The effects of air stress during storage, exposure to air at feed-out, and treatment with silage additives to
enhance aerobic stability on methane production from maize silage were investigated at laboratory scale.
Up to 17% of the methane potential of maize without additive was lost during seven days exposure to air
on feed-out. Air stress during storage reduced aerobic stability and further increased methane losses.
A chemical additive containing salts of benzoate and propionate, and inoculants containing heterofermentative
lactic acid bacteria were effective to increase aerobic stability and resulted in up to 29% higher
methane yields after exposure to air. Exclusion of air to the best possible extent and high aerobic
stabilities should be primary objectives when ensiling biogas feedstocks