Different approaches to studying
the comparative impacts of organic and other cropping systems in
side-by-side plots give soil specialists lots to talk about. That
was clear when Paul Mader, PhD, spent a day recently at The Rodale
Mader is the research leader of the DOK (Biodynamic, Organic and
Conventional) crop systems trial in Therwil, Switzerland, the world’s
longest-running trial comparing organic and conventional farming
systems. A plant pathologist by training, Dr. Mader obtained a PhD
at University of Basel in 1988. Since 1989, he has been with FiBl
(the Organic Research Institute in Switzerland), which runs the
DOK trial. FiBl has 60 scientists and 60 support staff working on
organic agriculture in Europe, Africa and India, with an annual
budget of about $20 million.
Mader, who was in Pennsylvania to attend the World Soil Science
Congress in Philadelphia, said the European Union is quite supportive
of organic agriculture. In his own home country, he said, 6,500
commercial organic farms cover nearly 11 percent of all arable acreage.
While visiting The Rodale Institute, Mader spoke with staff and
reviewed programs, then gave a seminar on soil life and crop highlights
from the DOK trials and discussed the role of reduced tillage in
Like the Rodale Institute’s long-term Farming Systems Trial—which
began in 1981 compared to DOK’s start date of 1978—the
Swiss trials mimic real farming practices. There are also about
250 farm collaborators. “Farmers helped to plant this experiment
from the very beginning and still help us to guide the comparison
trial,” said Dr. Mader. The DOK trials compare biodynamic,
organic and conventional farming.
Besides leading the work on the historic farming systems trial,
Mader is also the leader of a soil biology research team.
In a study accepted for publication in Science magazine,
Mader explains how an organic farming approach that reduces inputs
by 50 percent can maintain 80 percent of conventional yields while
both improving soil biological diversity and reducing environmental
impacts of agricultural production. Work at The Rodale Institute,
which is geared to optimize organic inputs through compost and cover
crops, has been of interest for showing no yield decrease for organic
production compared to conventional farming, along with substantial
gains in soil organic matter.
The land where the DOK trials are taking place was previously in
conventional grass and clover, Dr. Mader said. “It could be
that we are still in a conversion process and that equilibrium has
not yet been reached.”
Some key findings of the DOK study:
- Erosion was less of a factor in the biodynamic and organic
systems than in the conventional system.
- A close correlation exists between aggregate stability and
soil microbial biomass.
- Organic material decomposed more rapidly in a biodynamic
system compared to a mineral-based system.
- A greater diversity of the microbial soil population and
larger animal species—such as earthworms and insects—had
a positive impact on plant growth and vigor, soil structure
and carbon cycling.