Biogas yields from grassland

Biogas production is a suitable way of energetic use of surplus grassland. The influence of grass species, cutting periods, intensity of grassland use, and ensiling additives on biogas and methane yields was investigated in combined field and laboratory tests. Methane yields of grassland biomass vary in a wide range, mainly depending on the intensity of grassland use. As a rule, an intensive management with an early first cut and several cuts per year leads to both high substrate-specific and area-specific methane yields and vice versa. The influence of grass species and ensiling additives on substrate-specific methane yields seems to be secondary. Further systematic research on optimal grassland management for biogas production and on environmental and socio-economic impacts is required.