Gases and Grasses: Sampling nitrous oxide emissions from urban and suburban lawns

摘要

The vibrancy of a lawn is tied closely to a home's perceived appearance and value, leading many homeowners to apply quantities of nitrogen (N) fertilizer to their lawns. Application of N fertilizer to agricultural soils has been shown to release nitrous oxide (N_2O), a powerful greenhouse gas (GHG) with a 100 year global wanning potential (GWP) of ～300 that can also cause depletion of stratospheric ozone. N_2O emissions from urban and suburban lawns have been measured in only a few places. Such measurements are needed to create regional GHG inventories. A method was developed to sample the soil flux of N_2O from lawns and determine quantitatively the effect of fertilization on N_2O emissions. Sampling was accomplished using closed chambers constructed of 8-inch SCH 40 PVC, deployed for 30 minutes with soil moisture and temperature monitored using time-domain reflectrometry and thermistors, respectively. N_2O concentrations were measured using a gas chromatograph with an electron capture detector. This sampling method proved useful in quantification of N_2O emissions from urban and suburban lawns.