by Mary Travaglini
Sometimes people ask, “Aren’t lawns bad for the environment?” Turns out that’s not true, especially if the lawns are organic and have healthy soils. Here are some of the benefits of an organic lawn with healthy soils, and the science behind them:
Healthy lawns offset climate change
Natural grasslands can store more carbon than most forests. Up to a third of grass roots die every year, and the blades die annually. The organic matter left by dead roots and grass clippings are digested by microorganisms. Much of that organic matter is converted to humus, which is a stable organic matter that stores carbon below ground. While trees store a lot of carbon in their wood and roots, they don’t die in large amounts each year, and their leaves are recycled quickly back into plant nutrients for the tree.
Ever heard of a teragram? A teragram (or megaton) is equal to 2,204,622,621 pounds. The Great Pyramid at Giza weighs a massive 6 teragrams. The United States emits 6,870 teragrams of carbon dioxide each year through the burning of carbon-based fuels like coal and oil.
The United States has an estimated 50,000 square miles of lawn, about the size of Alabama (NASA). If all existing U.S. lawns were organic and had healthy soil biology, they could store up to 16.7 teragrams of carbon dioxide each year.
An easy way to offset climate change is to always leave grass clippings—taking them off the lawn can reduce carbon capture by 60%.
Healthy lawns contribute to air quality
Hundreds of millions of tons of dust circles the earth annually (Griffin et al. 2003, Aerobiologia Vol. 19) and is a serious atmospheric pollutant. Grass blades capture many air-borne particles, and when rain and dew wash dust from the leaf blades to the ground, microbes then help break the pollutants down or bind them in the soil. Just in Maryland, lawns remove an estimated 12 million tons of dust and dirt annually (Maryland Institute of Applied Agriculture), and they continue to trap debris year-round, when the deciduous trees lose their leaf surfaces to do so in the winter.
Pollutants in the atmosphere can also make rainfall acidic, which is harmful to aquatic life in our streams and water bodies. When rainfall filters through a healthy lawn, acidity can be reduced to one-tenth of its original levels (Maryland Institute of Applied Agriculture).
Lawns are 10 to 14 degrees cooler than surrounding paved surfaces, and better than paved surfaces along roadways or in some urban areas where trees are not a good fit. They will also help cool adjacent surfaces, like driveways, walls, and buildings.
Healthy lawns produce oxygen
Surprisingly, lawns can produce more oxygen than mature trees per acre. An acre of grass produces enough oxygen for 64 people a day (Maryland Agricultural Statistics Service), while an acre of trees produces enough oxygen for 18 people a day (Growing Air Foundation). The longer grass and deeper roots of an organic lawn will improve oxygen production. A 50-square foot area of grass produces enough oxygen for a family of four (The Lawn Institute).
On the East Coast, when many of our trees and gardens go dormant in the fall, or are devoid of leaves in the spring, many lawns are green and growing, providing oxygen to improve the air we breathe.
Healthy lawns capture and infiltrate stormwater, and treat pollutants in runoff
Lush turf is six times more effective in absorbing rain than an equivalent field of wheat (Maryland Institute of Applied Agriculture).
When 1” of rain falls, it amounts to 28,000 gallons of water per acre. A soil with a 1% humus content can hold 10,000 gallons of water per acre before it runs off or filters out, but a soil with a 6% humus content can hold 60,000 gallons of water. A 6% humus content soil can soak up almost every drop of rain except in extreme events.
Microorganisms in soils are one of the best treatment systems for the decomposition and binding of pollutants from roadways and urban surfaces, such as heavy metals, chemicals, fuels, and disease-causing bacteria. Their populations will rise with a healthy organic soil content.
Healthy lawns provide erosion control
The tall fescue grasses commonly used as turf in the Northeast and Mid-Atlantic have evolved over millions of years to grow roots as deep as 2 or 3 feet that stabilize the soil. Grasses also grow lateral (sideways) roots, creating a strong, woven mat in the upper layer of the soil.
A 1,000 square foot area of healthy turf grass can have up to 300 million feet of roots, making it nearly impossible for any soil to erode away from a lush lawn.
Make the switch to organic lawn care
Practicing organic lawn care is not difficult!
Organic lawn care involves the same amount of work as a chemical fed lawn – it’s just different steps. For example:
- Instead of heading to the store for synthetic fertilizers, perform a soil test, and use organic amendments.
- Instead of short, frequent watering, water less often, but when needed, water deeply.
- Instead of weed-and-feed or other chemicals to kill broadleaf plants, overseed for a dense lawn to overpower other plants.
- Instead of using a gas-powered mower, switch to electric.
- Instead of bagging clippings and leaves, chop them up to mulch them back into the lawn.
Want an abundance of tips and tools for organic lawn care? Head over to MontgomeryCountyMD.gov/lawns for practical advice.
About the Author
Mary Travaglini is the Manager of the Organic Lawn and Landscape Program, providing direction and oversight for Montgomery County, Maryland’s new organic lawn and landscaping program. Mary has degrees in natural resources and landscape architecture from Cornell University and the University of Michigan, and has previous experience with invasive plant management, landscape design, trail construction, and stormwater management, all of which she applies to educating the public about organic landscaping practices.
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