Greenhouse gas fluxes from turfgrass systems: Species, growth rate, clipping management, and environmental effects.

Abstract

Turfgrass systems can be an important source or sink for greenhouse gases (GHG), including carbon dioxide (CO2 ), nitrous oxide (N2 O), and methane (CH4 ). Further research is required in turfgrass systems; therefore, our objectives were to evaluate the effects of turfgrass species, growth rate, clipping management, and environmental conditions on GHG emissions. Greenhouse gas fluxes were measured in two separate field experiments in West Lafayette, IN. Experiment 1 investigated GHG flux in three cool-season (C3 ) and two warm-season (C4 ) turfgrass species during two growing seasons. Experiment 2 investigated fluxes in two C3 cultivars with varying growth rates and under different clipping management regimes. The C3 turfgrasses had the highest mean CO2 flux rates ranging from 0.373 to 0.431g CO2 -C m-2 h-1 compared with 0.273 to 0.361g CO2 -C m-2 h-1 for C4 turfgrasses. Mean hourly N2 O flux rates ranged from 43.3 to 50.9μg N2 O-N m-2 h-1 for C3 compared with 11.1 to 14.4μg N2 O-N m-2 h-1 for C4 turfgrasses. Methane flux was more variable across time, but overall C4 turfgrasses were more likely to be a CH4 source, whereas C3 turfgrasses were often a CH4 sink. Growth rate and grass clipping management treatments had negligible impact on measured GHG flux. The differences in management practices specific to C3 and C4 turfgrasses had the largest impact on GHG flux. Results indicate the impact and importance of turfgrass species selection on GHG flux and also provide more information on our overall understanding on carbon and nitrogen cycling in urban soils.