We were talking about the ocean. Now let’s talk about the earth. More specifically, let’s focus on the soil , that which gives us the food that all of us need.
There is a truly terrific piece in the latest “National Geographic,” Our Good Earth. It looks at all manner of good news and bad news in how we use the earth. In the developed world, one way we degrade our food-producing soil, among a number of ways, is through compaction by great honking harvesters and other gargantuan machines. In the developing world, we cut down the forests and grasslands for cropland. This practice, of course has enormous implications for exacerbating global warming. See Are Biofuels A Bummer? But let’s stick here now to the impacts on agricultural productivity.
The NGM article says “In the first‚ and still the most comprehensive‚ study of global soil misuse, scientists at the International Soil Reference and Information Centre (ISRIC) in the Netherlands estimated in 1991 that humankind has degraded more than 7.5 million square miles of land. Our species, in other words, is rapidly trashing an area the size of the United States and Canada combined.” The article details some of the practices that have led to this massive degradation.
It also looks at some extraordinarily hopeful developments like the Keita Project in Niger sponsored by the Italian government, the use of cordons pierreux (long lines of fist-sized stones) to trap rainwater and silt, and the use of zaï , foot deep holes in the fields that are then salted with manure. Read this great article and also see NGM’s companion “geopedia” on soil for more information.
Perhaps the most fascinating focus in the article is on the terra preta do indio - the “black Indian earth” of the Amazon. Wim Sombroek, the Dutch soil scientist, went to Amazonia in the 1950s and found hugely fertile pockets of soil in oases amid the acidic, poor soils of the rainforest. Sombroek was something of a giant in his field, becoming director of ISRIC for a time and SG of the International Union of Soil Sciences (IUSS). He devoted much of his life to studying the terra preta and fostering a movement to adopt the same approach to soil enrichment.
What is terra preta? It’s the result of an ancient Amazonian practice of using charcoal and other carbon-rich inputs to build up the soil. This soil retains its richness for centuries and is stunningly productive. In an outstanding article from “Nature” in August of 2006, Black is the New Green, we learn all about the ins and outs of terra preta. “Everyone agrees that the explanation lies in large part with the char (or biochar) that gives the soil its darkness. This char is made when organic matter smoulders in an oxygen-poor environment, rather than burns. The particles of char produced this way are somehow able to gather up nutrients and water that might otherwise be washed down below the reach of roots. They become homes for populations of microorganisms that turn the soil into that spongy, fragrant, dark material that gardeners everywhere love to plunge their hands into.”
Sombroek saw so much potential in this that he created a movement for terra preta nova. Research into this area has exploded since his book in 1966 on Amazonian soils, and scientists and others have been gathering force to help promote this approach not only for the wholesale restoration of degraded soils all over the world, but to sequester massive amounts of carbon. In this Cornell University “Science Brief,” Terra Preta: Soil Improvement and Carbon Sequestration, we note that “Bio-char (biomass-derived black carbon) is highly stable in soil and can persist hundreds and thousands of years. It is much more stable than even the most stabilized carbon in soil. It therefore constitutes a much longer carbon sink than most other sequestration options such as no-tillage, manure applications, or afforestation.” Cornell scientist Johannes Lehmann is doing a lot of work in this field. For more, see his website.
Eprida, a “technology development company and social purpose enterprise,” is doing cutting-edge work in developing this sort of approach not only to sustainable agriculture but to renewable energy production and carbon sequestration. See their flash animation on the “Eprida cycle.” See also this “Scientific American” special report from last year.
This is but one more way for us to mimic nature’s way. As Stewart Brand noted in the Whole Earth Catalogue a good many years ago now, “We are as gods, and we might as well get good at it.” It has always seemed to me that the “godlike” approach to life is the simple one. As you will have noted at this blog, the low-tech, decentralized, KISS (keep it simple, stupid) approach wins my heart more often than not. (See my posts, for instance, on Habitat; Green Tech, Low Tech, Clean Tech, New Tech; and Black Carbon and Solar Cookers.) I am, after all, one of those old hippies still dreaming of Aquarius and all that happy jazz. But as no less a personage than Kevin Hydes, the chairman of the World Green Building Council, pointed out to me, the counterculture produced a tremendous amount of creative thinking that has borne fruit in many ways.
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