By Christopher Ingraham
4 August 2015
(Washington Post) – A recent essay by an Ohio woman who refuses to mow her lawn has struck a nerve. Thirteen hundred people have weighed in with a comment on Sarah Baker's tale of flouting a neighborhood mowing ordinance in the face of a $1,000 fine.
As Baker notes in her essay, lawns are a big part of contemporary American life. There are somewhere around 40 million acres of lawn in the lower 48, according to a 2005 NASA estimate derived from satellite imaging. "Turf grasses, occupying 1.9% of the surface of the continental United States, would be the single largest irrigated crop in the country," that study concludes. Conservatively, American lawns take up three times as much space as irrigated corn. The authors mapped the entirety of the nation's turf grass, below. You'll notice that it's basically a population density map of the U.S. — where there are people, there are lawns.
You'll notice, if you look closely, that the colors start at light green in the urban cores and get darker as you move outward — lawn density increases in the suburbs.
In some states, a significant chunk of the landscape is covered in turf grass — meaning residential lawns, commercial lawns, golf courses, and the like. Delaware is 10 percent lawn. Connecticut and Rhode Island are 20 percent. And over 20 percent of the total land area of Massachusetts and New Jersey is covered in grass, according to that 2005 NASA study.
Perhaps not surprisingly, the traditional American lawn has come in for some scrutiny in recent years. Some, like Baker, are abandoning regular lawn maintenance out of environmental concerns — lawns require fertilizer to grow and gas to mow, and they take up space that could otherwise be used for animal habitat.
Other folks are ditching their lawns because of the amount of water they soak up — 9 billion gallons of it per day, according to the EPA. Think of the miracle that is the modern water supply — pristine water pumped hundreds of miles, passed through shiny state-of-the-art filtration systems, treated with miracle chemicals that keep our teeth from falling out of our heads, and available on-demand at the twist of a knob. And then consider that we intentionally dump billions of gallons of that water out on the ground!
These reasons are all well and good enough. But if you're an average lazy American like me, with kids and a dog and maybe a mortgage and probably a job too, these may seem like valid concerns but they're probably not worth changing your behavior over. So consider the most compelling reason to ditch your lawn, or to at least scale it back: time. [more]
ABSTRACT: Turf grasses are ubiquitous in the urban landscape of the United States and are often associated with various types of environmental impacts, especially on water resources, yet there have been limited efforts to quantify their total surface and ecosystem functioning, such as their total impact on the continental water budget and potential net ecosystem exchange (NEE). In this study, relating turf grass area to an estimate of fractional impervious surface area, it was calculated that potentially 163,800 km2 (+/- 35,850 km2) of land are cultivated with turf grasses in the continental United States, an area three times larger than that of any irrigated crop. Using the Biome-BGC ecosystem process model, the growth of warm-season and cool-season turf grasses was modeled at a number of sites across the 48 conterminous states under different management scenarios, simulating potential carbon and water fluxes as if the entire turf surface was to be managed like a well-maintained lawn. The results indicate that well-watered and fertilized turf grasses act as a carbon sink. The potential NEE that could derive from the total surface potentially under turf (up to 17 Tg C/yr with the simulated scenarios) would require up to 695 to 900 liters of water per person per day, depending on the modeled water irrigation practices, suggesting that outdoor water conservation practices such as xeriscaping and irrigation with recycled waste-water may need to be extended as many municipalities continue to face increasing pressures on freshwater.