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  • From: "robscott@freeshell.org" <robscott@freeshell.org>
  • To: permaculture@lists.ibiblio.org
  • Subject: [permaculture] the double-digging issue
  • Date: Wed, 31 May 2006 00:33:21 +0000 (UTC)


I took the Grow Biointensive Introductory Course with John Jeavons this spring. Having become familiar with the hearsay about the double-digging method, I wanted to hear Jeavons make the case for it himself. I was impressed by the thoroughness of the research they've done out there in Willits, California, as well as other places such as Mexico and Kenya.

The Biointensive system is designed to meet human needs on the smallest piece of land with minimal or no inputs. That's why annual vegetables and double digging (on-site human labor) are emphasized. They grow crops for calories and carbon (for compost) and aim for self-reliance with minimal input.

The double-digging makes sense where there are old, deep, clay soils. In these areas, crop growth can be severely limited by lack of oxygen to the roots, and double digging ensures that any area can become productive right away by improving drainage.

Here in Illinois, there are more than 10 million acres with drainage pipes installed to create the same effect in America's agricultural heartland. Most of America's corn, soy, and wheat comes from fields with deep drainage, comparable to double dug beds. What Jeavons did is develop a small scale system for communities, and kept track of what worked and what didn't, so that people with limited land and clay soil could have a hope for self reliance in vegetables using simple tools, seed-saving, and compost. As he said to me: if you can get better results without double digging in your area, do a comparison and let's publish the data.

Areas with less than 10" of soils don't really count against this system, Mitch, because they don't have deep anaerobic soil dynamics. Rock isn't soil. The design principle, if you will, is getting oxygen to plant roots, not only water. In some areas this won't be a major issue. Sandy soils, for instance. The issue is oxygen. Double-digging is just one method.

Rob
Urbana, IL





  • [permaculture] the double-digging issue, robscott@freeshell.org, 05/30/2006

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