Midwestern Weed May Inspire Newfound Respect
By Jan Suszkiw
November 1, 2006
Soybean farmers in the Midwest have
little use for field pennycress. But that may change. Agricultural Research
Service (ARS) scientists in Peoria, Ill.,
are eyeing the annual winter weed's seed as both a biodiesel resource and
ARS research leader
Isbell notes that seed of pennycress, Thlaspi arvense, is 36 to 40
percent oil by weight. Additionally, long-chain fatty acids derived from its
oil are similar to those of other biodiesel resources, including animal fats
and soybean and sunflower oils. Biodiesel from these sources can be used alone
or mixed with petroleum-based diesel to lower the emission of hydrocarbons,
carbon monoxide and other pollutants in engine exhaust.
This winter, Isbell and colleagues at the ARS National Center for
Agricultural Utilization Research (NCAUR)
in Peoria hope to convert pilot-scale amounts of pennycress oil into biodiesel
so that they can further examine its characteristics. This hinges on the
successful harvest of a 10-acre pennycress crop grown near Hanna City, Ill.,
expressly for that purpose.
But why bother, if soybeans can be used? One reason is that pennycress and
soybeans often share the same crop fields. Farmers try to oust pennycress by
spraying herbicide in the spring before planting soybeans, but the weed has
already produced seed by then. Treating it as another crop rather than a weed
could enable farmers to use their land to produce fuel in the winter from
pennycress and food in the summer from soybeans, notes Isbell.
Pennycress' seed production1,500 to 2,000 pounds per acrecould
be well-suited to biodiesel applications. Isbell estimates oil from 1,000
pounds of seed will yield 50 gallons of biodiesel.
Crushed seed left over from biodiesel production, called meal, also has
promise as an organic fertilizer and soil fumigant for low-acreage, high-value
crops, reports NCAUR researcher
Vaughn. In field tests, the seedmeal's decomposition released allyl
isothiocyanate and other substances that kept sicklepod and other weeds from
ARS is the U.S. Department of
Agriculture's chief scientific research agency.