Contribution of urine and dung patches from grazing sheep to methane and carbon dioxide fluxes in an inner mongolian desert grassland

Abstract

The effects of sheep urine and dung patches on methane (CH 4) and carbon dioxide (CO 2) fluxes were investigated during the summer-autumn in 2010, to evaluate their contribution to climate change in a desert grassland in Inner Mongolia, China. Results indicate that the cumulative CH 4 emissions for dung patches, urine patches and control plots were -0.076, -0.084, and -0.114 g/m 2 and these were net CH 4 sinks during the measured period. The level of CH 4 intake from urine and dung plots decreased 25.7%, and 33.3%, respectively, compared with a control plot. CO 2 fluxes differed (p<0.01) in urine plots, with an average of 569.20 mg/m 2/h compared with control plots (357.62 mg/m 2/h) across all sampling days. Dung patches have cumulative CO 2 emissions that were 15.9% higher compared with the control during the 55-d period. Overall, sheep excrement weakened CH 4 intake and increased CO 2 emissions.