[permaculture] arid soil building
wade at coac.es
Sun Dec 13 10:53:40 EST 2009
Well, I've been ache'n to get in this discussion for some time so:
I live at 700mt. altitude in the coastal mountains of eastern Spain,
about 20 Km. from the sea. Mostly clay over limestone, but with some
lime soils. Average rainfall 400mm a year. one year in three we get half
that in one day! Then we can go four years in a row without summing up
that much! We have two small springs which provide water for the house
and enough for an intensive garden. All our crops are dryland.
I'd kind of like to start with a bit of history.
lbsaltzman at aol.com wrote:
> We live in a more Southern Mediterranean climate and have even less rain, though the pattern is similar. We are working a much smaller property than you have, and it has taken years to build up the soil. It is deep clay subsoil. The top soil had been depleted by bad orchard management back in the 1930s and 40s before the area had been sub-divided.
That is the story of Med Climates. They are fragil and easily abused.
But if you think you have it bad, my soils have been cultivated for at
least 1000 years! Luckely it has been terraced for the last 6 to 8
hundred years which did have the effect of slowing down the erosion. But
like most of the mediteranean area, it has been clean cultivated for at
least that long.
> We still have patches that are only suitable for perennials. Annuals just don't thrive in the heavy clay.
I think that you have the key here. Classic Med crops /are/ tree crops;
almonds, vines, olives, pistachos. The annual crops are practically all
winter growing, (fall seeded) crops like lentils, garbanzos, barley,
fava beans, etc. (There you have it! a Mediteranean diet!) Most soils in
southen europe were forests, (way back when) and that is probably true
for Dieter's place as well. And I don't have to tell you about the value
of trees. But most tree crops here are also clean cultivated, which
means you can find rampant erosion even in tree crops.
So getting back to dirt mulch, I can just about imagine that once the
trees were removed, the good soil couldn't last too long. Hot summers
and clean tillage would guarantee that. Failure to maintain the humic
soil of the forests let to dust (or dirt) mulching the kind Dieter
described and that is also practiced here as a way of conserving the
water. With high humus content, it's the humus that keeps the water in,
but you can't keep the humus and clean till at the same time. It's kind
of like a cat chasing it's tail. So years ago the humus was literally
"tilled" out of the soil.
We have been practicing what I call regenerative farming. About twenty
years ago when planting vines, the soil test read 0.06 organic material.
The rest clay and a pH of 7.9. Once the vines were up we let the weeds
grow all winter, and cut them back in March, leaving the weeds as mulch.
As long as the spring rains lasted we let the weeds grow back and then
cut them when the soil started getting dry. In a nutshell we managed our
weeds according to the moisture, when the transpiration got heavy we
cut, if it rained again we let it go. Usually by May we did the last
cutting. It was important for us to get at least one good seed set
before the first cutting, but sometime in drought years, (we've had up
to 4 years continuous) that can't be done. But then weeds don't grow
much then anyway.
Over time we've got a great variety of weeds with chichory, mustard,
fennel, as well as sweet clover, medicago lupulina, and of couse the
full run of annual gramineas and a variety of annual legumes as well. In
winter it is lush and green, in summer it is dry except for the tougher
legumes and gramineas.
In these twenty years the soil has gone from dark red to deep browish
black, with no puddling. On three ocasions i have roterey tilled to 7cm
when gramineas began to dominate too much. That is enough to get a flush
of new legumes and annuals.
In spite of all the warnings from my neighbors that my weeds were eating
up my vines, both production and quality have continually improved, and
in the worst droughts the organoleptic features of my wine was superior
to that of the rest of the village. That is a result of superior water
My olives and almonds are treated in the same way and with the same
So I have a kind of mantra that I repeat while working with my trees;
/manage your soil cover/. Med climates don't lack water, they lack
fertility!! And any strategy that increases fertility will increase water.
Well I hope some of this is useful.
> I swear that there should be an association of Mediterranean climate farmers and gardeners. We are a forgotten minority. I find few books that address our needs in general gardening or farming books. So much more is geared to temperate zone climates.
> -----Original Message-----
> From: Rain Tenaqiya <raincascadia at yahoo.com>
> To: permaculture at lists.ibiblio.org
> Sent: Thu, Dec 3, 2009 1:21 pm
> Subject: [permaculture] arid soil building
> We live in a classic Mediterranean climate, with about 35 inches of rain that
> omes in intense bursts that usually start from the middle of October and start
> etering out in April. I feel there must be a lot of knowledge about this
> limate given its long history in Europe.
> have started to compost in pits because it takes so long above ground. I have
> ven used tarps, as was recommended. They help, but I really need to irrigate
> he piles to see reasonable results. We have all sorts of fungi from the forest
> earby, so I don't think inoculants are necessary.
> art of my problem could be that aside from the first year, when we had record
> loods, we have been in a drought. Maybe this is the new normal, however.
> e collect and use all of our humunure and urine, and I bring in a ton of leaves
> nd straw from around our site. I also have several long-term wood compost
> iles. I finally broke down and got some rock dust, zinc sulfate, and gypsum,
> or specific areas. I've also brought in forest soil from nearby for the main
> ood forest and kitchen garden, which also got a layer of horse manure from a
> eighbor. I'm thinking about spraying seeweed on trees that are doing the
> orse. In general, however, I really want to minimize off-site inputs.
> s far as biochar goes, the soil actually has a fair amount of charcoal from
> ast fires. I couldn't justify putting all that carbon in the air by burning
> ll the wood around our site. If I wait long enough, a wildfire might do it for
> e, however. Hmm, interesting.
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