Carbon dioxide and methane emissions by urban turfgrasses under different nitrogen rates: A comparison between tall fescue (Festuca arundinacea schreb.) and hybrid bermudagrass (Cynodon dactylon [l.] pers. var. dactylon x cynodon transvaalensis burtt-davy)

Turfgrass is a major vegetation type in urban and peri-urban areas. Being high maintenance ecosystems, turfs can contribute substantially to urban climate change. The object of this study was to evaluate the contribution to GHG emissions by urban turfgrasses in Mediterranean conditions (Tuscany, central Italy). CO2 and CH4 emission fluxes from a mature stand of tall fescue and bermudagrass were evaluated, by static chambers method, for the assessment of C emission under different nitrogen fertilization rates (0-50-150 kg N ha-1). Both species showed a correlation between N fertilization rate and CO2 emissions, whilst, no correlation was observed for CH4. In the case of tall fescue, cumulative CO2 emissions were significantly higher with 150 kg N ha-1 and no differences were observed between 0 and 50 kg N ha-1. As for bermudagrass differences were found between control and other treatments but no differences were observed on cumulative CO2 emissions between 50 and 150 kg N ha-1. In both species, N fertilization did not affect CH4 emissions. Results indicate that both N rate and turfgrass species influence C emissions, for this reason they should be considered in the management of green areas in the climatic transition zone.