|October 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 herbicide resistance.
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
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."