Seasonal N Losses from St. Augustinegrass Lawn Turf: Fertility and Irrigation Interactions.

Recent droughts and conservation irrigation practices have demonstrated that low density, desiccated lawns are becoming more commonplace and potentially more accepted across Texas landscapes.  This shift could represent a significant alteration to urban ecosystem nutrient cycling.  Such changes have not been evaluated for their impact on nutrient loading into surface waters.  Thus, a field study was initiated at the Texas A&M Turfgrass Field Laboratory in College Station, TX, to measure runoff volumes and nutrient loading from St. Augustinegrass (Stenotaphrum secundatum (Walter) Kuntze) lawn turf maintained at varying levels of irrigation and fertility.  Fertilizer applications represented minor contributions to ‘in-season’ N loading.  Late winter decomposition of dormant turf appears to supply a significant portion of annual mineral N loading.