Anaerobic digestion of co-ensiled cover crop and barley straw: Effect of co-ensiling ratios, manure addition and impact on microbial community structure

•Anaerobic digestion of co-ensiled cover crop and straw with manure were tested.•Cover crop is feasible for biogas either alone or together with straw, manure or both.•Co-digestion of cover crops with manure and less straw had superior performance.•High straw addition led to distinct microbial communities.