15, 2004: Biologically based weed management is the
focus of a new research partnership between the USDA Beltsville
Agricultural Research Center's Sustainable Agricultural Systems
Lab, Pennsylvania State University's Weed and Agroecology Lab
and The Rodale Institute.
The term biologically based weed management refers to weed management
strategies that focus on weeds' biological or ecological attributes—germination
requirements, growth habits, reproductive cycles, etc.—in
order to minimize their impact on crops.
Typical biologically based weed management strategies include
rotating crops to break up tillage patterns, selecting crop
varieties with good competitiveness and weed tolerance characteristics,
and incorporating cover crops for weed suppression.
Other weed management strategies, such as field preparation
and cultivation, are not strictly biologically based but can
still be perfected by taking agroecological factors into account.
The research partnership is projected to extend for four
years and will integrate lab, field, and on-farm experiments.
"People tend to think of herbicides as relatively benign
pesticides, but recent studies are linking them to extremely
serious environmental and human health problems," says
TRI research manager Dr. Paul Hepperly. "And they are
used in vast quantities. There is an urgent need to develop
effective alternative weed management strategies for organic
and conventional farmers alike." The effort is particularly
timely, Hepperly notes, as more and more weeds are developing
At USDA-BARC, the project will be overseen by Dr. John Teasdale,
research leader for the Sustainable Agricultural Systems Lab.
Teasdale has been a strong advocate for sustainable agriculture
and reduced tillage research and has helped pioneer the investigation
of vinegar as an organic herbicide.
At Penn State, the project includes fellowship funding for
two graduate students working in the Weed and Agroecology
Lab, a division of the Department of Crop and Soil Sciences.
Both will be overseen by Dr. David Mortensen, an associate
professor of weed ecology and director of PSU's Sustainable
Agriculture and Crop Ecology Program.
Work at The Rodale Institute related to the new initiative
will fall into four project areas: variety trials focusing
on weed-crop interactions; weed management in organic no-till
systems; weed seed dynamics and the effects of using composted
versus raw manure; and on-farm research to document and analyze
the best weed management strategies practiced by innovative
farmers in Maryland and Pennsylvania.
Each of these areas builds on previous research conducted
at The Rodale Institute. Variety trials for weed competitiveness
in corn, soybeans, wheat and barley were begun in 2003 and
continued in 2004. A major goal of the variety trials is to
identify and quantify crop traits linked to high yields in
the face of weed pressure—traits such as early vigor,
early canopy closure, allelopathy, and weed tolerance.
As reported elsewhere on NewFarm.org, weed management through
the use of cover crops has long been among Rodale Institute
farm manager Jeff Moyer's primary objectives. In 2003, Moyer
and others designed and built a cover-crop roller to mechanically
kill standing cover for no-till planting without the use of
chemical herbicides. Ongoing trials are centered on optimizing
cover crop management—seeding rates, seeding patterns,
and species mixes—to suppress weeds.
Historic and continuing data from The Rodale Institute's
Farming Systems Trial and Compost Utilization Trial will be
put to use in the compost and weed seed dynamics research
area. In addition, new data will be collected regarding weed
seed populations in unfinished and finished compost and in
fields previously amended with unfinished and finished compost.
This work will be closely coordinated with researchers at
the Weed and Agroecology Lab at Penn State.
Finally, TRI researcher Dave Wilson will work with John Teasdale
at USDA-BARC to coordinate an on-farm research area designed
to quantify best the weed management practices of farmers
in Pennsylvania and Maryland. Both organic and sustainable
farmers will be recruited and their practices will be documented
and publicized for the benefit of others. "Ideally, this
group will include farmers potentially interested in transitioning
to organic," says Wilson. "There may be old-fashioned
knowledge and skills out there that we may want to bring back,
or combine with the latest tools and innovations."