Environmental Benefits of a Healthy, Sustainable Lawn
Lawn areas around homes help provide for a family's outdoor recreational needs. They provide aesthetically pleasing backdrops for other landscape plantings as well as many environmental benefits. One of the most significant of these is the ability to stabilize soil against water and wind erosion. For these and other reasons mentioned below, lawn areas are an important part of preserving and protecting soil, air, and water resources.
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Turfgrass and Water Quality 
As an ever increasing proportion of our society resides in urban and suburban areas, there is a corresponding increase in the amount of paved and other impervious surfaces. Consequently, large amounts of poor quality storm water runoff are quickly channeled to storm sewer systems that dump directly into nearby lakes, streams and rivers. This can significantly contribute to decreased water quality in the receiving water bodies through sedimentation and pollution. Our lawn grasses provide one of the most effective groundcovers available to prevent erosion and increase water infiltration into the soil. |
Research over the last ten years has demonstrated that storm water runoff from a healthy, relatively dense lawn rarely occurs, even on modest slopes. In fact, in all but very intense rainfall occurrences, stormwater runoff from a healthy, relatively dense lawn is at or near zero.
However, some notable exceptions to this include very steep slopes, saturated soil conditions, severely compacted soils and frozen ground. While the total quantity of runoff water is reduced, increased water infiltration also reduces runoff velocity, thereby reducing the amount of sediment carried in runoff.
Not only does increased water infiltration help protect surface water quality, it also helps recharge groundwater supplies. In addition, the dense, fibrous network of roots helps to trap and remove nutrients and other pollutants from water moving down through the soil. This filtering effect can actually improve water quality as it moves through the turfgrass root zone.
Turfgrass and the Soil Environment
The periodic sloughing-off of grass roots, stems and leaves associated with the annual growth cycle of our cool season grasses contributes large amounts of organic matter to the soil over the years. It is a well known fact that soil organic matter additions are among the most important soil-improving practices that can be done. This is not only true for our lawns but our gardens and trees as well. In time, even unimproved, compacted soils over which a lawn has been established will benefit from this natural organic matter addition.
The soil structure improvement and humus development associated with these organic matter additions also contributes to improved water infiltration, greater rooting depth allowing for an expanded root zone with increased access to soil water and nutrient reserves, improved microbial activity and, ultimately -- a healthy, more vigorous, more competitive lawn.
The turfgrass root zone is an area of high soil microorganism activity. Because of this, many of the commonly used turfgrass pesticides, once in contact with the soil, are readily broken down into the basic elements of carbon, oxygen, hydrogen and a small amount of mineral elements such as nitrogen and phosphorous. With this enhanced potential for breaking down soil contaminants such as pesticides, there is less opportunity for these materials to leach through the soil and effect groundwater supplies or be carried off-site in runoff water and affect surface water resources.
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Turfgrass Benefits Related to Temperature Modification  |
The sustainable landscape, including lawns, trees and shrubs, can play an important role in moderating summer air temperatures in our often harsh, urban environments. Trees, shrubs and lawn areas around homes can reduce air temperatures from 7 o to 14o F. through the effects of shading and evapotranspiration2. This can directly result in curbing summer air conditioning costs. One estimate suggests that strategic planting of lawns and other landscape plants could reduce total U.S. air conditioning energy requirements by 25 percent1.
Green lawn areas also provide cooler summer places for children to play than asphalt or concrete surfaces. In addition to their cooling influence, the cushioning effect of a lawn surface can reduce the potential for injuries.
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Other Turfgrass Benefits to the Environment  Healthy lawns and other landscape plantings contribute to improved air quality by acting as traps for dust and other particulate matter. This is especially true in urban areas where dust generated by motorized vehicles can be trapped and washed down into the soil preventing further movement. Nutrients or other contaminants carried on the dust particles may then be used by the plant or broken down and used by soil microorganisms. Because a lawn completely covers a soil surface, soil particles are prevented from blowing around and being carried into the atmosphere where they can be transported and redeposited in another area or region. |
Green plants are termed autotrophs. That is, they are capable of making their own food through the process of photosynthesis. Trees, shrubs, and the individual grass plants that collectively make up our lawns take in carbon dioxide (CO2) and convert it into simple sugars. These can then be further combined into a large array of other needed plant chemical products. As a result of photosynthesis and the taking up of CO2, oxygen (O2) is given off back into the atmosphere. One estimate indicates that during the active growing season, a healthy lawn area of 25 square feet will provide enough O2 for one adult person for one day2. Therefore, our green plants, including lawns, through the process of photosynthesis, contribute to a reduction in atmospheric CO2 while giving back O2.
Lawn areas alone and in combination with other landscape plants contribute to reductions in noise levels by absorbing, deflecting, reflecting, and refracting the various sounds. Likewise, reductions in discomforting glare and light reflection have been noted as a positive benefit of lawn and landscape plantings.
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Turfgrass Benefits Related to the Human Element Landscape plantings, including lawn areas around the home and workplace, have been shown to affect people positively. A healthy, maintained lawn area creates an inviting view for those passing by and provides an aesthetically pleasing , natural backdrop for other landscape elements. Uniformity of the lawn surface helps confer a sense of coherence and harmony to the entire landscape scene. It is this peacefully appearing setting that is believed to contribute to a person's feeling of well being and a decrease in emotional tension. In has also been noted that patient recovery rate is faster where they have a view to a landscaped setting versus a view of adjacent buildings only1. |
The physical and social problems often associated with inner cities can, in part, be related to the absence of lawns and other ornamental landscape plantings. When areas are cleaned up and various landscape plantings reintroduced, there is a noted improvement in the physical environment. There is also an increase in neighborhood people pulling and working together thereby strengthening the various social relationships and overall community bonding.
Creating healthy and sustainable lawns and landscapes that provide these and many other human and environmental benefits does not happen by chance. It begins with a carefully considered, well-planned landscape design. Selecting the most appropriate plant material is important followed by a maintenance program that minimizes resource losses (e.g., nutrients, soil, water) from the ecosystem. In turn, these lawns and landscapes will require fewer outside inputs to sustain their health and remain environmentally functional and aesthetically pleasing.
For more information about the environmental benefits of lawns, see How the Environment Benefits from a Well-Maintained Lawn.
1Hull, R. J., Alm, S. R., and Jackson, N., Toward Sustainable Lawn Turf, in Handbook of Integrated Pest Management for Turf and Ornamentals, Leslie, A.R., Ed., Lewis Publishers, Boca Raton, FL, 1994, chap. 1.
2 Roberts, E. C. and Roberts, B. C., Lawn and Sports Turf Benefits, The Lawn Institute, Pleasant Hill, TN, 1987, 31pp.