Fluxes of CO2, CH4, and N2O in an alpine meadow affected by yak excreta on the Qinghai-Tibetan plateau during summer grazing periods

Spatiotemporal Variations in Nitrous Oxide Emissions from an Open Fen on the Qinghai–Tibetan Plateau: a 3-Year Study

“…N 2 O emissions vary considerably and have been influenced by several key factors, such as soil WFPS, pH, C supply, and the weather conditions (Lin et al 2009;Jørgensen et al 2012). However, in this study we only observed significant relation between N 2 O emissions and the 5 cm soil temperatures in 2005.…”

“…On the plateau, the mean N 2 O emission was relatively lower than those from alpine meadows and littoral zones in the same region (Du et al 2008;Chen et al 2011), however, much higher than those from steppes and grasslands of northern and western Qinghai-Tibetan Plateau, which is colder and drier (summarized in Table 4). The possible reason was that N 2 O fluxes in the alpine ecosystem could much more depend on climate conditions because soil temperature and WFPS explained 34-56 % of the variation in N 2 O emissions (Lin et al 2009). Because of marked spatial heterogeneity of environmental and biological factors, there is great spatial variations of N 2 O emissions in wetland ecosystems (Silvan et al 2002;Dhondt et al 2004;Sovik and Klove 2007;van den Heuvel et al 2009;Chen et al 2010Chen et al , 2011Burgin and Groffman 2012).…”

“…This high N 2 O emission in 2006 is also partly due to the accelerated degradation of accumulated organic maters (peat) in the fen when soil aeration increase during the drought (Gorham 1991;Prieme and Christensen 2001). During the drought-induced drainage in 2006, this fen was more available for grazing livestock which increased nitrogen input through dung and urine, resulting in an additional increase in N 2 O emissions (Cardenas et al 2007;Lin et al 2009;Hu et al 2010). In 2007, however, normal precipitation raised the water table from the drought-induced low level.…”

“…Therefore, after seasonal or inter-annual drainage, more easily grazing for livestock is believed to stimulate N 2 O fluxes from wetlands on the plateau. However, it is of great uncertainty that the interaction of abovementioned climate change and grazing on N 2 O fluxes (Lin et al 2009;Wolf et al 2010). …”

“…Though there are several studies about N 2 O fluxes from alpine meadows on the plateau (Pei et al 2003;Lin et al 2009;Hu et al 2010;Jiang et al 2010;Kato et al 2011), only one short-time study was about N 2 O fluxes from littoral marshes (Chen et al 2011). Therefore, to get a whole picture about N 2 O fluxes from wetlands on the QTP, we chose a typical open fen to study its spatial, seasonal, and inter-annual variations of N 2 O fluxes, and to find the key factors controlling such variations.…”