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 Institute.
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 organic farming.
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
Besides leading the work on the historic farming systems
trial, Mader is also the leader of a soil biology research
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.