Experiments on influencing factors of methane emissions from beef cattle manure stack

To explore the impacts of major influencing factors on methane emissions from manure, methane emission fluxes of beef cattle manure under different temperatures and manure stack heights were measured by dynamic chamber technique. The experiments regulated the temperatures of 15℃, 25℃, 35℃, and took measurements on methane emissions during manure ventilated storage with stack height of 10, 20, 40 cm, respectively. Moreover, chemical properties of the manure were analyzed for the initial and post stored manure. Experimental results showed that the methane emission flux and cumulative emission during a 15-day ventilated storage period under 15℃ was (0.031±0.002)～(0.002±0.000) g/(d·kg) and 0.17～0.18 g/kg, (0.323±0.018)～(0.051±0.063) g/(d·kg) and 3.8～5.1 g/kg during a 26-day ventilated storage period under 25℃, (0.414±0.073)～(0.033±0.050) g/(d·kg) and 3.6～6.6 g/kg during a 26-day ventilated storage period under 35℃. Manure methane emission rate at 15℃ was significantly lower than the emission at 25℃ and 35℃(P＜0.01). The research allows for development of empirical model that estimates methane emissions from stored manure for different stack heights.