초록
<P><B>Abstract</B></P> <P>Grassland biomass is likely to be harvested and stored as silage to ensure a predictable quality and a constant supply of feedstock to an anaerobic digestion facility. Grass (<I>Phleum pratense</I> L. var. Erecta) was ensiled following the application of one of six contrasting additive treatments or a 6？h wilt treatment to investigate the effects of contrasting silage fermentation characteristics on CH<SUB>4</SUB> yield. In general, silage fermentation characteristics had relatively little effect on specific CH<SUB>4</SUB> yield (from 344 to 383 Nl CH<SUB>4</SUB> kg<SUP>−1</SUP> volatile solids). However, the high concentrations of fermentation products such as ethanol and butyric acid following clostridial and heterofermentative lactic acid bacterial fermentations resulted in a numerically higher specific CH<SUB>4</SUB> yield. While the latter fermentation products of undesirable microbial activity have the potential to enhance specific CH<SUB>4</SUB> yield, the numerically higher specific CH<SUB>4</SUB> yield may not compensate for the associated total solids and energy losses during ensiling.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Grass silages of contrasting fermentation characteristics have similar CH<SUB>4</SUB> yields. </LI> <LI> Undesirable fermentation products can potentially enhance specific CH<SUB>4</SUB> yield. </LI> <LI> Higher specific CH<SUB>4</SUB> yields may not compensate for in-silo losses during ensiling. </LI> </UL> </P>