It turns out that ``Amazonian black soil created by ancient people'' boosts the growth of grass and trees



In some areas of the Amazon River Basin, there is a rich, black soil called `

`Terra Preta' ' created by indigenous peoples. Research results have shown that the growth of trees and grasses can be boosted by using Terra Preta.

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https://www.frontiersin.org/articles/10.3389/fsoil.2023.1161627/full



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The soil in the Amazon River Basin is not suitable for cultivation as it easily loses nutrients due to strong sunlight and heavy rain, but it is known that some areas have moist, black soil that is rich in nutrients. This soil, called terra preta, is not naturally formed, but is thought to be man-made soil created by indigenous peoples between 450 BC and 950 AD. The indigenous people created terra preta, which is rich in nutrients and organic matter, by depositing charcoal used for cooking and garbage incineration, animal bones, pottery shards, and compost over generations.

A research team led by Luis Felipe Zagatto, a graduate student at the Agricultural and Nuclear Center at the University of São Paulo in Brazil, conducted an experiment to recreate a situation in which ``soil containing terra preta became pasture, and then the forest recovered.'' The we.



First, the research team prepared Terra Preta soil collected in

Amazonas state , Brazil, and soil from an agricultural school in São Paulo state as a control group. Then, we prepared 36 4-liter pots, ``a pot with only control soil,'' ``a pot with 80% control soil and 20% terra preta,'' and ``a pot with 100% terra preta.'' ” I made 12 pieces each.

These pots were placed in a greenhouse at 34 degrees Celsius, which mimics an environment where global warming is more advanced than in modern times, and seeds of Urochloa brizantha (palisades grass), a common grass in Brazil, were planted. . Palisade grass is grown in pots for 60 days, then harvested leaving only the roots, which are then planted with forest tree species such as Ambay pumpwood , Peltophorum dubium , and Cedlera fissilis . I grew it for 90 days.

Grass was cut 60 days after seeds were planted, and trees were cut 90 days after planting, and root length, dry mass, and growth rate were measured. In addition, during the experiment process, nutrients such as organic matter and minerals contained in the soil, as well as the diversity of microorganisms in the soil, were measured.

At the beginning of the experiment, pots with more terra preta were richer in nutrients, as expected. After growing the plants, the nutrients in both pots were used for plant growth and decreased, but the pots with more Terra Preta still had more nutrients remaining. Additionally, throughout the experiment, pots containing 20% or 100% Terra Preta had higher bacterial and archaeal biodiversity.

The amount of terra preta contained in Daoshu also had a great effect on the growth of grass and plants. The dry mass of grass increased 3.4 times in pots containing 20% Terra Preta and 8.1 times in pots containing 100% Terra Preta compared to the target soil. Additionally, Peltophorum dubium and Cedrella fissilis grew 2.1 to 6.3 times higher than the target soil when grown in pots containing Terra Preta, and Ambay Pumpwood only grew in pots containing 100% Terra Preta. The research team reports.

The photos below, from left to right, are a pot with 100% Terra Preta, a pot with 80% control soil and 20% Terra Preta, and a pot with only control soil. You can see that Cedrela fissilis planted at the same time grows better as the soil contains more terra preta.



Based on the results of this experiment, the research team concluded that Terra Preta promotes plant growth. 'We show that using Terra Preta, which contains beneficial microbial and archaeal microbiota and high levels of nutrients, promotes grass and tree growth,' said Zagat. 'Applying our knowledge of the 'components' that make Terra Preta such a rich soil could help speed up ecosystem restoration projects.'

Tsai Siu Mui , a co-author of the paper and a professor at the University of São Paulo's Agricultural and Nuclear Center, said, ``Terra preta has been accumulated over thousands of years, and when used in nature, It will take the same amount of time to reproduce.We recommend not using Terra Preta itself, but rather copying its properties, especially its microorganisms, for use in future ecosystem restoration projects. That's what I do.''

in Science, Posted by log1h_ik