So… compost? The article seems to be simply describing the process of composting, but with non-standard terms to make it sound more mysterious and “exotic”. Like, I could describe my local...
So… compost? The article seems to be simply describing the process of composting, but with non-standard terms to make it sound more mysterious and “exotic”.
Like, I could describe my local composting situation as “To make this mysterious terra preta, the native carefully adds husks of maize and allium to a hollow drum stood on its side, along with tough fibrous board made from a dried wood pulp. He returns to the drum in a daily tending ritual, rotating it to mix the contents. Through wisdom passed down in his community, he also knows to incorporate a special type of segmented worm found in the soil to accelerate the decomposition process.”
And the description wouldn’t be inaccurate, but it would certainly contain a lot of interesting phrasing choices.
Or I could just say “He tosses food scraps and cardboard in a compost bin and turns it over every day or so. When he finds worms around the yard, he tosses those in too.”
The big difference is the intentional addition of charcoal and ashes. Ashes return concentrated minerals (phosphorus, potassium, iron, calcium, etc.) to the soil, while neutralizing acidic...
The big difference is the intentional addition of charcoal and ashes. Ashes return concentrated minerals (phosphorus, potassium, iron, calcium, etc.) to the soil, while neutralizing acidic products of decaying plant matter.
The biochar addition is more complicated. It's not certain how much of the carbon content in terra preta is the residue of slash-and-burn practices (which deplete soil biota for a period of time), and how much is intentional addition of household charcoal from wood-burning to composted materials.
Modern research on biochar suggests that it improves soil porosity; increases surface area for moisture retention, microbial and mycelial growth; improves nutrient and mineral retention; and reduces soil acidity, in addition to sequestering carbon. Biochar-enhanced soils are more fertile than composted alone.
[The slow version of this is hugelkultur, where unburned, intact branches and logs are buried. But it's more labor-intensive and better suited for non-migratory societies with permanent property ownership.]
Rodrigo Pérez Ortega (tap/click to know more...) Terra preta To get to the bottom of its origin To fertilize the ground and create dark earth, or eegepe Lore “We already know what black earth is,...
Rodrigo Pérez Ortega
Soil study suggests today’s Indigenous Amazonians are making new terra preta
Mysterious patches of fertile black soil pepper the verdant Amazon rainforest. They sit in stark contrast with the reddish, eroded soil that dominates the basin. Researchers have long thought this Amazonian dark earth—or terra preta—was created by pre-Hispanic Indigenous civilizations, which have inhabited the region for millennia, but it wasn’t clear how. Now, a multidisciplinary team of scientists and Indigenous partners suggests the ancient Amazonians intentionally created the rich soil thousands of years ago to better foster their crops, and that their modern-day descendants are still making new terra preta today.
(tap/click to know more...)
The Amazon’s terra preta is much darker—black or dark brown—more fertile, and holds much more organic carbon than most of the region’s soils. Crops grow better in it because of its high phosphorus, nitrogen, and calcium content. And because of its supercharged carbon content, scientists consider it an important carbon reservoir that sequesters greenhouse gases.
Terra preta
Terra preta (which literally means "black soil" in Portuguese) is a type of very dark, fertile anthropogenic soil (anthrosol) found in the Amazon Basin. It is usually found near archaeological sites and contains charcoal, organic matter from food remains—such as fish and animal bones—and ancient artifacts such as pottery shards, hinting that ancient civilizations contributed to its formation. But Western researchers have debated whether they made it so on purpose or it occurred serendipitously from their practices. Some researchers, including Silva, have even suggested that nutrients were deposited naturally in dark earth thousands of years before human intervention.
To get to the bottom of its origin
Morgan Schmidt, an archaeologist and geographer at the Federal University of Santa Catarina, and his team focused on the soil of the Kuikuro Indigenous Territory, on the upper Xingu River in the southeastern Amazon of Brazil. There, scientists analyzed soil from four archaeological sites as well as two historic villages occupied from 1973 to 1983 and one modern village, Kuikuro II. Radiocarbon dates suggested the oldest sample is 5000 years old; most ranged from 300 to 1000 years old.
To fertilize the ground and create dark earth, or eegepe
To figure how the Kuikuro make this modern terra preta, Schmidt—who has been working in the region for more than 20 years—teamed up with Kuikuro villagers including co-author Taku Wate Kuikuro. Schmidt and the Kuikuro noted that residents gather fish and cassava waste in trash heaps that grow up to 60 centimeters high. The nutrients from the decaying matter slowly seep down into the soil. After a few years, residents use this soil to plant crops that wouldn’t thrive in unmodified soil. The team also documented how Kuikuro farmers purposefully spread organic ash and charcoal, as well as cassava waste, in fields—which they call ilũbepe (literally “what was ashes”)—to fertilize the ground and create dark earth, or eegepe, for later cultivation.
Lore
“Charcoal and ash we sweep, gather it up, and then throw it where we will plant, to turn into beautiful eegepe, there we can plant sweet potatoes,” Kanu Kuikuro, an elder and farmer, told the team in interviews. “When you plant where there is no eegepe, the soil is weak. That is why we throw the ash, [cassava] peelings, and … pulp.” Whereas most of the villagers the scientists interviewed agreed that their actions directly contributed to the creation of terra preta, a few gave different accounts, suggesting Tãugi, the Sun god, created dark earth, of that it was their ancestors who made it, not them.
“We already know what black earth is, but we didn’t know how it worked,”
The new results are important for Indigenous people in the region, says Taku Wate Kuikuro, who helped interview residents and excavate archaeological sites. “We already know what black earth is, but we didn’t know how it worked,” he says. Now, “We know what actually happens with the land … how old it is, and why it’s good for cultivating.” Other villages, he says, now want to also partake in the research. “We’re happy. All Xingu people are happy.”
“That’s something new as well that nobody’s ever really shown before. … [And] the most likely explanation is that they were doing the same things in the past.”
Evidence abounds that dark earth is tied to the ancient Indigenous groups living in the Amazon for thousands of years, Schmidt says, but this is the first time scientists have documented the making of dark earth in modern times.
Skepticism
Silva applauds the ethnographic part of the new study. “This is really novel,” he says. “I’ve never seen anything like this done for the origin of [dark earth].” Still, he says there’s not enough evidence to prove that ancient Indigenous groups were also creating dark earth in the same way. “That is a big claim.” He’s not convinced the process is as fast and simple as the new study suggests. “I don’t think we’re there yet.”
So… compost? The article seems to be simply describing the process of composting, but with non-standard terms to make it sound more mysterious and “exotic”.
Like, I could describe my local composting situation as “To make this mysterious terra preta, the native carefully adds husks of maize and allium to a hollow drum stood on its side, along with tough fibrous board made from a dried wood pulp. He returns to the drum in a daily tending ritual, rotating it to mix the contents. Through wisdom passed down in his community, he also knows to incorporate a special type of segmented worm found in the soil to accelerate the decomposition process.”
And the description wouldn’t be inaccurate, but it would certainly contain a lot of interesting phrasing choices.
Or I could just say “He tosses food scraps and cardboard in a compost bin and turns it over every day or so. When he finds worms around the yard, he tosses those in too.”
The big difference is the intentional addition of charcoal and ashes. Ashes return concentrated minerals (phosphorus, potassium, iron, calcium, etc.) to the soil, while neutralizing acidic products of decaying plant matter.
The biochar addition is more complicated. It's not certain how much of the carbon content in terra preta is the residue of slash-and-burn practices (which deplete soil biota for a period of time), and how much is intentional addition of household charcoal from wood-burning to composted materials.
Modern research on biochar suggests that it improves soil porosity; increases surface area for moisture retention, microbial and mycelial growth; improves nutrient and mineral retention; and reduces soil acidity, in addition to sequestering carbon. Biochar-enhanced soils are more fertile than composted alone.
[The slow version of this is hugelkultur, where unburned, intact branches and logs are buried. But it's more labor-intensive and better suited for non-migratory societies with permanent property ownership.]
Rodrigo Pérez Ortega
(tap/click to know more...)
Ref. Morgan J. Schmidt et al., Intentional creation of carbon-rich dark earth soils in the Amazon. Sci. Adv. 9, eadh8499(2023).