REPORT / INTERNATIONAL NEWS

The researchers analyzed data from dozens of studies to determine how planting new biofuel crops can influence the carbon content of the soil.

Plants use the sun's energy to convert carbon dioxide from the atmosphere into the organic carbon that makes up leaves, stems and other plant parts. As plants decay, this carbon goes into the soil. Organic carbon is an important component of soil health and also influences atmospheric carbon dioxide levels. Whenever the soil is disturbed, as occurs when land is plowed or cleared of vegetation, some of this carbon returns to the atmosphere in the form of carbon dioxide.

Unlike corn, which must be replanted every year, perennial grasses such as switchgrass and Miscanthus preserve and increase carbon stores in the soil. These and other grasses have been proposed as high-energy alternative feedstocks for biofuel production.

These findings appear in December 2008 in the journal Global Change Biology Bioenergy.