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

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.