| July 29, 2005, ARS News Service:
Carbon stored in soil during the first five years of bermudagrass
management was two to three times greater when the grass was grazed
than when it was harvested for hay or left unharvested, according
to Agricultural Research Service (ARS) scientists.
Carbon dioxide in air is important for life on earth, but its rapidly
rising concentration is cause for concern, because of its contribution
to the greenhouse effect and potential global warming. Maintaining
more carbon in soil means less of it escapes into the atmosphere.
Ecologist Alan Franzluebbers and animal scientist John Stuedemann
of ARS found that cattle grazing on forage grasses could help improve
carbon storage in soil. In studies at ARS' J. Phil Campbell, Sr.
Natural Resource Conservation Center in Watkinsville, Ga., they
found that adding cattle grazing to a crop rotation system can be
beneficial by enriching the soil with carbon and other nutrients.
Also, income could be generated from the cattle.
In Georgia, plowing and other practices have resulted in lost top
soil. Fortunately, permanent pasture now accounts for about 18 percent
of land area in the southeastern states, compared to 20 percent
for cropland. Converting land to permanent pasture has significantly
reduced soil erosion.
In most instances, crop farming and cattle farming are separate
operations. Franzluebbers and Stuedemann envision a system where
calves could be raised on pasture in rotation with other crops like
corn or wheat. The type of crop would determine when grazing would
According to the researchers, putting as little as 10 percent of
existing cropland in rotation with grazing could significantly reduce
costs, due to lower inputs such as herbicides, and generate additional
income from the livestock. The next step for the researchers is
looking at long term integration of annual crops with perennial
ARS is the U.S. Department of Agriculture's chief scientific research