Conventional lawns and global warming

New research has found that mowing and other lawn maintenance emit almost as much or more greenhouse gases than the well-tended grass extracts from the air.

The researchers took and evaluated soil samples over time to ascertain carbon storage, or sequestration, and they determined nitrous oxide emissions by sampling air above the turf. Then they calculated carbon dioxide emissions resulting from fuel consumption, irrigation and fertilizer production using information about lawn upkeep from park officials and contractors.

The study shows that nitrous oxide emissions from lawns are comparable to those found in agricultural farms, which are among the largest emitters of nitrous oxide globally.

In ornamental lawns, nitrous oxide emissions from fertilization offset just 10 percent to 30 percent of carbon sequestration. But fossil fuel consumption for management, the researchers calculate, releases about almost as much or more carbon dioxide than the plots can take up, depending on management intensity. Athletic fields fare even worse, because — due to soil disruption by tilling and resodding — they don't trap nearly as much carbon as ornamental grass but require the same emissions-producing care.

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http://www.agu.org/news/press/pr_archives/2010/2010-02.shtml