Lawn turf is America's biggest crop--and a mixed bag for the environment
Americans pour as much as 238 gallons of water per person, per day onto lawns during the growing season. But lush lawns also turn out to be a "sink" for carbon dioxide, pulling the greenhouse gas out of the atmosphere as they grow. The effect is more pronounced when grass clippings are left to decompose in place, boosting growth by providing nitrogen--though offset by the 800 million gallons of gas burned in lawnmowers every year. All told, says Milesi, "the 2 percent of the U.S. land surface that is covered in lawns could account for about 5 percent of the . . . carbon dioxide" absorbed by all plants.
Overkill? Still, that positive effect isn't likely to change environmentalists' minds about the danger posed by so many perfect lawns. Farmers and golf course managers have an economic incentive to conserve resources like water, fertilizers, and pesticides, Milesi notes. "But for the single homeowner," she says, "lawn care is usually not a big part of the budget, so there's a temptation to always do a little more." Outdoor watering accounts for more than half of municipal water use in most areas, and homeowners often apply fertilizers and pesticides to their lawns at many times the recommended levels.
In arid regions, there are usually strict regulations on lawn watering. Fertilizers, which can seep into waterways, have been blamed for excess growth of algae and aquatic plants in lakes and coastal areas. And, citing the potential danger to human health and wildlife, a consortium of environmental groups is pushing large retailers to carry less harmful alternatives to the tens of millions of pounds of insecticides and weedkillers used on private lawns every year.
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