Managing Cattle Operations to Protect Lakes and Rivers
February 6, 2008
Concerns about long-term effects of
beef cattle browsing more than 11 million acres of Florida grazinglands led
Agricultural Research Service (ARS)
scientists to examine soil fertility changes in bahiagrass-based beef cattle
pastures from 1988 to 2002. Analysis of data from that research shows that
cattle can be managed in an environmentally safe way, despite the large
quantities of waste the animals generate.
Forage-based livestock systems have been cited as a major cause of
deteriorating water quality in Florida and other cattle-producing states.
Phosphorus runoff from manure and fertilizers applied to enhance forage
production can pollute rivers and lakes. However, very limited data have been
available to quantify nutrient losses to adjacent bodies of water from pastures
managed for grazing and hay production.
For this long-term monitoring study, the pastures were managed for spring
grazing and late- summer haying. Soil scientist
C. Sigua and colleagues in the
Beef Cattle Research Unit in Brooksville, Fla., monitored changes in soil
nutrients. The data they generated enabled them to predict soil chemical and
physical changes likely under continuous forage-livestock cultivation, and to
devise measures to manage them.
Testing was done in three large pasture units with a combined area of about
3,800 acres, of which about 3,200 acres were in permanent pasture. The herd
used in the studyabout 1,000 cows, bulls and calvesis maintained
for nutritional, reproductive and genetic research at Brooksville.
Overall, there was no buildup of soil phosphorus or other crop nutrients,
despite the annual application of fertilizers and daily in-field loading of
animal waste. Periodic soil analysis showed declining nutrient levels,
especially of phosphorus.
Next, Sigua and other collaborators will integrate environmental, plant and
animal genetic resources into a sustainable beef cattle-agroecosystem suitable
for the subtropical United States. The goal is to optimize forage-based
cow-calf operations to improve pasture sustainability and protect water
more about this research in the February 2008 issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.