Secret of Terra Preta Soil Discovered?

We’ve discussed the basics of terra preta soil – the most fertile soil in the world – in two previous blog posts. As I explained in the earlier blog posts, scientists are racing to unlock the secrets of terra preta soil and the role that biochar plays. New biochar research is coming out that may hold the keys to restoring land degraded from years of industrial chemical farming. If the claims made in the following videos turn out to be true then that means we now know how to develop permanent soil fertility. In addition, you can heat your home and greenhouse from waste heat given off during the biochar making process. This BBC documentary — The Secret Of Eldorado – TERRA PRETA — explains why terra preta is more valuable than gold. Test trials have shown terra preta can produce 880% increase in plant yields.

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Building Garden Soil — Throw the Sink at It

Here’s a brief list of things we’re doing to boost the quality of our soil in our forest garden. I’m writing this because I saw a video a while back that explained why they don’t use worm castings, compost tea, leaf mulch, rock dust and so on any more. That video might confuse some people into thinking these things aren’t helpful. What actually happened is their soil has become so good (by using these materials!) in their small backyard garden raised beds that these soil amendments are no longer necessary. Since they’re only dealing with a few pickup loads of soil, it’s not overly difficult to create that much high quality soil.

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More Details about Terra Preta

Left - a nutrient-poor oxisol; right - an oxisol transformed into fertile terra preta using biochar.
Left – a nutrient-poor oxisol; right – an oxisol transformed into fertile terra preta using biochar.

I’m really fascinated with the terra preta/biochar concept. We briefly touched on the subject in our blog post Big Ideas that are Changing the World. Watch the excellent video there for a good overview of the subject.

Terra preta is nothing short of amazing. It’s considered the most fertile soil in the world, and has retained its fertility over thousands of years. Studies have reported positive effects from biochar on crop production in degraded and nutrient–poor soils. Biochar–enhanced soils can indefinitely sustain agricultural production [that means forever!], whereas non-amended soils quickly become depleted of nutrients. Compare terra preta to modern industrial agriculture that gradually depletes soil and pollutes groundwater and food sources with toxic chemicals.

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Adjusting the Clay/Aggregate Ratio of Road Base

All of our earthbag projects have been built using the same road base material. It has worked exceedingly well. After tamping, the earthbags are solid and turn into very hard earthen blocks. Here I am testing the hardness of bags on our roundhouse. But from time to time I would see areas with less than … Read more

Earthbag Building Blog 3rd Anniversary

This week is the 3rd anniversary of Earthbag Building Blog. A lot has happened this past year, and our blog continues to grow in content and readership. There are now 335 posts and well over 1,000 comments. Thanks for your support. We love hearing about your earthbag projects and hope you will continue sharing information … Read more