The Amazon, called the “lungs of the earth” because of its dense forests that produce oxygen, can absorb oxygen. 132 billion tons of Earth’s carbon.But over his 30,000 square miles of Amazon Lost From the 1970s. Deforestation, clearing of agricultural land, and wildfires caused by climate change have wreaked havoc on an area where about 10,000 acres of forest (roughly the size of California) have been destroyed every day since 1988.
But there is still time to save it. And now scientists may have a “secret weapon” that can help not only reforestation in the Amazon, but other depleted forests around the world. comes from the soil.
[Related: Brazil’s presidential election is a win for the Amazon—and the planet.]
From about 450 BC to 950 AD, generations of people living along today’s Amazonia transformed the originally poor soil. The soil was enriched with charcoal from low heat for burning cooking and waste, animal bones, broken pottery, compost, and manure. Amazon Dark Earth (ADE), or terra pretaThe highly fertile black soil is rich in charcoal-derived nutrients and stable organic matter.according to A study published May 5 in the journal Frontier of soil science, Now it could help reforestation the same areas where it was created.
“Here we show that the use of ADE can enhance pasture and tree growth, not only due to the presence of beneficial bacteria and archaea in the soil microbial community, but also due to high levels of nutrients. ‘ said co-author Luís Felipe Zagatto.Graduate Student, Agricultural Nuclear Energy Center, University of São Paulo, Brazil said in a statement“This means that knowledge of the ‘ingredients’ that make ADE so fertile could help speed up ecological restoration projects.”
The team’s primary objective was to study how soils containing ADEs, or ultimately microbiomes engineered to mimic ADEs, could promote reforestation. To do this, they conducted controlled laboratory experiments to mimic the ecological changes that occur in the soil when pastures in deforested areas actively revert to a forest state.
They sampled ADE from the Caldeirão Experimental Research Station in Amazonas, Brazil. The experimental control soil was from the Luis de Queiroz Agricultural High School in São Paulo State. They placed about 6.6 pounds of soil in a greenhouse with an average temperature of 94 degrees Fahrenheit. predict global warming It’s above the current average temperature in Amazonia (71-82ºF).
One-third of the pots received control soil only, another third received a 4:1 mixture of control soil and ADE, and the final third received 100% ADE. They planted seeds of fence grass, a common fodder for livestock in Brazil, to mimic a pasture. I was allowed to.
Each of the three soils was then replanted with seed from a colonizing tree called Ambay Pumpwood, Perforum dubium, or Cedro Blanco.
[Related: The Amazon is on the brink of a climate change tipping point.]
After allowing the seeds to germinate and grow for 90 days, the team measured seed height, dry weight and root elongation. , and organic matter (potassium, calcium, magnesium, aluminum, sulfur, boron, copper, iron, and zinc).
Initially, ADE showed higher amounts of nutrients than control soils, about 30 times more phosphorus and 3-5 times more of each of the other measured nutrients except manganese. ADE also had a higher pH and contained more sand and silt, but less clay.
After the experiment, the control soil contained less nutrients than at the start, reflecting uptake by plants. However, soils with 100% ADE remained richer than control soils, while soils with 20% ADE had intermediate nutrient levels.
20% and 100% ADE soils supported both bacterial and archaeal biodiversity more than control soils.
“Microbes convert chemical soil particles into nutrients that plants can absorb. Our data show that ADE contains microbes that are excellent at this soil transformation, and thus improve plant development. It will give us more resources,” says co-author Anderson Santos de Freitas, a molecular biologist at the University of São Paulo. said in a statement“For example, ADE soils contained taxa from more beneficial bacterial families. Paenibacidae, Planococcus, Micromonosporaceae, Hyphomicrobraceae”
Furthermore, adding ADE to the soil improved plant growth and development. The fence grass dry mass increased 3.4-fold in the 20% ADE soil and 8.1-fold in the 100% ADE soil compared to the control soil.
These results were enough to convince the team that ADE can promote plant growth, but caution is warranted.
“ADE takes thousands of years to accumulate, and with use it will take the same amount of time to regenerate in nature,” said co-author Siu Mui Tsai, a molecular biologist at the University of São Paulo. . said in a statement“Our recommendation is not to utilize ADE per se, but to copy its properties, especially its microbes, for use in future ecological restoration projects.”