Synergetic effect of combined ensiling of freshly harvested and excessively wilted maize stover for efficient biogas production.

This study investigated the synergetic effects of ensiling freshly harvested maize stover (FHM) and excessively wilted maize stover (EWM) on biogas production. FHM and EWM were mixed in various proportions to obtain dry matter (DM) contents of 30%, 35% and 40%. For reference, FHM alone was ensiled and stored in open-air. Successful storage performance was obtained by the ensiling treatments, and the organic matter loss of 1.1-2.2% was far lower than in open-air storage (63.1%). An initial water-soluble carbohydrate (WSC) of 5% DM is adequate for the combined ensiling of maize stover with the highest WSC degradation rate of 81.2%. Combined ensiling enhanced the activity of Weissella, a genus of heterofermentative lactic acid bacteria, under relatively high pH conditions. Therefore, the combined ensiling can preserve FHM and enhance the digestibility of EWM (theoretical specific methane yield increased 16.5%), which would be a promising storage strategy for efficient biogas production.