Sustainable Agriculture in a (Coco)nutshell

Guest post by Mike Graeme during Sustainable Indigenous Economies and Ecologies of Peru field school

At the Sachamama Centre for Biocultural Regeneration there is a chacra-huerto—a subsistence food forest garden.

It is a terraced, polycropped, rotational garden incorporating a millennia-old Indigenous soil-building technique locally called Yana Allpa, and more widely known as terra preta, or Amazonian Dark Earth (ADE). On our third day at the Centre we get our hands in this deliciously dark dirt!

Scientists have deemed this soil the most sustainable soil in the world, says Dr. Frédérique Apffel-Marglin, one of our professors and the founder of the Sachamama Centre for Biocultural Regeneration in the Peruvian High Amazon.

We pour bags of the dark Yana Allpa soil onto the garden beds before wetting them down and digging little holes for some thirsty lettuce plants.

One of the students, Caleigh Aalders, says the reason she enrolled in the field school in the first place was because finding out about the dark earth was a turning point in her outlook—a light of salvation in the darkness of the 21st century. She says, “Whenever anyone asks me, ‘Don’t you get depressed being in environmental studies and learning about all the world’s problems?’ I reply, ‘Well, there’s biochar!’”

Biochar is one of the central components of this time-honoured Indigenous soil technology. It is made from burning biomass at high temperatures without oxygen, creating a porous charcoal that serves as a magnet for nutrients.

As I dig homes for my lettuce plants, I get my first glimpse of one of these nutrient magnets. It’s a thin, rock-hard shard of charcoal. The biochar we cook here is made from coconut husks, Dr. Apffel-Marglin tells us. It’s the most widely available sustainable biomass around here.

Not only does biochar stick to nutrients like the juice of a fresh mango to a happy face, but it also constantly renews its ability to capture nutrients. When I was traveling in this same region a year and a half earlier, after another UVic study abroad, I had the book 1491: New Revelations of the Americas with me. I remember reading that the ability of this charcoal to oxidize over time allows a constant renewal of nutrient binding sites—it is continuously regenerating itself![1]

Indeed, when archaeologists recently began rediscovering the soil they found it to be still fertile 8,500 years after it was made, says Dr. Apffel-Marglin.

Makoto Ogawa, a Japanese scientist, estimated biochar can retain “its carbon in the soil for up to fifty thousand years.”[1]

With excessive carbon floating around in the atmosphere causing global climate change—arguably the biggest plight of our time—this soil technology is, as Caleigh Aalders said, a beacon of hope.

It’s sustainable agriculture in a nutshell—or a “coconut shell” to be more precise.

The cool thing with biochar, says Dr. Apffel-Marglin, is that not only does it offer a way of locking nutrients in the soil, but it also has a tremendous ability to sequester carbon. If all agriculture used this technique, carbon emissions would be neutralized, she says.

Deforestation of tropical forests for food growing is a key contributor to climate change. 52 trillion kilograms of carbon—equal to about a third of all industrial emissions the world over—are released every year due to the clearing and burning of tropical forests, often for food growing.[2] Burning vegetation (without a biochar oven, that is) also depletes soil fertility over the long run, as it releases much of the soil’s nutrients into the air.

But it hasn’t always been like this.

Indigenous people of the region ”practiced agriculture here for centuries,” soil scientist Bruno Glaser told Charles Mann, author of 1491, “But instead of destroying the soil, they improved it, and that is something we don’t know how to do today.”[1]

To be sure, this technology is in stark contrast with industrial agriculture technology, which exhausts soil fertility as quickly as I am exhausting my sweat glands being in this High Amazon heat. And to redress the problem—or rather to ensure food productivity and profit don’t plateau—industrial agriculture just ups the ante by pumping the soil with more chemical fertilizers, which pollute waterways and contribute to climate change.

We ask our professors when we will get to learn to make this miracle soil. Unfortunately, we are told that cooking biochar takes four hours and equally as long to cool, and our field school timetable is jam-packed already.

Nonetheless, we plead and plead like children at the Oro Verde fair trade chocolate store up the road and eventually we get our wish. You just gotta love field schools for their adaptive response to student interest. A few days later we are shovelling coconut husks into the Sachamama Centre’s biochar ovens.

We seal the husks in the oven and light a fire beneath it. Once the oven temperature reaches 400 degrees Celsius, a lever on the back of the oven is pulled. This allows the “syn gas,” which has built up in the oven, to be released through a pipe cycling back into the fire beneath where it combusts and neutralizes, so as not to become a greenhouse gas itself.

Once the husks are cooked and taken out of the oven, we quickly pour water on them to make sure they don’t keep burning, which would result in the charcoal turning to ash and losing its nutrient magnetism. We then leave the biochar to cool before mixing it with other ingredients the following day.

Beyond biochar, we learn that another important ingredient of the Yana Allpa soil is the addition of microorganisms fermented to a precise pH (3.5-4). When scientists first started studying this soil, they found it contained “as much as a hundred times more bacteria than adjacent soils, and that these bacteria were almost completely different from those nearby. Many species were apparently new to science.”[1]

So this soil is literally alive! But not only because of its microorganism content. As I wrote about in a recent blog post, the soil and earth are alive with spirits. The spirit of Mama Allpa is honoured by offering ceramic shards, which is another important ingredient found in Yana Allpa.

When envisioning a livable future on this earth, it helps to consider the basic nature of our connection to our food and the soil.

“At either end of any food chain,” writes Michael Pollan, author of The Omnivore’s Dilemma, “you find a biological system—a patch of soil, a human body—and the health of one is connected—literally—to the health of the other.”[3]

Carefully creating a healthy soil that would feed our baby lettuce plants, as we did on the field school, was a process that was foreign to me. I often lack the chance to get my hands in the soil, to reach into the other end of the food chain.

The industrial food system from which many of us get our food obscures our relationship with the soil. I already knew this, but something else has dawned on me. The industrial food system is itself isolated from the soil. It doesn’t understand it. It only looks for the next chemical fix to try to jumpstart it into productivity.

The food systems out of which biochar and the sustainable Yana Allpa dark earth were born, on the other hand, are based in reciprocity and respect, and serve to continuously regenerate rather than rapidly deplete mother earth’s bounty.

On the last day of the field school, I return to the chacra-huerto and find that our lettuce plants have already grown big over the last two weeks. I marvel at them, and I marvel these Indigenous relationships with the soil that we have been fortunate to start to comprehend.

I sniff the air. The neighbour is burning vegetation again. While I’m saddened to think about all the problems across the world resulting from unhealthy relationships with the soil, I realize that along with our little lettuces, a coconut of hope has been growing in my heart.

“Well,” I think aloud to myself, recalling Caleigh’s uplifting comeback, “there’s biochar!”

[1] Mann, C. C. (2012). 1491: New Revelations of the Americas Before Columbus. New York: Knopf.

[2] Davis, W. (2002). The Clouded Leopard: Travels to Landscapes of Spirit and Desire. Toronto: CNIB.

[3] Pollan, M. (2016). The Omnivore’s Dilemma: A Natural History of Four Meals. New York, NY: Penguin Books.