[permaculture] arid soil building

Doug Clapp doug.s.clapp at gmail.com
Fri Dec 4 10:14:10 EST 2009


One of the best comments I've read about "soil building" is from Joel
Salatin's "You can Farm!" where he says:

"Soil doesn't deepen, it uppens."

On Fri, Dec 4, 2009 at 5:37 AM, Dieter Brand <diebrand at yahoo.com> wrote:

> Rain,
>
> I live in a severely dry type of Mediterranean climate with between 12 to
> 25 inches of rain per annum usually between October and April.  However,
> this year we didn’t get any real rain from February to November, and with
> temperatures in the 80 to 90 F range from March through October, the soil
> has been dry for about 9 months.  We have a badly eroded hillside property
> with heavy clay and hardly any top soil.  In some places there is not more
> than a foot of clay and rubble on top of the solid rock.
>
> Traditional farmers here, like in most arid regions of the World, use
> tilling and manure for Dryland Faming with a Dirt Mulch.  The dirt mulch is
> extremely efficient in cutting soil evaporation to zero.  If it does rain or
> if irrigation is used, the soil needs to be hoed immediately afterwards to
> prevent soil humidity evaporating through the capillaries forming in the
> soil crust.  Irrigation is performed by flooding channels between the rows.
> Plants are widely spaced.  With zero evaporation, no transpiration through
> weeds and wide spacing it is possible to grow crops from May to August with
> _zero rain_ because all remaining soil humidity can go to the food crops.
> Wheat is grown from November to June.  This season, farmers will loose the
> cool season crop, because it only started to rain in December, which is too
> late for sowing so as to get a harvest before the next dry season.
>
> This type of _bare-soil cultivation_ has permitted generations of farmers
> to make a living under very difficult circumstances.  On the downside, it is
> extremely hard labor to hoe a field in the scorching sun from morning till
> night.  There are a few old farmers who continue the tradition even today,
> but for young people who leave the land for the city it is far too hard.
> The constant soil disturbance due to tilling and hoeing which is often
> performed during high temperature is also very bad for the soil.  As long as
> the soil was fed with manure, soil organic matter and fertility were
> maintained, but with the increasing use of synthetic fertilizers, the soil
> is bound to suffer even more.
>
> I have therefore experimented with _covered-soil cultivation_ typical of
> Natural Farming from rain-rich Japan.  My experience is that an _organic
> mulch_ can never be as efficient as a _dirt mulch_ in preserving soil
> humidity.  After years of tests I found that, in my unimproved clay soil,
> dry land crops like beans etc. will at most survive for 2 months under an
> organic mulch without water (no rain, no irrigation).  In a soil that has
> been improved by compost, mulch and cover cropping for 5 to 10 years, the
> same crop may survive for 3 or more months and even produce a meager
> harvest, but it is hardly worth the labor.
>
> When irrigation is used with a covered soil, much water is lost because it
> evaporates in the soil surface or the mulch layer.  Once the soil is dry,
> most irrigation water will run off the surface, vole tunnels or ant hills,
> without penetrating the soil.  Here again, the flooding used in traditional
> farming is a lot more effective since no water is lost; it all goes directly
> to the plant roots in the subsoil.
>
> After about 10 years of soil building in which I put a new humus-rich layer
> of topsoil onto the clay, I can grow most of our food without plowing,
> without fertilizers or any external input whatsoever, simply by returning
> organic matter to the soil.  But if I wanted to make a living by farming, I
> would have to use manure and tilling as in traditional farming.
>
> I think organic matter ought to be returned to the soil as _a living
> substance_ to feed the soil organisms and not as _a biologically dead_
> charcoal substance.  Biochar advocates claim that it improves water
> retention.  This may sometime be the case for sandy soil, I have no opinion
> on that.  But I believe charcoal may even reduce water retention in clay
> soil or make it water repellent when it dries out completely as it does in
> the dry season.  I have made very good experiences with organic matter in
> different forms (mulch, compost, humanure and even entire wood logs).  It is
> the best way of improving depleted heavy clay.  I do sprinkle the ashes from
> our wood stove on the fields, but I would never add charcoal.  Nor would I
> add lime, rock dust or a million other soil amendments offered by the
> shopping malls of alternative farming.
>
> Dieter Brand
> Portugal
>
>
> --- On Thu, 12/3/09, Rain Tenaqiya <raincascadia at yahoo.com> wrote:
>
>
> From: Rain Tenaqiya <raincascadia at yahoo.com>
> Subject: [permaculture] arid soil building
> To: permaculture at lists.ibiblio.org
> Date: Thursday, December 3, 2009, 9:21 PM
>
>
> We live in a classic Mediterranean climate, with about 35 inches of rain
> that comes in intense bursts that usually start from the middle of October
> and start petering out in April.  I feel there must be a lot of knowledge
> about this climate given its long history in Europe.
>
> I have started to compost in pits because it takes so long above ground.  I
> have even used tarps, as was recommended.  They help, but I really need to
> irrigate the piles to see reasonable results.  We have all sorts of fungi
> from the forest nearby, so I don't think inoculants are necessary.
>
> Part of my problem could be that aside from the first year, when we had
> record floods, we have been in a drought.  Maybe this is the new normal,
> however.
>
> We collect and use all of our humunure and urine, and I bring in a ton of
> leaves and straw from around our site.  I also have several long-term wood
> compost piles.  I finally broke down and got some rock dust, zinc sulfate,
> and gypsum, for specific areas.  I've also brought in forest soil from
> nearby for the main food forest and kitchen garden, which also got a layer
> of horse manure from a neighbor.  I'm thinking about spraying seeweed on
> trees that are doing the worse.  In general, however, I really want to
> minimize off-site inputs.
>
> As far as biochar goes, the soil actually has a fair amount of charcoal
> from past fires.  I couldn't justify putting all that carbon in the air by
> burning all the wood around our site.  If I wait long enough, a wildfire
> might do it for me, however.  Hmm, interesting.
>
> Rain
>
>
>
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