Year for the Planet Week 31: Fertile Futures – Dark Earth and the Amazon

Before you can fix the world, you have to fix yourself. Year for a Planet is a personal challenge to be a better human for the planet for a whole year. This year, 2017, is where I deal with my food choices.


Here’s something interesting I learned in Brazil: in the Amazon Basin, there are places that have terra preta, or dark earth—manmade, nutrient-rich soil from early human settlements. It owes its black color to charcoal, and has traces of plants, animal bones, feces, and broken pottery. In this rich soil, scientists have found nutrients such as nitrogen, phosphorus, calcium, magnesium, and potassium. It was like the compost heap or garbage dump of indigenous ancestors. Aside from the Amazon, other places such as  Britain and Sweden also have it.

About four years ago, I did a project on soil where I collected samples of earth from all 43 mountains of Seoul, South Korea. Before, soil was never an interest of mine, and yet when I lined up all the jars together, I saw how different they were in terms of color, particle size, and even the little organisms that ended up in the collection process. Soil is marked with the traces of the life that it helped grow. In some samples, I would see traces of concrete, and I became suspicious that this “mountain soil” was actually “landscape soil” from a construction company.

But I digress. In the Amazon, soil is relatively infertile at least for growing crops, and so dark earth is supposed to be an agricultural improvement. What is striking, other than evidence of human settlement in the Amazon (estimates have ranged that dark earth covers 0.1-0.3%, or in other studies, 10% or more, of low-forested Amazonia), is that these humans actually improved the soil for future generations.

This is in stark contrast to the escalating soil crisis we have in the world, where we have stripped off our soils of a lot of their organic matter that allow us to grow food. Heavy machinery and livestock also contribute to soil compaction, preventing rainwater from sinking through the soil and increasing flooding in some areas. What’s more, wasteful consumption has given us a potential future of seeing plastic as a fossil of our time. The things we include in our soils now won’t give future generations dark earth, but useless plastic bricks. Our soils are turning into dirt.



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