Effects of Mowing on Methane Uptake in a Semiarid Grassland in Northern China

Background: Mowing is a widely adopted management practice for the semiarid steppe in China and affects CH4 exchange. However, the magnitude and the underlying mechanisms for CH 4 uptake in response to mowing remain uncertain. Methodology/Principal Findings: In two consecutive growing seasons, we measured the effect of mowing on CH 4 uptake in a steppe community. Vegetation was mowed to 2 cm (M2), 5 cm (M5), 10 cm (M10), 15 cm (M15) above soil surface, respectively, and control was set as non-mowing (NM). Compared with control, CH4 uptake was substantially enhanced at almost all the mowing treatments except for M15 plots of 2009. CH4 uptake was significantly correlated with soil microbial biomass carbon, microbial biomass nitrogen, and soil moisture. Mowing affects CH 4 uptake primarily through its effect on some biotic factors, such as net primary productivity, soil microbial C\N supply and soil microbial activities, while soil temperature and moisture were less important. Conclusions/Significance: This study found that mowing affects the fluxes of CH4 in the semiarid temperate steppe of north China