The Environmental Impact of Grazing Cattle

A debate is raging over cattle grazing. It's not about fencing or predators; it's about environmental impact. And the cow is in the crosshairs.

Some environmentalists are calling for a vegan diet, as industrial cattle operations are a major greenhouse gas emitter. But others, like Allan Savory, argue that over history herds of wild creatures have grazed the earth's grasslands. His dream is to regenerate worn out pastureland through managed grazing that mimics nature.

Fortunately, we have some local experts who are collecting data on the benefits of managed grazing.

Every three years, usually from January to March when soils are moist, Biologist Kelly Weintraub measures the soil carbon content, bulk density (a measure of soil compaction), and water infiltration rate. That spring, she conducts plant surveys at the same locations where soils were sampled. Bird surveys are conducted each year, and the presence or absence of key species are used as indicators of important habitat elements, such as snags.

She shared her graphs showing improvement on the soil in just three years. There is more organic matter, increased carbon sequestration and less compaction. In fact, she points out that a one percent increase in soil organic matter can hold an additional 16,500 gallons of water per acre, an important result for some 63 million acres of parched California grasslands.

Equally impressive are the plant diversity results. She found that the regrowth after intensive grazing had fewer invasive plants and more grasses, forbs (wildflowers) and legumes. It is as if the grazing cattle did the rototilling with their hooves, mixed in all the organic matter and produced topsoil that supported the menu of plant life that the cattle could enjoy in the next round of grazing.

If intensive grazing was adopted on the thousands of acres of currently grazed rangeland – Savory reports that about one-third of the world's land surface is grassland – the carbon capture results and soil improvements could be dramatic in reducing global warming.

- The above is excerpted from the article, A happy marriage for cattle and pastureland.

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