Hundreds, if not thousands, of years ago, a very special soil was growing in the Amazon River Basin. Utilized by the native populations to improve crop yields, its origins are not fully understood. This soil, called “Terra Preta” (Black Earth) in Portuguese, is still around today and holds the same amazing benefits after all this time. Through years of study, experts have surmised that the ancient Indians knew of the value of this resource and utilized it, but can’t agree if they were deliberately made for farming or simply a by-product of habitation that was then taken advantage of.
The patches of Terra Preta found in the Amazon are varied, but the most important similarity is that all Terra Preta patches contain a much greater concentration of carbon (up to 15% compared to the 2-3% in surrounding areas) as well as other materials like pottery and bone. While the question of how this carbon got in to those specific patches of earth may never be answered, studies have shown how it affects cultivation. While some of the carbon is usually pulverized down to dust, there are still significant chunks that can be found while digging, which speaks to the longevity of carbon as a soil amendment. In addition to its longevity, the carbon is micro-porous, meaning it has a very high surface area to house microbes like bacteria and fungi, as well as to absorb nutrients. With nutrients absorbed and microbial life present, the carbon provides a great boost for plants growing above, which results in larger yields, increased water retention, and shortened (or even no) fallow time between crop cycles.
This carbon ingredient of Terra Preta has gained popularity recently under the name “Biochar” in modern gardening. Boosted by its results as a soil amendment, Biochar has largely been seen as a perfect use of the biowaste created in farming and agricultural development. When made as cleanly as possible and then sequestered, the carbon in Biochar aids plant growth above ground and even increases the ability for plants to take in carbon dioxide from the atmosphere.
Terra Preta’s evidence of carbon after thousands of years of development and use showcases its (and Biochar’s) ability to sequester carbon safely for centuries to come, and as a history buff, I personally find it fitting that one of the answers to helping secure our climate in the future has been sitting in the Amazon ground for almost 2600 years!
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Featured image from: ultrakulture.com
Bryochar 