ENVIRONMENTAL BENEFITS OF GRASSLANDS

Submitted by Herb Manig, American Farm Bureau Federation

Water quality improves as grassland vegetation becomes denser and soil conditions improve. A University of Wisconsin study showed that grasslands are the best "crop" for reducing runoff, erosion, and phosphorus pollution. A similar study done at the USDA-Agricultural Research Service North Appalachian Experimental Watershed at Coshocton, OH showed that both surface and ground water from a grassland watershed was as good as or better than water from the adjacent pristine forested watershed. Grassland soils are an excellent biological filter to recover nutrients passing through the soil. Grass roots are active almost year-round and can recover nutrients from the soil that can leach out from other land uses.

Because of their permanent and diverse plant cover, grasslands provide good habitat for wildlife as well as forage for livestock. Research has consistently shown that ground-nesting birds and small mammals thrive in properly managed pastures. Grazing lands can provide nesting habitat, cover, and food when adequate plant residues remain following grazing or mowing. Research has shown that grazing animals can be used to manage streambank vegetation to enhance fish populations. Studies in Minnesota and Wisconsin resulted in fish populations two to three times greater in streams inside pastures where cattle were being grazed in a management-intensive grazing system compared to pastures where cattle were totally excluded from the streams.

The "greenhouse effect" is the warming of the Earth's atmosphere due to increased levels of some gases (primarily carbon dioxide) that allows incoming short-wave radiation from the sun to reach the Earth, but absorbs the outgoing long-wave radiation from Earth's surface back to space. Grassland soils are a tremendous reservoir for storage of this organic carbon. Think of them as "carbon sinks." The top meter of soil worldwide contains almost double the amount of carbon contained in vegetation and the atmosphere.

Total organic carbon is twice as abundant in prairie soil as in forest soil. In grassland ecosystems, more than 90% of the organic matter produced is found in the roots, while more than half of the organic matter in a forest ecosystem is above-ground. Grasses and legumes use atmospheric carbon as building blocks for plant tissue. The unutilized and decomposed plant tissue is returned to the soil and becomes part of the carbon pool. This process helps reduce carbon dioxide levels in the atmosphere and reduces the "greenhouse effect." A permanent grassland ecosystem stores significantly more soil carbon than cropland areas do. Any initiative that support grassland agriculture will, over the long term support an effective carbon sink.

* source: Ohio Livestock Environmental Assurance Program - Level 1