HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Erickson, J. E. Articles by Snyder, G. H. Search for Related Content PubMed Articles by Erickson, J. E. Articles by Snyder, G. H. Agricola Articles by Erickson, J. E. Articles by Snyder, G. H. Related Collections Vadose Zone Processes and Chemical Transport Crop Ecology Turfgrass

TURFGRASS SCIENCE

Comparing Nitrogen Runoff and Leaching between Newly Established St. Augustinegrass Turf and an Alternative Residential Landscape

^a Forest Ecology and Management, Univ. of Wisconsin, 1630 Linden Dr., Madison, WI 53706
^b Environmental Horticulture, Fort Lauderdale Research and Education Center, 3205 College Ave, Fort Lauderdale, FL 33314
^c Environmental Sciences, Florida Atlantic University, 2912 College Ave., Davie, FL 33314
^d Soil and Water Science, Everglades Research and Education Center, P.O. Box 8003, Belle Glade, FL 33430

* Corresponding author (jeerick1{at}students.wisc.edu)

	ABSTRACT

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Turfgrass landscapes have the potential for loss of applied N through both runoff and leaching. Lower maintenance alternative vegetation used in mixed-species landscapes may reduce N leaching and runoff, which is important for reducing N pollution of surface and ground waters. However, few studies have examined this paradigm. Therefore, we constructed a field-scale facility to compare fertilizer N runoff and leaching between St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] and a mixed-species landscape. Four replications of each landscape were randomly assigned to 50-m² plots. A medium-fine sand (75-cm depth) was used as the root zone mix. A blended granular fertilizer was applied at a rate of 300 and 150 kg N ha^-1 yr^-1 on the turfgrass and mixed-species, respectively. Throughout the first year following installation of the landscapes, fertilizer N loss in surface runoff was insignificant. In contrast, N leaching losses were significantly greater on the mixed-species landscape during three fertilizer cycles, resulting in 48.3 kg N ha^-1 compared with 4.1 kg N ha^-1 for the St. Augustinegrass annually. The results from the newly established landscapes presented here indicated that St. Augustinegrass was more efficient at using applied N and minimizing N leaching compared with the alternative landscape. Furthermore, the study identified areas of concern with respect to N management practices on alternative landscapes. These results hold implications for future landscape models and management of resources in a residential setting.

Abbreviations: ET, Evapotranspiration • FYN, Florida Yards and Neighborhoods

	INTRODUCTION

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
ANTHROPOGENIC ALTERATIONS in the N cycle have been quite severe with numerous consequences (Aber et al., 1995; Vitousek et al., 1997). As a result, various research projects have focused on the ecology of human-altered N cycling in terrestrial and aquatic ecosystems. Much of the literature indicated an overall decline in both plant and animal species diversity and accelerated eutrophication (Howarth, 1988; National Research Council Committee on Wastewater Management for Coastal Areas. Water Science and Technology Board, 1993). In addition to ecological consequences, greater losses of NO^-₃–N to ground water increase the likelihood of exceeding the NO^-₃–N drinking water standard of 10 mg L^-1 set by the EPA for human safety. While sources of anthropogenic N pollution are diverse, large human population concentrations have unquestionably impacted water resources through N pollution (Cole et al., 1993; Vitousek et al., 1997). For example, increasing NO^-₃–N concentrations and fluxes in water resources have been correlated with human population densities in various watersheds (Peierls et al., 1991; Vitousek et al., 1997). However, the underlying sources of elevated N in watersheds remain unclear. One possibility includes fertilizer N runoff and leaching from residential and commercial landscapes, where routinely fertilized turfgrass is a major landscape component (Kelling and Peterson, 1975; Petrovic, 1990). As residential land use increases, the potential for N loss to water resources becomes even greater. Therefore, a better understanding of N pollution from residential landscapes is needed. In Florida, where urban populations are rapidly expanding, efforts to assess N leaching and runoff from urban landscapes are underway (Erickson et al., 1999).

St. Augustinegrass is the predominant vegetation used in Florida residential landscapes. It is a moderate fertility warm-season turfgrass that receives 150 to 300 kg N ha^-1 yr^-1 when appropriately fertilized (Cisar et al., 1991). No quantitative N leaching and runoff data specifically from St. Augustinegrass in Florida are available, although a number of investigators have demonstrated conditions favorable for N runoff and leaching from turfgrass land use (Kelling and Peterson, 1975; Petrovic, 1990; Snyder et al., 1984). For example, the potential for N leaching from turfgrass may be substantial on coarse-textured soils (Reike and Ellis, 1974). In addition, excessive irrigation may lead to N leaching (Snyder et al., 1984). However, very little N leaching or runoff has generally been observed from judiciously managed turfgrass (Gross et al., 1990; Miltner et al., 1996; Morton et al., 1988; Snyder et al., 1980; Star and DeRoo, 1981). Thus, the literature demonstrates the potential for N pollution from various turfgrass landscapes, but the magnitude of N pollution has been highly variable and context specific.

A University of Florida Extension initiative, entitled The Florida Yards and Neighborhoods (FYN) Program, began in the 1990s in response to numerous residential landscape concerns, including N pollution (Best, 1994). The program advocates the use of alternative landscape materials requiring less water and fertilizer inputs that might conceivably reduce N pollution from urban areas. However, while landscapes utilizing the principles of the FYN Program are intended to enhance the environment by reducing harmful N pollution (Garner et al., 1996), no data are available to quantify N leaching and runoff from FYN alternative landscapes. Analogous to the objectives of the FYN Program, other authors have proposed the use of alternative plant materials in residential landscapes to minimize environmental impacts, especially in arid climates where water conservation is a major concern (Hipp et al., 1993; Sacamano and Jones, 1975). In fact, a study considering alternative landscapes on silty clay in Texas observed more runoff from a high maintenance landscape, which was attributed to antecedent soil moisture. However, the results were somewhat inconclusive with respect to N pollution since N leaching was not measured (Hipp et al., 1993). Overall, very little is known about N pollution from alternative landscapes.

Due to the lack of data regarding N pollution from residential landscapes, there is considerable interest in quantifying the magnitude of N runoff and leaching from these contrasting residential landscape types. Therefore, we constructed a field-scale facility to monitor N pollution from contrasting residential landscapes at the lawn scale level for three approximately 4-mo fertilizer cycles (Erickson et al., 1999). The objective of this study was to compare N leaching and runoff between a St. Augustinegrass monoculture and a mixed-species landscape designed by the FYN Program. In pursuing this objective, we tested the null hypothesis that no difference in N leaching and runoff would be observed between the two contrasting landscape systems.

	MATERIALS AND METHODS

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
A facility containing eight 9.5 by 5.0 m research plots was constructed at the University of Florida's Fort Lauderdale Research and Education Center to collect both surface runoff and subsurface percolate from two contrasting landscape treatments. One treatment consisted of a ‘Floratam’ St. Augustinegrass monoculture and the other treatment was an arrangement of ornamental ground covers, shrubs, and trees designed by Mr. Allen Garner of the FYN program. The St. Augustinegrass was installed as a sod and maintained at a height of 7.5 cm. The clippings were removed for the first 6 mo of the study and mulched in situ for the final 6 mo. The mixed-species landscape consisted of 12 ornamental species and contained no turfgrass (Table 1). Over 50% of the species used were considered native to Florida. All species were commercially available and purchased at a local nursery. The plants were installed from pots with the soil and intact root systems. Following the protocol of the FYN program, eucalyptus mulch (The Bushel Stop, Pompano Beach, FL) was uniformly applied at a depth of 7.5 cm on the mixed-species landscape to minimize soil water evaporation and weed growth.

In each of the eight plots we installed a rectangular perimeter irrigation system comprised of six inward-facing spray nozzles. The rate of irrigation was uniform across all plots (Erickson et al., 1999). After about 5 mo, the irrigation on the ornamental plots was converted to a microjet irrigation system, which delivered water directly to the plants. An irrigation time clock controlled each plot as a separate zone. An automatic rain shutoff switch was connected to the time clock to avoid irrigation following sufficient rainfall. Irrigation volume applied to each treatment was recorded based on a flow meter installed in the irrigation system. Soil percolate was measured initially by random manual measurements on each plot and subsequently by tipping bucket flow gauges (Unidata America-Model 6406H, Lake Oswego, OR) that continuously monitored percolate volume. A data logger (CR10X, Campbell Scientific, Logan, UT) recorded the percolate volume. Rainfall was recorded continually and averaged monthly. Both rainfall and irrigation were randomly tested for inorganic N (NO^-₃–N and NH⁺₄–N). Estimates of evapotranspiration (ET) were calculated using a moisture budget system based on the following formula: ET = irrigation + rainfall - percolate (Snyder et al., 1980).

For each of the approximately 4-mo cycles, fertilizer N was applied at a rate of 50 kg N ha^-1 per application to both treatments. However, the fertilizer was applied twice per cycle to the St. Augustinegrass (300 kg N ha^-1 yr^-1) and only once per cycle to the mixed-species (150 kg N ha^-1 yr^-1). Thus, each cycle was determined by the fertilization dates on the mixed-species landscape. The fertilization programs used in the study were moderate for both landscapes and common for subtropical conditions in south Florida (Cisar et al., 1991; Yeager and Gilman, 1991). A blended 26-3-11 (N-P₂O₅-K₂O) granular fertilizer (LESCO Inc., Sebring, FL) was chosen for both treatments, except for the last cycle when a 12-2-14 (N-P₂O₅-K₂O) mix was used on the mixed-species landscape to supply more K and micronutrients to the ornamental species. According to the Florida label on the fertilizer bag, N sources in the fertilizer were urea (58%), S-coated urea (37.5%), and ammonium phosphate (4.5%). The granular material was hand distributed and watered in with approximately 5.0 mm of irrigation at each application.

Planting of both treatments occurred on 18 Dec. 1998. The first fertilizer cycle and data collection commenced in February 1999. Nitrogen leaching and runoff data were collected continually for all three cycles over a 12-mo period following the onset of fertilization. A gutter system at the base of each plot was designed to collect any surface water runoff during storm events. Initially, percolate flow measurements and samples were taken at least once daily from a slotted drainage pipe placed across the lower edge of each plot, which drained the percolate for the entire plot. Beginning in July, ISCO (model 2900) Autosamplers (ISCO, Inc., Lincoln, NE) were installed to collect daily composite percolate samples. The automated samplers were programmed to draw a fresh 50-mL percolate sample from the tipping bucket every 6 h to an internal sample container. Thus, a daily (24 h) 200-mL composite sample was collected and used for subsequent N analyses. Both runoff and percolate water samples were immediately acidified with sulfuric acid upon collection and refrigerated at 4°C until analysis. The samples were analyzed for inorganic N (NH⁺₄–N and NO^-₃–N) using colorimetric autoanalyzers (OI Analytical, College Station, TX; U.S. EPA Methods 350.1 and 353.2). All analyses were performed at the University of Florida Analytical Research Laboratory (ARL) in Gainesville, FL.

The experimental design for this study was a completely randomized design with a single factor, landscape type. The design included two treatments and four replications per treatment. Inorganic N loadings (quantity leached) in runoff and percolate were calculated from each replication. For runoff samples, the concentration of nutrient was multiplied by volume of the runoff event. In the percolate samples, a daily nutrient load was determined by multiplying the concentration of each nutrient found in the daily composite percolate sample by the volume of percolate measured for the respective 24-h period. Statistically significant treatment effects on inorganic N loading in runoff and percolate for each approximately 4-mo fertilizer cycle were identified using SAS analysis of variance procedures (SAS Institute, 1989).

	RESULTS

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Hydrology
The hydrology in southern Florida involves a wet season (June–November), when rainfall is abundant, and a dry season (December–May), in which relatively little rainfall is received (Fig. 1) . During the first cycle, which was entirely in the dry season, only 195 mm of rainfall was received. In contrast, approximately 1160 mm was received during the second cycle in the wet season. The third cycle encompassed both seasons and accordingly 700 mm of rainfall was measured. Almost 90% (1838 mm) of the total rainfall was in the wet season, with only 216 mm in the dry season. Two particularly intense storm events brought an excess of 250 mm per event, illustrating the potential for substantial precipitation in subtropical southern Florida. The mean concentration of inorganic N measured in the rain was 1.23 mg L^-1 (n = 4). Thus, based on this mean N concentration and 2054 mm of rainfall, 25.3 kg N ha^-1 were received during the year via wet deposition. In addition to rainfall, supplemental irrigation was applied to both treatments (Fig. 1). The mean concentrations of NO^-₃–N and NH⁺₄–N in the irrigation were <0.2 and 1.0 mg L^-1, respectively (n = 6). The St. Augustinegrass received 9% more irrigation than the mixed-species throughout the study (951 and 872 mm of irrigation were applied to the turf and the mixed-species, respectively). Both landscapes were planted in the dry season; therefore more than one-half of the supplemental irrigation was applied to the grass (507 mm) and the mixed-species (474 mm) during the first cycle. The relative annual savings in irrigation on the mixed-species will probably be even greater than what we observed under fully established conditions.

View larger version (22K): [in this window] [in a new window]   Fig. 1. Rainfall and irrigation inputs (mm mo-1). Irrigation was measured by a flow meter in the main irrigation line. Approximately 9% more irrigation was applied to the St. Augustinegrass plots.

View larger version (26K): [in this window] [in a new window]   Fig. 2. Mean daily movement of percolate water (mm d-1) over time (n = 4). Dotted vertical lines represent data cycles corresponding with fertilization dates on the mixed-species landscape. The effect of rainfall on percolate volume can be seen during the wet season with little variation between the treatments following the first cycle.

Even though no significant N runoff was measured on the sandy soil, N losses were observed in the percolate. Significantly greater N (NO^-₃–N + NH⁺₄–N) leaching was observed on the mixed-species landscape in each of the three cycles (Table 2). During the study period, the mixed-species landscape leached 10 times more N than the St. Augustinegrass. Although a fertilizer with approximately 40% slow release N was used, the majority of the fertilizer N leached from the mixed-species landscape each cycle occurred shortly after fertilization (Fig. 3) . The quantity of inorganic N leached from the mixed-species treatment was quite substantial in Cycle 1 in spite of moderate percolate volume. While similar quantities of N were leached in subsequent cycles, intense rainfall (percolate) events occurred following fertilization in Cycles 2 and 3 (Fig. 2). The effect of a severe rainfall event on the mixed-species treatment was evident during the third cycle, where approximately 75% of the N loss for the cycle was related to one storm event (Table 2). In contrast, despite routine fertilization and frequently intense rainfall events, mean N quantities leached from the St. Augustinegrass exhibited relatively little variability and remained consistently low. Still, there was some indication that inorganic N losses in the percolate were slightly higher following fertilization on the St. Augustinegrass (Fig. 3). This slight increase in N loss from the turf following fertilization was in the NH⁺₄–N form with no evident increase in NO^-₃–N loss (data not shown). Overall, the majority of the N leached from the St. Augustinegrass was ammoniacal in nature (87%), while NO^-₃–N was predominant (83%) in the mixed-species percolate. Accordingly, NO^-₃–N concentrations were generally higher in the mixed-species percolate with peaks following fertilization events. The mean NO^-₃–N concentrations in the mixed-species percolate ranged from <0.2 to 15.2 mg L^-1 with an overall mean concentration of 1.46 mg L^-1. In contrast, mean NO^-₃–N concentrations in the St. Augustinegrass percolate never exceeded 0.4 mg L^-1, resulting in an overall mean concentration <0.2 mg L^-1.

View larger version (33K): [in this window] [in a new window]   Fig. 3. Mean daily inorganic N leached (kg ha-1) over time (n = 4). Dotted vertical lines represent fertilization events for both treatments while solid vertical lines represent additional St. Augustinegrass fertilizations. Increases in N leaching following fertilization were generally seen on both treatments, but to a lesser magnitude on the St. Augustinegrass.

	DISCUSSION

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

Nitrogen losses from surface runoff were insignificant from both landscape types even with a 10% slope and frequently intense rainfall. This provided valuable information regarding the surface runoff of nutrients from sandy soils in a subtropical climate. These results corroborate previous research conducted under temperate environmental conditions in which minimal surface runoff from cool-season turfgrasses was observed (Gross et al., 1990; Morton et al., 1988).

While surface runoff was insignificant from either treatment, more than 30% of applied fertilizer N was leached from the mixed-species. In contrast, very little N (<2%) leached from the St. Augustinegrass. The large differences in N leaching between the landscape treatments were seen in all three cycles across varying environmental conditions. Thus, it appears that the applied N behaved quite differently between the treatments during the first year of this study. Atmospheric N loss was not measured, so it is possible that atmospheric loss was greater from the turfgrass treatment, accounting for the differences observed. However, it seems more likely that the differences were in soil–thatch storage and plant uptake because management practices were used that have been shown to minimize gaseous loss, such as irrigation following fertilizer application and a 40% slow release fertilizer source (Bowman et al., 1987; Kelling and Peterson, 1975; Petrovic, 1990). Turfgrasses respond rapidly to applied N and are relatively efficient at N uptake (Cixar et al., 1985; Star and DeRoo, 1981). We speculate that the St. Augustinegrass sod system was more efficient than the mixed-species landscape at retrieving applied N during the study period, due in part to the complete vegetative cover of the grass and dense rapid adventitious rooting into the substrate. The mixed-species plant materials were well rooted at planting, but the density of the plantings was less than the turfgrass as the ornamental landscape was designed for growth with time.

In addition to reduced vegetation density, the results reflected a longer establishing period required by the mixed-species landscape. For example, significantly greater percolate volume and reduced ET (similar dry season conditions) were seen on the mixed-species treatment immediately following planting (Cycle 1) relative to the end of the study. Furthermore, NO^-₃–N concentrations in the percolate were substantially elevated for several weeks following the initial fertilization on the mixed-species landscape.

Nutrient losses were most severe during the first cycle, however, significantly greater N losses on the mixed-species occurred throughout the study. Large pulses of leached inorganic N were observed on the mixed-species treatment following each fertilization event. This postfertilization pulse in N leaching occurred to a much lesser degree on the turfgrass, again suggesting differences in vegetative uptake or soil storage (Fig. 3). Still, the quantities of N leached from the mixed-species treatment probably could be reduced. Inorganic N losses in the percolate have been related to N source and rate, precipitation and irrigation, vegetation, soil properties, and timing of fertilization (Petrovic, 1990). Growth and vigor of St. Augustinegrass with respect to N has been well studied (Cisar et al., 1991). However, clear management practices for maintaining the mixed-species landscape as a whole were not well developed because of the complexity (e.g., palms, woody shrubs, and herbaceous species) of the landscape and the relative infancy of the FYN program. While it is possible that too much fertilizer was applied to the mixed-species landscape, visible signs of nutrient stress, such as stunted growth and chlorotic leaves were seen on several of the species, most notably the liriope [Liriope muscari (Dcne.) Bailey], firebush (Hamelia patens Jacq.), and thyrallis (Galphimia glauca Cav.). Therefore, a reduction in the rate of fertilizer and more frequent applications might reduce the N leaching we observed while increasing plant vigor. Another possibility would be to consider organic soil amendments that release N much slower than the fertilizer blend used in this study.

In this study, we tested the hypothesis that fertilizer N runoff and leaching would be statistically equal between the two newly established contrasting landscape types. The results of the study showed that St. Augustinegrass was efficient at retrieving applied N and minimizing N leaching, despite relatively high fertilizer N requirements. In contrast, significantly greater N losses in the percolate were observed from the alternative mixed-species landscape during first-year establishing conditions. Therefore, we rejected the hypothesis that there would be no difference in N pollution between the two contrasting landscape types. In summary, the data indicated that adverse environmental impacts associated with N pollution are minimal from properly established St. Augustinegrass landscapes. In addition, while alternative landscapes may currently offer other environmental benefits such as wildlife habitat, further research on plant selection and fertilizer management practices for the landscape at a lawn scale are needed to minimize their environmental impact via N leaching during establishing conditions. Finally, continued monitoring of both landscapes through time is needed and will provide valuable data regarding N runoff and leaching from well-established landscapes.

	ACKNOWLEDGMENTS

 
We thank Karen Williams, Kevin Wise, and Scott Park for technical support in the field and David Rich for laboratory assistance. The authors would also like to acknowledge the anonymous reviewers for their comments. This work was supported by the Florida Department of Environmental Protection, Sarasota Bay National Estuary Program, and the University of Florida Agricultural Experiment Station.

	NOTES

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Journal Series no. R-08216 of the Florida Agricultural Experiment Station.

Received for publication December 15, 2000.

	REFERENCES

TOP NOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 

• Aber, J.D., A. Magill, S.G. McNulty, R.D. Boone, K.J. Nadelhoffer, M. Downs, and R. Hallet. 1995. Forest biogeochemistry and primary production altered by nitrogen saturation. Water Air Soil Pollut. 85:1665–1670.
• Best, C.H. 1994. Florida Yards and Neighborhoods Program. Proc. Fla. State Hort. Soc. 107:368–370.
• Bowman, D.C., J.L. Paul, W.B. Davis, and S.H. Nelson. 1987. Reducing ammonia volatilization from Kentucky bluegrass turf by irrigation. HortScience 22: 84–87.[ISI]
• Cisar, J.L., R.J. Hull, D.T. Duff, and A.J. Gold. 1985. Turfgrass nutrient use efficiency. p. 115. In Agronomy Abstracts. ASA, CSSA, and SSSA, Madison, WI.
• Cisar, J.L., G.H. Snyder, and P. Nkedi-Kizza. 1991. Maintaining quality turfgrass with minimal nitrogen leaching. Univ. of Fla., Inst. of Food and Agr. Sci. Bul. 273. Univ. of Florida, Gainesville, FL.
• Cole, J.J., B.L. Peierls, N.F. Caraco, and M.L. Pace. 1993. Nitrogen loadings of rivers as a human-driven process. p. 141–157. In M.J. McDonnell and S.T.A. Pickett (ed.) Humans as components of ecosystems: The ecology of subtle human effects and populated areas. Springer-Verlag, New York, NY.
• Erickson, J.E., J.C. Volin, J.L. Cisar, and G.H. Snyder. 1999. A facility for documenting the effect of urban landscape type on fertilizer nitrogen runoff. Proc. Fla. State Hort. Soc. 112:266–269.
• Garner, A., J. Stevely, H. Smith, M. Hoppe, T. Floyd, and P. Hinchcliff. 1996. A guide to environmentally friendly landscaping—Florida Yards and Neighborhoods Handbook. Univ. of Florida Institute of Food and Agr. Sci. Bull. 295. Univ. of Florida, Gainesville, FL.
• Geron, C.A., T.K. Danneberger, S.J. Traina, T.J. Logan, and J.R. Street. 1993. The effects of establishment methods and fertilization practices on nitrate leaching from turfgrass. J. Environ. Qual. 22: 119–125.[Abstract/Free Full Text]
• Gross, C.M., J.S. Angle, and M.S. Welterlen. 1990. Nutrient and sediment losses from turfgrass. J. Environ. Qual. 19:663–668.[Abstract/Free Full Text]
• Hipp, B., S. Alexander, and T. Knowles. 1993. Use of resource efficient plants to reduce nitrogen, phosphorus, and pesticide runoff in residential and commercial landscapes. Water Sci. Tech. 28(3–5):205–213.
• Howarth, R.W. 1988. Nutrient limitation of net primary production in marine ecosystems. Annu. Rev. Ecol. Systematics 19:89–110.[ISI]
• Kelling, K.A., and A.E. Peterson. 1975. Urban lawn infiltration rates and fertilizer runoff losses under simulated rainfall. Soil. Sci. Soc. Am. Proc. 39:348–352.
• Miltner, E.D., B.E. Branham, E.A. Paul, and P.E. Rieke. 1996. Leaching and mass balance of ¹⁵N-labeled urea applied to a Kentucky bluegrass turf. Crop Sci. 36:1427–1433.[Abstract/Free Full Text]
• Morton, T.G., A.J. Gold, and W.M. Sullivan. 1988. Influence of overwatering and fertilization on nitrogen losses from home lawns. J. Environ. Qual. 17:124–130.[Abstract/Free Full Text]
• National Research Council Committee on Wastewater Management for Coastal Urban Areas. Water Science and Technology Board. 1993. Managing wastewater in coastal urban areas. National Research Council, Washington, DC.
• Peierls, B., N. Caraco, M. Pace, and J.J. Cole. 1991. Human influence on river nitrogen. Nature 350:386–387.
• Petrovic, A.M. 1990. The fate of nitrogenous fertilizers applied to turfgrass. J. Environ. Qual. 19:1–14.
• Reike, P.E., and B.G. Ellis. 1974. Effects of nitrogen fertilization on nitrate movement under turfgrass. p. 120–130. In E.C. Roberts (ed.) Proc. 2nd Int. Turfgrass Res. Conf. Blacksburg, VA. ASA and CSSA, Madison, WI.
• Sacamano, C.M., and W.D. Jones. 1975. Native trees and shrubs for landscape use in the desert southwest. Univ. Arizona Coop. Ext. Serv. Bull. A-82. Univ. of Arizona, Tucson, AZ.
• SAS Institute. 1989. SAS/STAT user's guide. Ver. 6. 4th ed. SAS Inst., Cary, NC.
• Snyder, G.H., E.O. Burt, and J.M. Davidson. 1980. Nitrogen leaching in Bermudagrass turf: 2. Effect of nitrogen sources and rates. p. 313–324 In R.W. Sheard (ed.) Proc. 4th Int. Turfgrass Res. Conf. Guelph, ON, Canada.
• Snyder, G.H., B.J. Augustin, and J.M. Davidson. 1984. Moisture sensor-controlled irrigation for reducing N leaching in Bermudagrass turf. Agron. J. 76:964–969.[Abstract/Free Full Text]
• Starr, J.L., and H.C. DeRoo. 1981. The fate of nitrogen fertilizer applied to turfgrass. Crop Sci. 21:531–536.[Abstract/Free Full Text]
• Vitousek, P.M., J.D. Aber, R.W. Howarth, G.E. Likens, P.A. Matson, D.W. Schindler, W.H. Schlesinger, and D.G. Tilman. 1997. Human alteration of the global nitrogen cycle: Sources and consequences. Ecol. Appl. 7:737–750.
• Yeager, T.H., and E.F. Gilman. 1991. Fertilization recommendations for trees and shrubs in home and commercial landscapes. Univ. of Fla. Coop. Ext. Serv., Circ. 948. Univ. of Florida, Gainesville, FL.

This article has been cited by other articles:

				J. E. Erickson, J. L. Cisar, G.H. Snyder, D. M. Park, and K. E. Williams Does a Mixed-Species Landscape Reduce Inorganic-Nitrogen Leaching Compared to a Conventional St. Augustinegrass Lawn? Crop Sci., July 1, 2008; 48(4): 1586 - 1594. [Abstract] [Full Text] [PDF]

				K. Steinke, J. C. Stier, W. R. Kussow, and A. Thompson Prairie and Turf Buffer Strips for Controlling Runoff from Paved Surfaces J. Environ. Qual., January 25, 2007; 36(2): 426 - 439. [Abstract] [Full Text] [PDF]

				J. E. Erickson, J. L. Cisar, G. H. Snyder, and J. C. Volin Phosphorus and Potassium Leaching under Contrasting Residential Landscape Models Established on a Sandy Soil Crop Sci., January 31, 2005; 45(2): 546 - 552. [Abstract] [Full Text] [PDF]

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Erickson, J. E. Articles by Snyder, G. H. Search for Related Content PubMed Articles by Erickson, J. E. Articles by Snyder, G. H. Agricola Articles by Erickson, J. E. Articles by Snyder, G. H. Related Collections Vadose Zone Processes and Chemical Transport Crop Ecology Turfgrass