2026-10-14T05:42:38Z https://www.scidb.cn/oai

10.57760/sciencedb.43912 2026-07-23T15:18:21Z

2026-07-23 Effects of grazing exclusion duration on soil N2O emission flux in the meadow wetland of Napahai, Yunnan, China. doi:10.57760/sciencedb.43912 en In this study, the typical meadow community in Napahai was taken as the object, and free grazing was used as the control. Three treatments of grazing exclusion for 1 year, 4 year and 7 year were set up. The soil nitrous oxide (N2O) emission flux was determined by static chamber-gas chromatography, and the spatial and temporal variation characteristics were analyzed by logarithmic response ratio (RRi) to analyze the influence mechanism of grazing exclusion years on wetland N2O emissions. The results showed that grazing exclusion significantly promoted soil N2O emissions in meadow wetland, and the RRi value increased with the extension of grazing exclusion duration. The RRᵢ value under the 7-year grazing exclusion treatment was 5.6 times that of the 1-year treatment. Compared with the free grazing control, grazing exclusion significantly increased aboveground and underground biomass (increased by 42.8%-611.9%), and decreased the Margalef, Shannon, Pielou, and Simpson diversity indices of plants (decreased by 15.1%-59.3%). Compared with the control, grazing exclusion significantly increased soil water content, pH, organic matter, total nitrogen, available nitrogen and microbial biomass nitrogen, and reduced bulk density. The soil temperature and inorganic nitrogen (NH4⁺-N, NO3⁻-N) decreased first and then increased with the increase of years. The RRᵢ values of plant biomass, soil water content, pH, organic matter, total nitrogen, available nitrogen and microbial biomass nitrogen all peaked under the 7-year grazing exclusion treatment (increased by 7.5%-352.2%). Correlation analysis showed that N2O emission flux was significantly positively correlated with aboveground biomass, soil water content, pH, and carbon and nitrogen content, and significantly negatively correlated with soil bulk density and plant diversity. The structural equation model (SEM) explained 89.2% of the total variation of N2O emissions, with aboveground biomass (direct effect: 87.5%), soil water content (76.5%), nitrogen content (83.4%), and pH (48.7%) as the main positive driving factors. In summary, short-term grazing exclusion significantly increased soil N2O emissions in the Napahai meadow wetland by increasing plant aboveground biomass, improving soil moisture and nitrogen availability, and optimizing soil aeration (reducing bulk density), and this effect continued to increase with the extension of grazing exclusion duration. grazing exclusion duration; N2O emission; plant diversity; soil property; Napahai; meadow qu jing Lu Mei Cao Shuhan Wang Mingliu Ji Bofan Ren Yulian Yang Zongtao Mushan RESTRICTED dataset Science Data Bank