Methane Emission from Sheep Respiration and Sheepfolds During the Grazing Season in a Desert Grassland

ABSTRACT

Methane (CH₄) emissions from ruminants should be accounted for the natural grazed rangeland ecosystems when devising greenhouse gas budget inventory, in particular, their contribution to global warming. In this study, CH₄ emission from sheep respiration at different grazing intensities (light grazing, 0.75 sheep/ha, LG; moderate grazing, 1.50 sheep/ha, MG; and heavy grazing, 2.25 sheep/ha, HG) and in sheepfolds were evaluated in a desert grassland of Inner Mongolia. Results indicated that daily CH₄ emission from sheep was not significantly different between treatments. When CH4 emission was expressed emission per 100g daily, there was a significant difference of LG vs HG and MG vs HG, with the values of 15.64g, 20.00g and 28.63g for LG, MG and HG, respectively, during the grazing season. There was no significant difference among CH₄ fluxes in sheepfolds (mean 39.0 ug m^-2 h^-1). Considering CH₄ emissions from the grazing ecosystem, net CH₄ emissions from LG, MG and HG plots were -18.33, -1.91 and 21.19 g/ha/day, respectively. The digestibility of forage had a positive correlation with CH₄ emission expressed on daily and metabolic body weight basis. It is concluded that MG will improve the balance between CH₄ emission from grassland and grazing livestock in the desert grasslands of Inner Mongolia.

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