Nitrous Oxide Emissions from Turfgrass Lawns as a Result of Fertilizer Application:A Meta-Analysis of Available Literature

Urban turfgrass lawns are known to contribute towards global anthropogenic nitrous oxide emissions. However, available literature on lawn N₂O emissions is varied and inconclusive. To our knowledge, an effort to compile and understand urban lawn N₂O emissions is, as yet, lacking. In th e present article, a meta-analysis was conducted to evaluate the effect of lawn fertilizer application on N₂O emissions relative to no-fertilizer application, along with an examination of the variation of this effect with respect to the type and amount of fertilizer. The results show that lawn N₂O emissions from fertilized plots are significant and are 41% (0.29 g N₂O–N/m 2 /year) higher than that of control plots. However, studies with low N -input (<150 kg/ha) show higher percentage (40) of N₂O emission than those with high N-input (22). Further , N₂O emissions are higher for urea application plots (37%) compared to other -than-urea plots (30%), which consisted mostly of enhanced efficiency fertilizer plots. Overall, the results of this meta -analysis under-score current understand ings of the effect of fertilizer on soil N₂O emissions, although it indicates that fertilizer amount is not the only driver of lawn N₂O emissions. Also, the sub-group analysis of fertilizer type reinforces the importance of enhanced eff iciency fertilizers in reducing emissio ns which has clear policy implications. To improve our understan ding of lawn N₂O emissions, more long-term studies that are well-documented, and geographically widespread, are re commended to build a database that can reduce uncertainties and facilitate lon g-term evaluations.