Soil greenhouse gas emissions from Australian sports fields

Managed turf is a potential net source of greenhouse gas (GHG) emissions. While most studies to date have focused on non-sports turf, sports turf may pose an even greater risk of high GHG emissions due to the generally more intensive fertiliser, irrigation and mowing regimes. This study used manual and automated chambers to measure nitrous oxide (N₂O) and methane (CH₄) emissions from three sports fields and an area of non-sports turf in southern Australia. Over 213 days (autumn to late spring), the average daily N₂O emission was 37.6 g N ha^-1day^-1 at a sports field monitored at least weekly and cumulative N₂O emission was 2.5 times higher than the adjacent non-sports turf. Less frequent seasonal sampling at two other sports fields showed average N₂O daily emission ranging from 26 to 90 g N ha^-1 day^-1. Management practices associated with periods of relatively high N₂O emissions were surface renovation and herbicide application. CH₄ emissions at all of the sports fields were generally negligible with the exception of brief periods when soil was waterlogged following heavy rainfall where emissions of up to 1.3 kg C ha^-1 day^-1 were recorded. Controlled release and nitrification inhibitor containing fertilisers didn't reduce N₂O, CH₄ or CO₂ emissions relative to urea in a short term experiment. The N₂O emissions from the sports fields, and even the lower emissions from the non-sports turf, were relatively high compared to other land uses in Australia highlighting the importance of accounting for these emissions at a national level and investigating mitigation practices.