Effects of green manure herbage management and its digestate from biogas production on barley yield, N recovery, soil structure and earthworm populations

•Green manure herbage management affected subsequent barley yield and N recovery.•Removal of green manure herbage, compared to mulching, reduced the grain yield.•Application of digested herbage increased herbage N recovered in the barley crop.•Earthworm populations were not negatively affected by one digestate application.