Effects of plant communities on the emission of soil greenhouse gases in riparian wetlands during spring thaw

Abstract

Spring thawing can affect the soil carbon and nitrogen cycling processes and lead to changes in the emissions of greenhouse gases. The temporal variations and impact factors of soil GHGs fluxes were measured in Phragmites australis and Carex appendiculata with the static chamber from the end of March to the end of May in 2018 in riparian wetlands of Xilin River, which is typical inland river meandering through steppe region in Inner Mongolia, China. The results showed that soil CH4 and N2O emissions of the Phragmites australis were significantly higher than those of the Carex appendiculata, whereas CO2 emissions were no significant difference. The responses of soil GHG fluxes to soil environmental factors in Phragmites australis and Carex appendiculata differed. In the Phragmites australis community, soil CO2 and CH4 emissions were influenced jointly by mainly the soil temperature, and microbial biomass nitrogen, whereas soil N2O emission was mainly affected by the soil temperature. The dominant controlling factor for CO2 and N2O was soil temperature in the Carex appendiculata, whereas CH4 was mainly regulated by soil water content. The global warming potential of Phragmites australis was significantly higher than that of Carex appendiculata. Those findings highlight the difference in soil greenhouse gas fluxes in different plant communities and the importance of CH4 and N2O emissions during the spring thaw, which contributes to predicting the riparian wetland soil greenhouse gases and their global warming potential under global climate changes.