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Preserving Weed Seeds for Science
August 4, 2003
While the rest of the farm crew removes weeds, Ruth Mangum is
busy planting them on the 7,000-acre Henry A. Wallace
Beltsville (Maryland) Agricultural
Research Center. Mangum is curator of one of the country's oldest and most
extensive weed seed collections at the center, part of the
Agricultural Research Service.
During the summer of 2002, Mangum planted seed from all 30
pigweed types in the collection. She irrigated the pigweed and hand-pulled
other competing weeds, giving the pigweed some of the tender loving care
normally reserved for farm crops. She would give them even more care, but weeds
do better with less--for example, they don't need fertilizer.
The collection, now up to 290 lots of seeds, began in the 1960s.
Mangum is now moving into her 24th year as weed "librarian." She "lends" seed
to researchers around the country, much as a librarian lends books. Also, like
a librarian, she keeps a record of what she sends. But she doesn't want the
seeds returned--she wants to be able to send more from the same seed lot, if
Mangum and colleague John Teasdale, at the ARS
Systems Laboratory in Beltsville, see the collection as a key tool in
helping researchers learn how to control weeds better.
On September 17, Teasdale will present a paper, co-authored by
Mangum, ARS agronomist Jay Radhakrishnan and ARS soil scientist Michel
Cavigelli, also with the Sustainable Agricultural Systems lab, on buried weed
seeds under different farming systems--including organic farming--for a weed
seed conference. Held at the University of
Reading, United Kingdom, it's sponsored by the Association of Applied
Biologists, in association with the European
Weed Research Society.
In the meantime, Mangum hopes the farm crew forgives her for the
inevitable pigweed that may escape from her fields during subsequent
For more information on the weed seed collection, see the
August issue of
Agricultural Research magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.