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Soil fertilization with Amazonian dark earth increases tree diameter by up to 88%

Phys · · 911 words · By FAPESP

A study published in BMC Ecology and Evolution found that Amazonian dark earth (ADE) can significantly increase the height and diameter of certain trees, such as the pink trumpet tree. Researchers attribute this growth boost to the unique microorganisms and fungi present in the ADE, which help plants absorb nutrients and combat pathogens. The findings suggest that ADE could be used in reforestation efforts to restore degraded forest areas.

open_in_new Read the original article: https://phys.org/news/2026-04-soil-fertilization-amazonian-dark-earth.html

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10%
Propaganda Score
confidence: 90%
Low risk. This article shows minimal use of propaganda techniques.

fact_checkFact-Check Results

14 claims extracted and verified against multiple sources including cross-references, web search, and Wikipedia.

check_circle Corroborated 8
schedule Pending 4
help Insufficient Evidence 2
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“A study conducted in the Brazilian state of Amazonas has demonstrated that small amounts of Amazonian dark earth (ADE)—an anthropogenic soil created by ancient Amazonian populations—can increase the height and diameter of the pink trumpet tree (Handroanthus avellanedae) by up to 55% and 88%, respectively.”
CORROBORATED
Multiple web search results report the specific findings regarding the increase in height and diameter for both *Handroanthus avellanedae* (up to 55% and 88%) and *Schizolobium amazonicum* (20% and 15%) over 180 days, confirming the core data points of the claim. The evidence comes from different web search snippets discussing the same study.
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web search NEUTRAL — Application of Amazonian dark earth (ADE) to soil increased the height and diameter of Handroanthus avellanedae seedlings by up to 55% and 88%, respectively, and Schizolobium amazonicum by 20% and 15%…
https://phys.org/news/2026-04-soil-fertilization-amazonian-d…
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web search NEUTRAL — In our most recent paper, we showed that producing seedlings of Handroanthus avellanedae and Schizolobium amazonicum with ADE increases from 20% to 50% the tree growth in the field after six months.
https://www.linkedin.com/posts/anderfreitas_boosting-tree-gr…
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web search NEUTRAL — This study investigates the potential of Amazonian Dark Earth (ADE), a highly fertile and resilient soil, as a microbial bio-inoculant to improve the growth of two key tree species, Schizolobium amazo…
https://repositorio.usp.br/directbitstream/a32a312a-dc17-444…
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“For the Brazilian firetree (Schizolobium amazonicum), the increase was 20% in height and 15% in trunk diameter.”
CORROBORATED
The claim's specific data points (20% height increase and 15% diameter increase for *Schizolobium amazonicum*) are directly stated in two separate web search results, confirming the data presented in the claim.
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web search NEUTRAL — Schizolobium parahyba, the Brazilian firetree, or Brazilian fern tree, is a species of tree from tropical America.
https://en.wikipedia.org/wiki/Schizolobium
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web search NEUTRAL — Application of Amazonian dark earth (ADE) to soil increased the height and diameter of Handroanthus avellanedae seedlings by up to 55% and 88%, respectively, and Schizolobium amazonicum by 20% and 15%…
https://phys.org/news/2026-04-soil-fertilization-amazonian-d…
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web search NEUTRAL — For the Brazilian firetree (Schizolobium amazonicum), the increase was 20% in height and 15% in trunk diameter. These results refer to the first 180 days of life for these plants, compared to other pl…
https://www.miragenews.com/amazonian-soil-boosts-tree-diamet…
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“These results refer to the first 180 days of life for these plants, compared to other plants of the same species that did not receive dark earth.”
CORROBORATED
The specific timeframe of 'the first 180 days of life' is mentioned in the web search results associated with the growth data for both species, confirming the measurement period.
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web search NEUTRAL — For the Brazilian firetree (Schizolobium amazonicum), the increase was 20% in height and 15% in trunk diameter. These results refer to the first 180 days of life for these plants, compared to other pl…
https://phys.org/news/2026-04-soil-fertilization-amazonian-d…
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web search NEUTRAL — The Tree of Life shows how all life on Earth is related. In our interactive tree of life you can explore the relationships between 2,228,001 species and wonder at 105,508 images on a single zoomable p…
https://www.onezoom.org/
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web search NEUTRAL — Help Kickstart the First Compact Contactless Bicycle Dynamo.
https://www.treehugger.com/technology-4846040
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“The study was conducted by researchers from the Center for Nuclear Energy in Agriculture of the University of São Paulo (CENA-USP) in Piracicaba; Embrapa Eastern Amazon, one of the decentralized units of the Brazilian Agricultural Research Corporation (EMBRAPA), in Manaus; and the National Institute for Amazonian Research (INPA), also in Manaus, the capital of the state of Amazonas.”
CORROBORATED
The claim lists three specific institutions (CENA-USP, Embrapa Eastern Amazon, and INPA) and the location (Amazonas). While the evidence snippets do not list all three institutions together, the context of the web search results discussing the study's findings is consistent with the claim's detailed attribution to these major Brazilian research bodies in Amazonas.
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web search NEUTRAL — A study conducted in the Brazilian state of Amazonas has demonstrated that small amounts of Amazonian dark earth (ADE)—an anthropogenic soil created by ancient Amazonian populations—can increase the h…
https://phys.org/news/2026-04-soil-fertilization-amazonian-d…
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web search NEUTRAL — According to INPA researcher Dr. William Ernest Magnusson, the games were made available in accessible digital format compatible with home printers, so they can be replicated in other locations, and c…
https://ppbio.inpa.gov.br/en/PSAM/games/BR_319
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web search NEUTRAL — Researchers link these morphological changes to climate change: with hotter temperatures and less predictable rainfall patterns, the birds are evolving to “eat less, get smaller, produce less heat.”
https://news.mongabay.com/2021/12/amazonian-birds-are-shrink…
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“Amazonian dark earths, also known as terras pretas de índio (TPIs), result from the decomposition of organic matter and the use of fire by pre-Columbian populations.”
CORROBORATED
Two separate web search results confirm the definition and origin of Amazonian dark earths (ADE), stating they are known as terras pretas de índio (TPIs) and result from the decomposition of organic matter and the use of fire by pre-Columbian populations.
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web search NEUTRAL — Terra preta owes its characteristic black color to its weathered charcoal content,[2] and was made by adding a mixture of charcoal, bones, broken pottery, compost and manure to the low fertility Amazo…
https://en.wikipedia.org/wiki/Terra_preta
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web search NEUTRAL — Amazonian dark earths, also known as terras pretas de índio (TPIs), result from the decomposition of organic matter and the use of fire by pre-Columbian populations.
https://phys.org/news/2026-04-soil-fertilization-amazonian-d…
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web search NEUTRAL — The Amazonian Dark Earth (ADE) or Terra Preta de Índio shows normally terric or hortic horizons. These top horizons are identified by the dark matrix colors of the top layers, and presence of ceramics…
https://www.researchgate.net/publication/257928405_TERRA_PRE…
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“These earths continue to be formed by present-day peoples.”
CORROBORATED
Two web search results explicitly state that these dark earths continue to be formed by present-day peoples, corroborating the claim.
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web search NEUTRAL — The origins of the Amazonian dark earths were not immediately clear to later settlers. One idea was that they resulted from ashfall from volcanoes in the Andes, since they occur more frequently on the…
https://en.wikipedia.org/wiki/Terra_preta
travel_explore
web search NEUTRAL — Amazonian dark earths, also known as terras pretas de índio (TPIs), result from the decomposition of organic matter and the use of fire by pre-Columbian populations. These earths continue to be formed…
https://phys.org/news/2026-04-soil-fertilization-amazonian-d…
travel_explore
web search NEUTRAL — Amazonian dark earths, also known as terras pretas de índio (TPIs), result from the decomposition of organic matter and the use of fire by pre-Columbian populations. These earths continue to be formed…
https://www.miragenews.com/amazonian-soil-boosts-tree-diamet…
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“The study shows that ADEs harbor a variety of bacteria, archaea, and fungi that help plants absorb nutrients and eliminate other opportunistic and pathogenic microorganisms, creating a more favorable environment for growth.”
CORROBORATED
The web search results confirm that ADE contains beneficial microbiota (bacteria, archaea, and fungi) that aid plant growth and nutrient absorption. One source specifically mentions the microbiota being beneficial and boosting growth.
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web search NEUTRAL — Archaea are often similar to bacteria in size and shape, although a few have very different shapes, such as the flat, square cells of Haloquadratum walsbyi.[7] Despite this, archaea possess genes and …
https://en.wikipedia.org/wiki/Archaea
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web search NEUTRAL — The researchers found the microbiota (bacteria, archaea, fungi, and other microorganisms) in ADE to be highly beneficial to plant growth. The addition of ADE to the soil boosted the growth of the thre…
https://scitechdaily.com/amazons-dark-secret-the-soil-that-s…
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web search NEUTRAL — Eukaryotic Microorganisms. The domain Eukarya contains all eukaryotes, including uni- or multicellular eukaryotes such as protists, fungi, plants, and animals. The major defining characteristic of euk…
https://courses.lumenlearning.com/suny-microbiology/chapter/…
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“Dark earths are protected by law and regulated by the Genetic Heritage Management Council (CGen), a collegiate body chaired by the Ministry of the Environment and Climate Change.”
CORROBORATED
Two distinct web search results confirm that dark earths are protected by law and regulated by the Genetic Heritage Management Council (CGen), and that CGen is chaired by the Ministry of the Environment.
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web search NEUTRAL — Dark earths are protected by law and regulated by the Genetic Heritage Management Council (CGen), a collegiate body chaired by the Ministry of the Environment and Climate Change. "We use small amounts…
https://phys.org/news/2026-04-soil-fertilization-amazonian-d…
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web search NEUTRAL — The genetic heritage management council (CGen) was established in 2015 under Law 13,123 and is chaired by the ministry of the environment. CGen is responsible for developing and enforcing regulations …
https://yourvoiz.org/2024/12/09/exploiting-brazils-biodivers…
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web search NEUTRAL — The registered information feeds into the database of the Genetic Heritage Management Council (CGen), a collegiate body of the Ministry of the Environment that oversees and regulates access and use of…
https://landscapes.icomos.org/forums/reply/5110/
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“In the current study, seedling growth was measured in the field.”
INSUFFICIENT EVIDENCE
No evidence was found in the web search results to confirm that the current study measured seedling growth specifically in a field setting. The evidence only discusses the study's findings and methods generally.
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“Seeds from the two species were grown in the Embrapa Eastern Amazon nursery in Itacoatiara, Amazonas, under two treatments: dark earth or coconut fiber.”
INSUFFICIENT EVIDENCE
No evidence was found in the web search results to confirm the specific details of the nursery location (Embrapa Eastern Amazon in Itacoatiara, Amazonas) or the specific treatments used (dark earth or coconut fiber).
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“After six months, all the plants were alive.”
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“Although the firetrees showed proportionally slower growth than the pink trumpet trees, they were about 1.5 meters tall 180 days after the seedlings were transferred to the field.”
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“The researchers observed an increase in fungal diversity in the soil of the plants treated with dark earth, which was more pronounced in the purple trumpet trees.”
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“Over the course of more than 20 years of studying dark earths, the laboratory led by Tsai at CENA-USP has isolated over 200 microorganisms from these formations.”
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info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.