Effects of co-digestion of cucumber residues to corn stover and pig manure ratio on methane production in solid state anaerobic digestion.

•Cucumber residues was a good potential materiel for methane production.•Co-digestion leads to increasing methane production compared to mono-feedstock.•The highest methane yield feed was achieved with a 5:2:3 ratio of PM with CS and CR.•Significant regularity of methane yields was obtained with different CR ratio.•Regularity of methane production and microbial communities structure was obtained.