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Editors' note:
As New Farm Research and Training
Manager at The Rodale Institute, Dr. Paul
Hepperly has been a regular contributor
to NewFarm.org for some time, providing
research updates, op-ed pieces, and white
papers on topics like carbon sequestration
in organic farming systems.
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None of those venues do full justice to
the range of Paul's experience, however.
Paul grew up on a family farm in Illinois
and holds a Ph.D. in plant pathology, an
M.S. in agronomy and a B.S. in psychology
from the University of Illinois at Champaign-Urbana.
He has worked for the USDA Agricultural
Research Service, in academia, and for a
number of private seed companies, including
Asgrow, Pioneer, and DeKalb. He has overseen
research in Hawaii, Iowa, Puerto Rico, and
Chile, and investigated such diverse crops
as soybeans, corn, sorghum, sunflowers,
ginger, and papaya. He has witnessed the
move toward biotech among the traditional
plant breeding community and the move toward
organics among new wave of upcoming young
farmers. Beford coming to the Rodale Institute
Paul worked with hill farmers in India to
help them overcome problems with ginger
root rot in collaboration with Winrock International.
Now we've decided to give Paul his own
column, in which he can report on agricultural
research from around the world and reflect
on its relevance to The Rodale Institute's
research program and to the progress of
sustainable agriculture more generally in
light of his own broad perspective. Enjoy.
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November
19, 2004: The Organic Farming Research Foundation
in Santa Cruz, California, has been supporting organic
farming by funding grants for research and education projects
since 1994. In their most recent Information Bulletin
(Fall 2004, no. 14), they feature an article entitled
"Long-term Organic Farming Impacts on Soil Fertility,"
by Professor Jessica Davis of Colorado State University.
This OFRF-funded project took a look at Grant Family Farms,
the largest organic mixed-crop farm in Colorado. The researchers
focused on the transformation of soil fertility under
organic farming management, following 12 fields in 3,
five-year periods from 1985 to 2000.
To assess the impact of transitioning to organic in
these fields, soil acidity, electroconductivity, organic
matter, phosphorus, potassium, zinc, iron, manganese,
copper and nitrates were measured. Under organic management,
fields received cover crop green manure as well as periodic
dairy manure applications. With the exception of this
study, there are few long-term studies of organic farming
in the semi-arid climates of eastern Colorado and the
Great Plains.
Conventional and organic practices were contrasted
in one case in the same field under conventional management
from 1972 to 1979 and after transition to organic from
1985 to 2000. Under conventional production, soil pH
increased from 8.1 to 8.3, while organic matter fell
from 2.6 to 1.5 percent. Phosphorus was at very low
levels (1 lb/ac or less) and potassium shrank from 226
to 154 lbs/acre. Zinc, manganese and copper were also
low and diminishing from 1972 to 1979.
Under organic management from 1985 to 2000, however,
soil pH fell from 8.2 to 7.9 while organic matter rose
from 2.3 to 3.0 percent. These changes were associated
with large increases in phosphorus, potassium, zinc,
iron, manganese, and copper. At the same time, nitrate
nitrogen did not increase in organic production in this
or any of the test fields.
Increasing soil organic matter is crucially important
to improving the chemistry of the soils. Jessica Davis
and her co-workers had hypothesized that equilibrium
would occur and soil fertility improvements would stagnate.
However, her experimental evidence did not support this
contention, for 30 years of soil building under organic
agriculture did not show any evidence of decreasing
soil fertility improvement.
Because organic farming locks carbon in the soil, it
is a vital tool in moderating runaway greenhouse gases.
The doubling of soil organic matter from 1.5 to 3.0
percent in this carefully monitored before and after
case study underscores the magnitude of this potential.
Despite persistent voices suggesting that soil improvement
and organic management has limited scope for moderating
environmental conditions, hard data like these point
to a different conclusion.
With this in mind, we prefer to view soil building
not as a limited process and soil as a limited resource,
but rather as a dynamic and resilient entity with the
ability to grow and expand under appropriate biological
action, management, and genesis. |
