Joh-3-59-48 Does St. Augustine grass lose more nitrogen via runoff and leaching than a lower-maintenance mixed-species landscape? Erickson, J. E.* 1,2, J. C. Volin 1, J. L. Cisar 2 and G. H. Snyder 2 Florida Atlantic University, Davie, fl

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Does St. Augustine grass lose more nitrogen via runoff and leaching than a lower-maintenance mixed-species landscape?


Florida Atlantic University, Davie, FL, U.S.A. 1

University of Florida, Fort Lauderdale, FL 33314, U.S.A. 2

Leachate and runoff from residential landscapes on sandy soils may contain substantial levels of nitrogen and other applied nutrients. Therefore, a study was initiated to examine inorganic N losses in leachate and runoff between St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze) and a mixed-species landscape consisting of ground covers, shrubs, and trees. Eight plots, four replications of each treatment, were created at a 10% slope using a medium-fine sand. A granular fertilizer was applied to both landscape treatments. The turfgrass was fertilized at a rate of 300 kg N ha-1 yr-1 and the mixed-species landscape at a rate of 150 kg N ha-1 yr-1. Runoff was collected and analyzed for volume, NH4-N, NO3-N. Overall, runoff volume and nutrient losses were extremely low. Measurable runoff was collected during only one intense rainfall event. No significant difference (p < 0.01) in runoff loss of inorganic N between the treatments was observed. Monthly ET was determined by subtracting the measured leachate from irrigation and precipitation. Following establishment of the mixed-species landscape, no significant differences in ET were observed. Composite daily leachate samples were collected and multiplied by the leachate volume for the respective 24-hour period to give a daily nutrient loading for each plot. Annual leachate N losses were significantly higher on the mixed-species landscape, resulting in 4.83 g N m2 -1 yr-1 compared to 0.23 g N m2 -1yr-1 for the St. Augustine grass. These results reflect the longer establishment period required by the mixed-species landscape.

Keywords: Pollution

Turfgrass (Cynodon dactylon L.) sod production on sandy soils: II. Effects of irrigation and fertiliser regimes on N leaching

Auteur(s) / Author(s)

BARTON L. (1) ; WAN G. G. Y. (1) ; COLMER T. D. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, 6009, Crawley, Western Australia, AUSTRALIE

Résumé / Abstract

The effects of irrigation and fertiliser regimes on N leaching from the production of couch grass (Cynodon dactylon L.) sod, on a free-draining sandy soil, were evaluated in a 22-month field study. The experimental design used a randomised-block, split-plot design with three replicates. Main plots consisted of two irrigation treatments: 70 and 140% daily replacement of pan evaporation; four subplot fertiliser types (water-soluble (predominately NH[4]NO[3]), control-release, pelletised poultry manure and pelletised biosolids); and three N application rates (100, 200 and 300 kg N ha[-1] per crop). Nitrogen leaching was assessed by measuring the leachate volumes and concentrations of N species leached from soil lysimeters (250 mm in diameter by 950 mm in length) installed in 10 m[2] turfgrass plots. Nitrogen leaching ranged from 33 to 167 kg N ha[-1] over 22 months, depending upon the irrigation and fertiliser treatment. Irrigation treatment affected N leaching more than fertiliser treatment, and increasing the irrigation from 70 to 140% replacement of daily pan evaporation increased N leaching for all fertiliser types, and by up to four times. Forty six to 76% of losses occurred from the high irrigation treatments during the first 16 weeks after the turfgrass was planted as rhizomes. By contrast, N leaching did not appear to increase following harvest of sod. At the high irrigation treatment, N leaching was greater for the pelletised biosolids than the control-release; while at the low irrigation treatment, N leaching did not vary between fertiliser types. A significant proportion of the N leached was in the organic form. Therefore, we recommend total N and mineral N be measured when assessing N leaching from turfgrass. Nitrogen leaching from turfgrass production is low from all fertiliser types when the irrigation matches turfgrass water use and N is applied at a rate and frequency that approximates turfgrass requirements.

Revue / Journal Title

Plant and soil  (Plant soil)  ISSN 0032-079X   CODEN PLSOA2 

Source / Source

2006, vol. 284, no1-2, pp. 147-164 [18 page(s) (article)] (29 ref.)

Snow, J.T. 1996. Loss of Nitrogen and Pesticides from Turf via Leaching and Runoff.

accessed 10/29/2007.

Golf and Water Quality.

Accessed 10/29/2007.

Branham, B., E. Milnert and P Rieke. Potential Groundwater Contamination from Pesticides and Fertilizers Used on Golf Courses.

Accessed 10/29/2007.


Adapted from Better Turf Thru Agronomics, Dec. 2002

Sidebar: Key points – Turf Benefits Checklist

What do you do for a living? I grow grass.
"That's the way a Cooperative Extension colleague used to introduce his vocation when he wanted to tell a mixed group about the benefits of turf. Turf researchers, educators, and green industry leaders do need to communicate the benefits of turf in the Southwestern landscape. Our clientele in California continue to make decisions that impact the industry and the citizens of our state. We have factual evidence that turf protects soil and water resources and improves the quality of urban and suburban life," says Vic Gibeault, University of California (UC) Cooperative Extension Environmental Horticulturist and delegate to the UC Riverside Turfgrass Research Advisory Committee (UCRTRAC).

Too often, turf is thought of as an attractive lawn or golf course amenity that guzzles scarce water resources. It's not a valid assessment. Turf reduces runoff and soil erosion, protects groundwater and surface water quality, is linked to decomposition of polluting organic chemicals, dissipates heat, gives cushioning against injuries, and reduces stress, benefiting human health, Gibeault said.

"Turf has a multifaceted story that we need to tell. The scientific research findings in the literature are compelling," Gibeault said. Summarized herein are the benefits of turf to the environment and human health, based on recent reviews and findings in the scientific literature. References are noted at the end of the article.
Soil Erosion Control and Dust Stabilization
Turf protects nonrenewable soil resources from water and wind erosion. Turf's high shoot density and root mass stabilize surface soil, preventing erosion. Mowed turfgrasses are estimated to have shoot densities ranging from 75 million to greater than 20 billion shoots per hectare. During storms, turf's high biomass matrix provides resistance to lateral surface water flow, which slows otherwise potentially erosive water velocities. Quality turfgrass stands modify the overland process of water flow so that runoff is insignificant in all but the most intense rainfall events.

Perennial turfgrasses offer one of the most cost-effective methods to control water and wind erosion of soil, reducing dust and mud problems around homes, schools, factories, and businesses.

Turf can function as vegetative filter strips that greatly reduce the sediment transported into surface streams and rivers, especially when positioned down slope from cropland, mines, and animal production facilities. The reduction in sediment movement not only protects soil resources, but it also reduces sediment-linked nonpoint surface water pollution in rivers, lakes, and streams.

Groundwater Recharge and Surface Water Quality
Turfgrasses preserve water quality primarily by their growth habit, which consists of a huge biomass of short, fine-textured stems and narrow leaves that trap and hold what would otherwise be runoff water. When soil is planted to turf, more water infiltrates and filters through the soil-turfgrass ecosystem, enhancing groundwater recharge, rather than increasing surface runoff.

Results of a research study in Maryland that compared surface water runoff losses from a perennial turf and a cultivated tobacco grown at the same site were noteworthy: During the tobacco-growing season (May - September), surface water runoff losses for the tobacco were 11 times greater than the runoff losses from the perennial turf (6.7 mm ha-1 4 wk-1 for tobacco vs. 0.6 mm ha-1 4 wk-1 for turf). Surface runoff losses for total nitrogen (N) and phosphorus (P) also differed and followed the same pattern. Runoff from the tobacco plantings had 195 times more N and 240 times more P than runoff from the turf. For turf, surface runoff losses of N and P were 0.012 and 0.002 kg ha-1 4 wk-1 , respectively, vs. 2.34 and 0.48 kg ha-1 4 wk-1 losses of N and P, respectively, for tobacco.)

Turfgrass ecosystems support abundant earthworm populations, which contribute to increased macropore space in soil, resulting in higher soil water infiltration rates, higher water-holding capacity, and improved soil structure. The reduction in runoff volume linked to turf can lead to a decrease in stormwater management expenses.

Organic Chemical Decomposition
The turf-soil ecosystem - turf leaves, crowns, stems, roots, thatch, soil, and soil microbes - supports large populations of microscopic "decomposers," beneficial soil microflora (bacteria, actinomycetes, other fungi) and fauna, which are associated with turf and known to break down pesticides and other noxious organic chemicals into harmless substances. Some researchers recommend designing turf areas to serve as catchment, filtration, and "scrubbing" zones for polluted runoff waters from impervious surfaces in urban areas. Research is ongoing to assess the carbon monoxide cleanup potential of turf planted on roadsides.

Soil Improvement and Restoration
Turfgrasses improve soil through organic matter additions derived from the turnover of roots and other plant tissues photosynthesized from atmospheric CO2. Planting perennial turf can accelerate restoration of environmentally damaged soils, such as burned-over land, garbage dumps, eroded rural landscapes, mining operations, and steep timber harvest areas. In time, some of these sites can be developed into recreational areas.

In addition to soil restoration, urban landscapes planted to turf (home lawns, parks, commercial landscapes, recreational facilities, golf courses and other greenbelts) provide an important sink to offset C emissions (increases in atmospheric CO2). Recent research in Colorado assessed the rate of soil C sequestered in turfgrass systems using long-term soil testing data. Nonlinear regression analysis of historic data indicated a strong pattern of soil organic matter response to decades of turfgrass culture. The researchers concluded that C sequestration in turf soils occurs at a significant rate (12 to 15 million t C/yr), which is comparable to that reported for land placed in the USDA's Conservation Reserve Program (13 million t C/yr).

Temperature Moderation
Turfgrasses and other landscape plantings dissipate radiant heat through the cooling process of evapotranspiration, which saves energy by reducing the interior mechanical cooling needed for nearby homes and commercial buildings. The temperature benefit linked to turf is especially important in California, the second-most urbanized state in the U.S., where absolute urban temperatures have been increasing since 1940.

Recreational Benefits
Every day, professional and amateur athletes experience the cushioning that well-maintained turf provides against personal injuries. Turfgrasses can offer a low-cost, safe surface for outdoor leisure activities and recreational sports. Recreation on turf surfaces improves physical and mental health, relieves stress, and contributes to enjoyment of life, all of which are vital to the quality of life in contemporary society.

It is unwise to cut the school maintenance budget (irrigation, fertilization, pest and thatch control) for athletic fields planted to turf because developing athletes are put at significant risk. In a study of football injuries at 12 Pennsylvania high schools, researchers determined that one-fifth were definitely or possibly field-related. Fields with good quality turfgrass cover have higher traction, cushioning, and resiliency, and lower surface hardness, reducing the probability of injury in contact sports.

A smooth, durable, uniform turf surface is important to the play and outcome of a game. Ball roll and bounce are influenced by the turf cover and its management, as are player movements, such as running, cutting, veering, stopping, pivoting, dodging, lunging, jumping, landing, and walking. The overuse of many community sports facilities can push the limits of turf to recover. Certain grasses have been bred to better withstand traffic from cleats.

Aesthetics and Health Benefits
Within urban and suburban areas, it is accepted that parks and attractive landscaping near homes, schools, and businesses increase property values and neighborhood satisfaction. A beautiful green lawn or golf course enhances the quality of life because of its aesthetic appeal, but, in addition, researchers are finding measurable, verifiable health benefits.

Psychologists who study people-plant interactions quantify their results by testing blood pressure and heart rate to document the health benefits of "nearby nature" (turf and mixed landscapes and natural settings). Views of open green space promote quicker recovery from experimentally induced stress when compared to busy mall scenes. Hospital patients matched for age, gender, pre-surgical health, and socioeconomic status who were provided an outdoor view of nature recovered more quickly and required fewer, less potent analgesics than patients whose rooms viewed a hospital wing.

Attention to roadside aesthetics can reduce commuter stress. In laboratory experiments, participants who viewed nature-dominated roadside environments had quicker and more complete recovery from induced stress than participants who viewed artifact-dominated scenes, as measured by heart rate and blood pressure.

Cost-Benefit Analysis
Regarding turf's benefits, Gibeault said, "Cost-benefit analyses will express a truncated view of turf's advantages to the environment and human health unless turf researchers and green industry leaders are effective advocates of turf's multifaceted roles in the landscape. As we educate our clientele about well-maintained turf, they will have a comprehensive view of its multiple, essential benefits to the urban and suburban communities."

Key Points

Turf Benefits Checklist

Soil and Water Resources
• Turf protects groundwater quality and improves recharge.
• Turf reduces surface water runoff and protects surface water quality.
• Turf reduces soil erosion and stabilizes polluting dust.
• The turf-soil ecosystem entraps and biodegrades polluting organic chemicals.
• Turf accelerates restoration of disturbed soils.
• Turf provides flood control.

Other Functional Benefits
• Turf saves energy in urban areas. Turf dissipates heat, reducing energy required to cool nearby homes and commercial buildings.
• Turf abates noise and reduces glare.
• Mowed turf decreases disease-carrying pests (mosquitoes, ticks) and snakes in the landscape.
• Mowed turf produces few, if any, flowers and allergy-linked pollens.
• Well-managed turf can reduce the fire hazard of homes and buildings near canyons, brush, and wooded areas.
• Well-maintained turf and landscaping increase property values.

Recreational Benefits
• Turf provides high-quality cushioning against impact injuries in amateur and professional sports.
• Turf is a low-cost, durable, smooth surface for play and relaxation during outdoor leisure activities.

Aesthetics & Health Benefits
• Well-maintained turf and natural scenery have positive therapeutic effects, as measured by heart rate and blood pressure.
• Green turf enhances landscape attractiveness.

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Beard, J.B. and R. L. Green. 1994. The Role of Turfgrasses in Environmental Protection and Their Benefits to Humans. J. Environ. Qual. 23:452-460.

Gibeault, V. 1995. Turf Benefits I and II. Co-Hort Cooperative Extension Newsletter, Univ. of Calif., Riverside, Winter and Spring, 1995.

Parsons, R., Tassinary, L.G., Ulrich, R.S., Hebl, M.R., and M. Grossman-Alexander. 1998. The View from the Road: Implications for Stress Recovery and Immunization. J. Exp. Psych. 18:113-140.

Qian, V. and R.F. Follett. 2002. Assessing Soil Carbon Sequestratian in Turfgrass Systems Using Long-Term Soil Testing Data. Agron. J. 94:930-935.

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