Methane Emissions from a Colorado Golf Course: Effects of Soil Drainage.

Methane is a potent greenhouse gas, and soils act as important sinks to offset atmospheric concentrations. However, anthropogenic land use change interrupts soil processes that alters the soil potential to oxidize methane oxidation potentials. Due to expanding areas and often intensive management of turfgrass, these urban areas are becoming an increasingly important avenue of greenhouse gas investigations to regional budgets. We quantified soil methane flux using the vented chamber method and gas samples were analyzed by gas chromatography. In 2011a study site was established to an adjacent fairway, rough, and restored native site; upon soil analysis and observed annual WFPS this location was observed to have poorly-drained soils. In 2011, emissions from poorly-drained fairway, rough, and native field soils were 0.55, 0.36, and 0.31 kg CH4-C ha-1 yr-1, respectively. In order to evaluate drainage effects from golf course turf, a second field location was chosen in 2012 that was observed to be a well-drained soil. In 2012, CH4 emissions from poorly-drained soils increased to 0.58, 0.76, and 0.40 kg CH4-C ha-1 yr-1. Soil WFPS at poorly-drained sites often exceeded 60%, with soil compaction and irrigation water applications severally inhibiting soil methane oxidation. Emissions from well-drained fairway and rough during 2012 totaled 0.38 and 0.01 kg CH4-C ha-1 yr-1, respectively, and the well-drained native site had net consumption that totaled 0.14 kg CH4-C ha-1 yr-1. While irrigation water was applied at equal amounts, greater soil drainage potentials at the well-drained sites reduced emissions and increased soil methane consumption. Yet in general soil oxidation potentials were retarded from golf course turfgrass, indicating greater implications from highly managed turfgrass on soil methane fluxes than what has been previously considered.