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Subject: Healthy soil and sustainable growing

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  • From: "TradingPostPaul" <tradingpost@riseup.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: Re: [Livingontheland] improving soil moisture-retention
  • Date: Sun, 11 Feb 2007 12:45:38 -0700


Dieter, here are some items that corroborate your moisture-conserving
methods and practice of leaving biomass on top instead of turning it under.
I note esp Ken Hargesheimer's point about not turning under green manure
crops, in Countryside Magazine.

paul tradingpost@lobo.net
-------------------------------------


-- "To minimize the impact of drought, soil needs to capture the rainwater
that falls on it, store as much of that water as possible for future plant
use, and allow for plant roots to penetrate and proliferate. These
conditions can be achieved through management of organic matter, which can
increase water storage by 16,000 gallons per acre foot for each 1% organic
matter. Organic matter also increases the soil's ability to take in water
during rainfall events, assuring that more water will be stored. Ground
cover also increases the water infiltration rate while lowering soil water
evaporation. When all these factors are taken together the severity of
drought and the need for irrigation are greatly reduced."
http://www.attra.org/attra-pub/summaries/drought.html

"Valdemar de Freitas, EPAGRI's manager, showed us that the secret to
achieving zero tillage is applying massive amounts of organic matter to the
soil. Brazilian farmers, after some four years of applying gm/cc's to the
soil, are able to quit plowing. (This is now outdated as corroborated
recently by Valdemar. "We now know that plowing down green manure is a
much, much slower way to improving soil structure than going straight to
zero tillage. The enhanced biological activity under ZT is the key to soil
structure renovation." August, 2001) The advantages, in terms of better
soil structure, reduced soil compaction, higher fertility, and decreased
cost, are impressive. Interestingly, farmers often use non-leguminous
gm/cc's to increase biomass in order to quit plowing sooner. That is, they
spend scarce income on nitrogen fertilizer for three or four years in order
to achieve zero tillage sooner. The Brazilians' discovery explains why the
zero tillage gm/cc systems of northern Honduras-and Fukuoka's-produce so
well, while many traditional zero tillage systems do not. Thus we added a
third principle: use zero tillage."
- Ken Hargescheimer, in No-till, Permanent Bed Farming
http://www.countrysidemag.com/issues/4_2002.htm

Biointensive techniques can make possible a 200-500% increase in caloric
production per unit of area, a major increase in soil fertility while
productivity increases and resource use decreases, a 50+% reduction in the
amount of purchased organic fertilizer, a 99% reduction in the amount of
energy and a 67-88% reduction in the amount of water required per unit of
production, and a 100+% increase in income per unit of area.
http://biointensiveforrussia.igc.org/docs/695companion.pdf

Mulching controls weed growth, retains water in the soil, adds nutrients as
the mulch decomposes, and creates soil layers that are mixed by the
movement of soil dwelling organisms.
http://www.certifiedorganic.bc.ca/rcbtoa/training/soil-article2.htm .


*********** REPLY SEPARATOR ***********

On 2/11/2007 at 3:45 AM Dieter Brand wrote:

>Bobby,
> I have clay soil, hence I don’t know to what extend my experience can
be
>applied to your situation. In the South of Portugal, were I live, we have
>extreme arid conditions during the summer months, meaning, not a single
>drop of rain from May through September with temperatures of around 100 F
>in the July/August period.
> By improving my garden soil and using mulch, I was able to reduce
>irrigation by about 80% in 5 years. Last year, I used on average 1/2 litre
>for 1 m2 per day, which I was able to take from the surface water
>resources available on my property without pumping up any groundwater. On
>one field which hasn’t been ploughed for the last 12 years, I detected
>humidity near the surface even after two months without rain and without
>any irrigation at all. The field was still green after my neighbour’s
>field (ploughed every year) had gone dry for a long time. Even without
>humidity many plants can survive if the soil is crumbly and if there is
>plenty of organic matter.
> With sandy soil too, the most important thing is to increase organic
>matter. It is best to leave it at the top without turning it under. When
>turning under green manure, due to erosion and oxidation, more soil and
>nutrients may be lost than gained. Select the plants (cover crops, weeds,
>perennials, etc.) that will grow best under local conditions without
>irrigation. Cut them, shredding coarsely when necessary, and leave the
>residues as mulch on the surface. If you cover a green mulch with a mulch
>of shredded branches etc. you can protect the greens especially during dry
>conditions, and by the time the woody mulch starts to decompose you have
>already covered it by another layer the following season (Gilles Lemieux
>in Canada did some research on using shredded branches). After some time,
>an organic layer will form at the surface protecting and enriching even
>sandy soil.
> Regarding irrigation systems, after 10 years of experimenting with
>sprinklers, mini-sprinklers, drip systems, etc., I have come to the
>conclusion that “no-irrigation” is the best form of irrigation. I’m
not
>quite there yet, but I keep on trying. In the meantime, I simply use the
>open end of the garden hose, using my thumb to modulate the water jet into
>a smooth film which lands softly on layers of mulch. Watering different
>plots in turn once or twice a week, this doesn’t take more than half an
>hour every day for a 1000 m2 veg garden. Setting up and maintaining
>automated sprinkler systems takes a lot of time and invariably involves
>loss of water even with drip lines. Manually, you can give each part of
>your garden just the right amount of water.
> Other strategies for saving water are: growing as much as possible
>during the wet season and selecting plants (beans, etc.) that will grow on
>little or no water for the dry season. In my case, the crops I can grow
>during the winter include: most cover crops and small grains, almost all
>root vegetables, cabbages and winter-salads, fava beans, green peas, etc.
> I started to clear some of our land. About 30 acres completely overgrown
>after decades of neglect. One method that proved to be very successful is
>to throw the seeds (small grains, cover crops, etc.) right into the
>shrubs. Subsequent cutting/shredding (in one operation) of the shrubs will
>cover and protect the seeds like a carpet of mulch. The woody mulch
>together with the new green and the root mass already show signs of
>improving soil quality after only a couple of years.
> I also started collecting stones and logs for building numerous little
>barriers to prevent water from running off (look for “the man who
>harvested water” on the net).
> Regards,
> Dieter Brand, Portugal
>







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