Turfgrass represents a significant land cover type nationally, and is a dominant vegetation type in urbanized areas. In ecological analyses of urban areas, all turfgrass area is usually treated the same, despite evidence from sod production studies that management (i.e. fertilizing and watering) can alter turfgrass productivity by orders of magnitude, and evidence from surveys that management by homeowners is quite variable. In this study, we present results from an experiment testing the effects of the three most common lawn management practices performed by homeowners. We applied several levels of mowing, irrigation, and fertilization treatments to a two-year-old mix of tall fescues recommended for home lawns, and monitored C and N pools and fluxes for two growing seasons.
Results/Conclusions
This turf system was highly productive (NPP 20-40 Mg/ha) despite a small standing biomass (20-60 Mg/ha). Among treatments, clippings production varied 9-fold, aboveground biomass varied 3-fold, belowground biomass varied 3-fold, soil organic matter (to 10cm) varied by 40%, and soil respiration varied 2-fold. While the C and N content of plant tissues was largely constant, the large variation in biomass pools led to many significant main effects and interactions. We also observed dramatic seasonal variation in pools and fluxes of C and N within each treatment: over the course of a season, clippings production varied as much as 100-fold, aboveground biomass by 50%, belowground biomass by only 3%, soil C by 10%, and soil respiration by 15%. While this is a farm experiment rather than an observational assessment of real-world locations, it seems apparent that turfgrass systems are very dynamic and react strongly to management practices, and this understanding should be incorporated into ongoing work in urban ecology.
