For
the last ten days I did some gardening in my daughter's garden in
Mountain View, CA. Also some hiking on the coast and redwoods. And
the striking result is some sort of jealousy on the good soil as
compared to the poor soil of Grabov Rat (the peninsula, not the
website, of course). Miser- able soil, that is more appropriate.
The
dominant type of mediterranean soil is terra rossa (Italian
for red soil), a type of red clay soil produced by the
weathering of limestone, along with non-soluble rocks. The residual
deposits are rich in iron hydroxides which give the red to orange
color. That's a general statement. What is terra rossa like in a
particular mediterranean area, that's another story. Thin soil and
high stone content on Grabov Rat make gardener's life unfortunate.
When I dig a foot deep hole for planting, the stone to soil ratio is
typically 3:1 !! Then I remove, by hand and sieve, most of the
stones larger than half inch and mix in an equal amount of humus
from my com- post site or commercial top soil (not of mediter-
ranean origin). The resulting mixture, which I don't dare to call
mediterranean soil, has stone to soil ratio close to 1:1.
If
you think that the term terra rossa is not scien- tific
enough, you are not alone. The UNESCO/FAO World map equivalent is
the chromic luvisols (a suborder of the luvisols), and
the USDA soil taxonomy equivalent is the rhodustalfs (a
suborder of the ustalfs). Scientists have to do something,
don't they? The classification could be a very consuming task, like
the 3:1 ratio.