WASHINGTON, Oct. 26 (Xinhua) -- Agricultural soil
erosion is not contributing carbon dioxide to the atmosphere, according to
research published Friday in the online edition of journal Science.
The study was carried out by an international team of
researchers from the University of California Davis, the Catholic University of
Leuven in Belgium and the University of Exeter in Britain.
They found that erosion is equal to about 1.5 percent
of annual fossil-fuel carbon emissions worldwide.
Carbon emissions and other greenhouse gases are
causing worldwide concern because they trap heat in the Earth's atmosphere, a
major contributor to global climate change.
Earlier studies suggested a broad range of erosion
effects, from erosion equaling 10 percent of fossil-fuel emissions and up to an
equivalent of 13 percent.
The team readjusted previous estimates of the amount
of carbon emissions.
"Some academics have argued that soil erosion causes
considerable emissions of carbon, and others that erosion is actually offsetting
fossil-fuel emissions. Now, our research clearly shows that neither of these is
the case," said lead author Kristof Van Oost of the Catholic University of
Leuven.
In their study, the researchers found that erosion
acts like a conveyor belt, excavating subsoil, passing it through surface soils
and burying it in hollows downhill. During its journey, the soil absorbs carbon
from plant material; when the soil is buried, so is the carbon. Erosion,
therefore, creates what can be described as a "sinking" of atmospheric carbon.
Still, the researchers said, erosion is a problem
that must be addressed, because it has a detrimental effect on agricultural
productivity and the surrounding environment.