Nitrous Oxide Emissions in Turfgrass Systems: A Review

Core Ideas Turfgrass soils have the potential to emit nitrous oxide at similar rates as agricultural soils. Few turfgrass studies have intensively measured fluxes long enough to calculate accurate annual emissions. Investigation of controlled‐release fertilizers combined with improved irrigation techniques could potentially reduce emissions. Further research is required to develop comprehensive management practices that reduce nitrous oxide emissions in turfgrass. Model simulations should be tested and compared side‐by‐side in turfgrass systems to predict long‐term impacts of management practices. Nitrous oxide (N 2 O) is a natural and anthropogenic by‐product associated with global climate change and potentially the most ozone‐depleting gas. Turfgrass covers large areas of land in the United States, and some is fertilized with N and irrigated with the potential to emit N 2 O at similar rates (i.e., average of 2.7 kg N 2 O–N ha −1 yr −1 ) as agricultural soils. Our objective was to review scientific literature on N 2 O emissions in turfgrass and identify knowledge gaps and future research needs. Few turfgrass studies exist in which fluxes were intensively measured for long enough to calculate accurate annual emissions, which have ranged from 1.01 to 7.6 kg N 2 O–N ha −1 yr −1 in various turf species receiving N fertilizer, and from 0.5 to 2.24 kg N 2 O–N ha −1 yr −1 in unfertilized turf species. Research indicates reduced irrigation and controlled‐release forms of N may slow nitrification and denitrification processes, and thus, reduce N 2 O emissions in turfgrass. Future research should be directed toward long‐term investigations of controlled‐release fertilizers (e.g., investigating N application amounts, seasonal application timings, and differences between warm‐ and cool‐season turfgrass species) combined with irrigation techniques (e.g., irrigation quantity, frequency, and application timing surrounding fertilization events) to minimize N 2 O emissions, maximize plant nutrient uptake, and determine more efficient application methods that reduce emissions and water use in warm‐ and cool‐season turfgrass species. The use of model simulations (i.e., DAYCENT and DNDC) should be further developed for turfgrass systems to predict long‐term impacts of different management practices on C and N cycling in turfgrass.