Zhifeng Xun

and 4 more

Lawn is the primary vegetation utilized for urban sporting grounds and garden greenbelts. The N fertilizer addition induced higher N2O emission in various soils including the lawn soil, however, a key gap in knowledge lies in identifying the ecological consequences of the N2O emission and potentially associated microbial mechanisms. N2O is a product of microbial participation in nitrogen transformation processes, which is closely related to the use of nitrogen fertilizer. This study evaluated the effect of N fertilizer on N2O emissions and associated microbial mechanism in lawn soil through incubated experiment under different N application rates [300 kg ha yr-1 (N300), 225 kg ha yr-1 (N225), 150 kg ha yr-1 (N150) and control (N0)]. In addition, the contribution of different microbial communities to N2O emissions was quantified by combining biological inhibitors with high-throughput sequencing. The results indicated that N fertilizer addition induced higher N2O emissions in lawn soil, showed the highest in the N225 treatment. The contribution of fungi to N2O emissions was 45%, significantly higher than that of bacteria (31%). The dominant fungi in the lawn soil included Ascomycota, Basidiomycota, and Mucoromycota. N fertilizer significantly increased the relative abundance of Ascomycota and decreased the relative abundance of Basidiomycota. We found a positive correlation between N2O emission and Ascomycota through RDA analysis. The growth trend of Ascomycota during the four nitrogen fertilizer treatments was consistent with the N2O emission trend in lawn soil. N2O emissions reached their highest levels after the N225 treatment. The relative abundance of Pyrenochaetopsis, Myrothecium, and Humicola was positively correlated with N2O emission. Thus, Pyrenochaetopsis, Myrothecium, and Humicola were found to be the main functional microorganisms leading to N2O production in lawn soil. Our findings can deepen the understanding on N2O emission and associated microbial mechanism in lawn soil with N fertilization.