Table of Contents
The Hidden Potential of Amazonian Soil for Enhancing Tree Growth
Researchers in Brazil have undertaken an in-depth study of soil from the Amazon, known as Amazon Dark Earth (ADE), with the objective of leveraging its unique properties for biotechnological applications aimed at the effective rehabilitation of ecologically compromised zones. Image credits: Luís Felipe Zagatto/CENA-USP
Scientific evidence suggests that Amazon Dark Earth (ADE) has the capacity to increase tree growth rates up to six times higher than that of ordinary soil. The investigation revealed that saplings planted in soil enriched with ADE experience significantly faster growth when compared to those in control soil samples.
Known scientifically as “terra preta da Amazônia,” Amazon Dark Earth (ADE) is found to accelerate the growth of trees and improve their overall health, as reported in a journal article featured in Frontiers in Soil Science.
Luís Felipe Guandalin Zagatto, a graduate student at the University of São Paulo’s Center for Nuclear Energy in Agriculture (CENA-USP) and co-author of the paper, stated that ADE is abundant in essential nutrients and fosters microbial communities that are conducive to plant development. Indigenous populations in the Amazon have utilized ADE for agricultural purposes for several centuries, eliminating the need for artificial fertilizers.
Key Research Insights
The study revealed that the microorganisms present in ADE, including bacteria, archaea, and fungi, are highly beneficial to plant growth. When ADE was added to soil, it notably accelerated the growth of the three examined tree species. For instance, saplings of Brazilian cedarwood and Yellow poinciana exhibited growth that was between two to five times their usual height in 20% ADE soil and between three to six times in 100% ADE soil, compared to control soil. Ambay pumpwood experienced no growth in control soil but thrived in soil fully enriched with ADE.
In a comparative analysis, Brachiaria forage grass displayed over threefold increase in dry mass when grown in soil containing 20% ADE and over eight times the increase in 100% ADE soil.
Anderson Santos de Freitas, the lead author of the paper, explained that the bacteria in ADE facilitate the conversion of certain soil molecules into forms that are more readily absorbable by plants. In other words, these bacteria function as microscopic “chefs” that make nutrients more bioavailable for plants.
Chemical analyses also indicated that ADE contains substantially more nutrients than control soil—30 times more phosphorus, and three to five times more of each other tested nutrient, except for manganese. ADE also exhibited a higher pH level.
Methodology Employed
To conduct the study, Zagatto and his team obtained ADE samples from the Caldeirão Experimental Field in the state of Amazonas. The control soil was sourced from experimental farmlands managed by the Luiz de Queiroz College of Agriculture in Piracicaba, São Paulo.
A total of 36 four-liter pots filled with 3 kg of soil each were placed in a greenhouse with an average temperature of 34°C, in anticipation of climate change effects. The pots were divided into three categories: control soil, a mix of control soil and ADE, and 100% ADE. Brachiaria forage grass was then planted in each pot and allowed to grow for 60 days before moving on to the next phase of the experiment, which involved planting seeds of the three selected tree species.
Biotechnological Applications
Zagatto clarified that their goal is not to advocate the exploitation of ADE as it is a limited and protected resource. The focus is on understanding the chemical, enzymatic, and biological properties of ADE that benefit plant growth. Future research aims to replicate these beneficial characteristics through biotechnological methods.
The study serves as an initial step towards more efficient restoration of deforested areas, which is of paramount importance for Brazil and other regions dealing with extensive deforestation. The utilization of ADE’s properties in tree seedling production or directly in affected regions could potentially hasten the ecological rehabilitation of tropical forests.
For further details on this research, refer to the article titled “Amazonian dark earths enhance the establishment of tree species in forest ecological restoration,” published on 5 May 2023 in Frontiers in Soil Science with DOI: 10.3389/fsoil.2023.1161627.
This research project was funded by FAPESP under its Biodiversity, Characterization, Conservation, Restoration and Sustainable Use Program (BIOTA), with support from projects 20/08927-0, 18/19000-4, and 14/50320-4.
Frequently Asked Questions (FAQs) about Amazon Dark Earth
What is the main focus of the Brazilian research on Amazon Dark Earth (ADE)?
The primary objective of the research is to understand the unique properties of Amazon Dark Earth (ADE) that contribute to accelerated tree growth. The study aims to leverage these characteristics for effective ecological restoration and considers possible biotechnological applications.
What significant impact does ADE have on tree growth?
Amazon Dark Earth (ADE) has been found to increase the rate of tree growth by up to six times compared to control soil. It also improves the overall health and quality of the trees.
How does ADE affect microbial communities?
ADE is rich in essential nutrients and supports a diverse range of microorganisms such as bacteria, archaea, and fungi. These microbial communities contribute positively to plant development by making soil nutrients more bioavailable.
What were the experimental conditions used in the study?
The researchers collected ADE samples from the Amazonas state and control soil from São Paulo state. They filled 36 pots with soil and placed them in a greenhouse with an average temperature of 34°C. Different proportions of ADE and control soil were used to observe the effects on plant growth.
What are the biotechnological implications of the study?
The study aims to understand the specific chemical, enzymatic, and biological properties of ADE that are beneficial for plant growth. This understanding could lead to the development of biotechnological methods to replicate these beneficial characteristics for ecological restoration.
Is the use of ADE for agriculture a new concept?
No, indigenous populations in the Amazon have utilized ADE for agricultural purposes for several centuries. It eliminates the need for artificial fertilizers due to its rich nutrient content.
How was the research funded?
The research was funded by FAPESP under its Biodiversity, Characterization, Conservation, Restoration and Sustainable Use Program (BIOTA). It was supported by specific project codes: 20/08927-0, 18/19000-4, and 14/50320-4.
What is the significance of this research in the context of deforestation?
Deforestation is a critical issue not only in Brazil but globally. The study serves as a foundational step towards finding efficient ways to restore deforested areas. The utilization of ADE’s properties could potentially speed up the ecological rehabilitation of tropical forests.
More about Amazon Dark Earth
- Frontiers in Soil Science Journal Article
- University of São Paulo’s Center for Nuclear Energy in Agriculture (CENA-USP)
- FAPESP Funding Programs
- Amazon Deforestation Statistics
- Introduction to Biotechnology and Soil Science
- Ecological Restoration Initiatives in Brazil
- Soil Microbiota and Plant Growth
- Global Warming and its Impact on Amazon
- Indigenous Agriculture Practices in the Amazon
