[permaculture] arid soil building
raincascadia at yahoo.com
Tue Dec 15 14:46:59 EST 2009
I agree with Dieter on the folly of generalizing too much about Mediterranean climates (or practically anything else). As far as fertility goes, arid climates can have very fertile soils because their minerals don't get leached out as much. Coastal California and Australia generally have infertile soils because they are so old, and have been leached for millions of years. Chile, interior California, and the Mediterranean have a lot of recent volcanic activity (at least in some areas), and therefore have more fertile soils. I don't know much about South Africa.
One thing that has barely been touched upon is how nutrient cycling varies from more humid temperate climates. In the Summer, nitrogen from animal manures, mulches, and compost just returns to the air if there is not sufficient irrigation. This means that we need to think differently about how to manage these things in Mediterranean climates.
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