When it comes to reducing carbon footprints, many Americans need look no further than their front yards. The soil beneath those perfectly manicured carpets of green grass—the pride of many suburban homeowners—is pumping surprising amounts of carbon into the atmosphere. That's according to a study published this month in the Soil Science Society of America Journal, which concludes that the amount of carbon rising from the soil of residential lawns is significantly greater than that from the soil of agricultural land—in this case, irrigated fields of corn. Researchers (inset) at Elizabethtown College in Pennsylvania measured weekly carbon emissions from nearby residential lawns and commercial cornfields from October to December 2011. They found that carbon emissions from the soil in suburban lawns were as much as twice as high as those from cornfields. Carbon is naturally deposited into soil by dead plant matter. When those plants begin to decompose, it is released back into the atmosphere as carbon dioxide, where it contributes to climate change. But don't trade in your lawnmower just yet. Moisture, along with warmer temperatures, increases the amount of carbon released from the soil, and the authors say that their findings are due—at least in part—to higher soil temperatures in the lawns rather than the grass itself. Warmer soil temperatures are an unavoidable consequence of urban development, leaving little the typical suburban or urban homeowner can do to reduce the amount of carbon emanating from their lawn. However, trees and other vegetation remove those gases from the atmosphere, so lush landscaping is the best way to mitigate the effects of human warming and achieve a carbon neutral yard.
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