The effects of seven mixing ratios (1:0, 3:1, 2:1, 1:1, 1:2, 1:3, and 0:1, swine manure (SM)/rice straw (RS), based on total solid) on anaerobic co-digestion (co-AD) of SM and RS mixtures were investigated in batch tests. The results showed that the highest methane yield (188.79mL/g VSadded) was obtained at the ratio of 1:1, which was higher than that of the mono-digestion of RS or SM by 178.77% and 18.94%, respectively. For the remained six ratios, the methane yield increased with the increase of SM proportion. The highest organic matter degra...