that among the many tribes of the Amazon Indians, customs, traditions and concepts that can exist only in large civilizations have survived, and which do not occur among small tribes (as unnecessary). Apparently, these are the remnants of that civilization. Where did the civilization go? According to one of the assumptions of scientists, the expedition of Francisco de Orellan brought with them viruses to the Amazon Indians, to which the Indians had no immunity, and so the Indians died soon from a mass epidemic. Then the jungle quickly occupied this territory. Therefore, 100 years after Orellan, Europeans did not find anything.
However, modern aerial photographs have allowed to see that all these patches of Terra Preta are
connected among themselves by numerous roads that the Indians laid in the jungle with the help of
embankments, and which, after the civilization end, were quickly absorbed by the jungle. Radio-carbon analysis showed that some sites are of 4000 and more years old. Consequently, this civilization existed on extremely infertile tropical lands for more than 4000 years and could feed itself, and that is why the
interest in Terra Preta all over the world is increasing more and more. Why are these sites of fertile land still now, even 400 years later, remain fertile even without the introduction of fertilizers, either organic or mineral?
To date, it was found that the Indians added the usual charcoal into the land, which they received from
trees growing in abundance in the jungle. This is very different from the current slash-and-burn
agriculture used by some farmers: the forest is burned, then it is used for several years and then it is left again until the trees grow on it again. This system is not very effective. However, the use of chemical fertilizers on tropical soils gives even less results. Charcoal is chemically inert. Why does it give such a strange effect – makes the soil fertile for millennia, and even without any fertilizers?