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  • From: "TradingPostPaul" <tradingpost@riseup.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] No-till, Permanent Bed Farming, by Ken Hargescheimer
  • Date: Mon, 01 Jan 2007 19:50:05 -0700


No-till, Permanent Bed Farming
Countryside magazine August 2002

INCREASE YIELDS WITH GREEN MANURE AND COVER CROPS
http://www.countrysidemag.com/issues/4_2002.htm
KEN HARGESHEIMER

The odyssey of my colleagues and I started in 1982, the day Conrado Zavala,
a villager in Central America, sheepishly showed us his experiment.
Skeptical about the value of the organic matter we had recommended, he had
piled a huge quantity of compost into several rows of his maize field. The
last two rows he left as a control, untilled and unfertilized. There,
before our eyes, stood a field of maize 2-1/2 meters tall, with the last
row less than 40 cm tall. That was the day we began to realize the
incredible degree to which organic matter can restore soils.
Maximize organic matter production

Little by little, work in a dozen countries has convinced us that the vast
majority of soils can be made highly fertile. How? By using our first
principle: maximize organic matter production.

Conrado's particular approach, however, was anti-economic. The cost of
using compost on basic grains exceeds the benefit. But intercropped green
manure/cover crops (gm/cc's) can produce from 50 to 140 tons per hectare
(green weight) of organic matter with very little work: no transporting of
material and no cutting up, layering or turning over of compost heaps. In
fact, sometimes, because of the gm/cc's control of weeds, net labor costs
decrease. And soil quality often improves visibly each year. Then, as often
happens, we found we were far from the first to employ intercropped
gm/cc's. Gradually, between 1985 and 1992, we learned that villager farmers
from Veracruz State in Mexico through Guatemala, El Salvador and Honduras
were intercropping velvetbeans (Mucuna pruriens), cowpeas (Vigna spp.) and
jackbeans (Canavalia ensiformis) with their maize and sorghum.
Keep the soil covered

To our amazement, these systems, virtually all of them in the supposedly
infertile humid tropics, allow farmers to plant maize every year for
decades, with productivity increasing over time up to four tons per
hectare. In other words, these farmers have found an answer to
slash-and-burn agriculture. Migratory agriculture is most frequently
motivated by decreasing fertility, increased weed problems, or both. In the
Mesoamerican gm/cc systems, nitrogen fixation and biomass recycling
maintain soil fertility. Mulches of crop residues and fast-growing gm/cc's
drastically reduce the weed problem. We had learned a second principle:
keep the soil covered.

Gm/cc mulches provide a whole series of additional benefits. They protect
the soil from irradiation and the heat of the tropical sun, thereby also
reducing burnout of organic matter. They save a tremendous amount of work;
farmers can sow into the plant residue rather than tilling the soil. They
keep the excess nitrogen from acidifying the upper soil horizons. And they
largely prevent soil erosion, even on slopes of 40 degrees. In the
meantime, we had been reading Fukuoka's book, The One-Straw Revolution.
However, his recommendation of zero tillage failed to convince us. After
all, most of the traditional agriculture in Latin America uses zero
tillage, yet is far from productive. In mid-1993, I visited the work of
EPAGRI in southern Brazil.

Having visited over 160 agricultural development programs through the
years, I found this largely unpublicized effort to be the finest of its
size I had seen in Latin America. Literally tens of thousands of farmers
were producing harvests approaching those in the U.S.-with gm/cc's and zero
tillage.
Zero tillage

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.
Maintain biological diversity

EPAGRI's investigation and dissemination of over 60 species of gm/cc partly
to avoid diseases and insect pests, confirmed another, more widely known
fourth principle: maintain biological diversity.

This last principle was discovered by Martha Rosemeyer, a Cornell doctoral
candidate working in Costa Rica. For several years, agronomists working
with a low-cost, traditional, mulched-bean (Phaseolus vulgaris) system had
been trying to solve a phosphorus deficiency problem. With highly acid (pH
= 4.0 to 4.5) soils, virtually all the phosphorus applied became tied up
almost instantly. Farmers' harvests averaged 500 kgs/Ha.
Feed plants through the mulch

Martha and a group of farmers tried broadcasting the phosphorus on top of
the mulch. The results, since confirmed in numerous additional experiments,
were astounding. Bean yields rose to between 1.5 and 2.5 T/Ha. This would
help explain the success of Mesoamerica's gm/cc systems, and coincides with
the fact that plants as diverse as maize, manioc, and tropical trees tend
to develop a heavy mass of feeder roots immediately under thick mulches.
Furthermore, it makes simple sense: when soils are as hostile to plant
growth as are the humid tropic's acid soils, feeding plants through a mulch
would seem a much more promising alternative. The fifth principle is
undoubtedly the most unconventional: feed plants through the mulch.

These five principles enjoy a nice synergy. For example, if we are going to
feed our plants through a mulch, we certainly cannot plow our fields.
Nevertheless, the most important relation between these principles is
precisely the one that took us the longest to figure out: They describe
quite well the way a humid tropical forest functions. That is, all we
discovered in our 12-year odyssey is something we should have guessed all
along. In order for humid tropical agriculture to be both highly productive
and sustainable, it must imitate the highly productive,
millions-of-years-old humid tropical forest (Roland Bunch, COSECHA,
Honduras).

The above works in temperate climates as well. In Honduras, farmers,
working alone and using hand tools only, farm up to 10 acres using no-till.
In a video that trains extension service people, the statement is made "The
worst thing that can happen to a soil is the use of a rototiller." Or a
mouldboard or oneway or disk, etc. [KH]

Morrison, an ag engineer in Temple, TX, did several years of research with
100" wide permanent beds using farm machinery. He later used 80" and 40" to
accommodate harvesting equipment. It increased yield 10%.
No-till beds

No-till is great once the soil is loaded with organic matter and has become
healthy with microbes and earthworms. Walking on and compacting the soil
will ruin them so you need to establish permanent walkways and beds.
Keeping mulch on the ground year-round is critical with any garden. Without
mulch, rain can compact and erode the soil.

To do the plant-through-the-mulch procedure, you'll have to start by
planting the cover crop. Cut the plants off in the spring, leaving the
cuttings on the soil to serve as a mulch. Then plant the tomatoes or other
crops right into the undisturbed roots without tilling or adding
fertilizer. Additional mulch might need to be added after planting if any
soil is left exposed.

Tests by the USDA showed that this technique gave a 100% increase in
production over conventional fertilizer and tilling. (Howard Garrett,
dirtdoctor.com, Dallas Morning News, 3 March 00.)

The above principles apply to very steep field. In Honduras I visited a
farm on land with a 73ยบ slope. During Hurricane Mitch, when almost a
meter of rain fell in just a few days, this farm had no soil erosion with
the permanent beds. They had been built some six years before. Each bed was
approximately one meter wide with each bed some one meter below the next
one and on the contour. A small channel to carry runoff water, when it was
needed, was on the uphill side of each bed. Each bed was made to slope just
a little to the channel. On less-sloped land the beds could be wider. No
grass, rocks, trees, alley cropping, etc., were used.

Ken teaches workshops in organic, no-till mini-agriculture (urban and
rural): gardening, mini-farming, mini-ranching worldwide in English and
Spanish.







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