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

correlated with human population densities in various watersheds (Peierls et al., 1991; Vitousek et al., 1997). Turfgrass landscapes have the potential for loss of applied N However, the underlying sources of elevated N in waterthrough both runoff and leaching. Lower maintenance alternative vegetation used in mixed-species landscapes may reduce N leaching sheds remain unclear. One possibility includes fertilizer and runoff, which is important for reducing N pollution of surface and N runoff and leaching from residential and commercial ground waters. However, few studies have examined this paradigm. landscapes, where routinely fertilized turfgrass is a maTherefore, we constructed a field-scale facility to compare fertilizer N jor landscape component (Kelling and Peterson, 1975; runoff and leaching between St. Augustinegrass [Stenotaphrum secunPetrovic, 1990). As residential land use increases, the datum (Walt.) Kuntze] and a mixed-species landscape. Four replicapotential for N loss to water resources becomes even tions of each landscape were randomly assigned to 50-m2 plots. A greater. Therefore, a better understanding of N pollumedium-fine sand (75-cm depth) was used as the root zone mix. A tion from residential landscapes is needed. In Florida, blended granular fertilizer was applied at a rate of 300 and 150 kg N where urban populations are rapidly expanding, efforts ha 1 yr 1 on the turfgrass and mixed-species, respectively. Throughout to assess N leaching and runoff from urban landscapes the first year following installation of the landscapes, fertilizer N loss in surface runoff was insignificant. In contrast, N leaching losses were are underway (Erickson et al., 1999). significantly greater on the mixed-species landscape during three ferSt. Augustinegrass is the predominant vegetation used tilizer cycles, resulting in 48.3 kg N ha 1 compared with 4.1 kg N in Florida residential landscapes. It is a moderate fertilha 1 for the St. Augustinegrass annually. The results from the newly ity warm-season turfgrass that receives 150 to 300 kg N established landscapes presented here indicated that St. Augustineha 1 yr 1 when appropriately fertilized (Cisar et al., grass was more efficient at using applied N and minimizing N leaching 1991). No quantitative N leaching and runoff data specifcompared with the alternative landscape. Furthermore, the study idenically from St. Augustinegrass in Florida are available, tified areas of concern with respect to N management practices on although a number of investigators have demonstrated alternative landscapes. These results hold implications for future landconditions favorable for N runoff and leaching from scape models and management of resources in a residential setting. 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 A alterations in the N cycle have been coarse-textured soils (Reike and Ellis, 1974). In addiquite severe with numerous consequences (Aber tion, excessive irrigation may lead to N leaching (Snyder et al., 1995; Vitousek et al., 1997). As a result, various reet al., 1984). However, very little N leaching or runoff search projects have focused on the ecology of humanhas generally been observed from judiciously managed altered N cycling in terrestrial and aquatic ecosystems. turfgrass (Gross et al., 1990; Miltner et al., 1996; Morton Much of the literature indicated an overall decline in et al., 1988; Snyder et al., 1980; Star and DeRoo, 1981). both plant and animal species diversity and accelerated Thus, the literature demonstrates the potential for N eutrophication (Howarth, 1988; National Research Counpollution from various turfgrass landscapes, but the cil Committee on Wastewater Management for Coastal magnitude of N pollution has been highly variable and Areas. Water Science and Technology Board, 1993). In context specific. addition to ecological consequences, greater losses of A University of Florida Extension initiative, entitled NO 3 –N to ground water increase the likelihood of exThe Florida Yards and Neighborhoods (FYN) Program, ceeding the NO 3 –N drinking water standard of 10 mg began in the 1990s in response to numerous residential L 1 set by the EPA for human safety. While sources of landscape concerns, including N pollution (Best, 1994). anthropogenic N pollution are diverse, large human popThe program advocates the use of alternative landscape ulation concentrations have unquestionably impacted materials requiring less water and fertilizer inputs that water resources through N pollution (Cole et al., 1993; might conceivably reduce N pollution from urban areas. Vitousek et al., 1997). For example, increasing NO 3 –N However, while landscapes utilizing the principles of concentrations and fluxes in water resources have been the FYN Program are intended to enhance the environment by reducing harmful N pollution (Garner et al., J.E. Erickson, Forest Ecology and Management, Univ. of Wisconsin, 1996), no data are available to quantify N leaching and 1630 Linden Dr., Madison, WI 53706; J.L. Cisar, Environmental Horticulture, Fort Lauderdale Research and Education Center, 3205 Colrunoff from FYN alternative landscapes. Analogous to lege Ave, Fort Lauderdale, FL 33314; J.C. Volin, Environmental Scithe objectives of the FYN Program, other authors have ences, Florida Atlantic University, 2912 College Ave., Davie, FL proposed the use of alternative plant materials in resi33314; and G.H. Snyder, Soil and Water Science, Everglades Research dential landscapes to minimize environmental impacts, and Education Center, P.O. Box 8003, Belle Glade, FL 33430. Journal Series no. R-08216 of the Florida Agricultural Experiment Station. especially in arid climates where water conservation is Received 15 Dec. 2000. *Corresponding author (jeerick1@students. wisc.edu). Abbreviations: ET, Evapotranspiration; FYN, Florida Yards and Neighborhoods. Published in Crop Sci. 41:1889–1895 (2001).