Cocksfoot, tall fescue and reed canary grass: Dry matter yield, chemical composition and biomass convertibility to methane

The study was aimed to select productive accessions of tall fescue (Festuca arundinacea), cocksfoot (Dactylis glomerata) and reed canary grass (Phalaris arundinacea) by screening germplasm collection, as well as to ascertain the influence of grass maturity on quality of the biomass and it convertibility to the methane. In spaced stand trial, according to the dry matter yield (DMY) per plant (sum of 3 cuts per 2 years) the Lithuanian cvs. Aukštuolė and Navas DS proved to be the most high-yielding accessions (407.7 g and 396.0 g) among the cocksfoot, and tall fescue, respectively, while American cv. Palaton (382.1 g) – among reed canary grass. In the dense stand trial, the annual DMY of Palaton was 12.79 t ha−1 and that of the cvs. Navas DS and Aukštuolė amounted to 10.32 t ha−1 and 10.22 t ha−1. Advancing maturity from the early heading until full flowering increased total solids in the biomass of all the three species by 50.6%–55.6%, the values of NDF digestion by cellulolytic enzymes changed by (−48.0)% to (−58.0) %. The specific methane yields of all grass species and at all development stages varied from 266 L kg−1 VS to 426 L kg−1 VS. The alteration in the bioenergy potential and quality of cocksfoot biomass with advanced maturity stage occurred not as sharply as that of reed canary grass and tall fescue. The dependence of methane yield and energy value of biomass on the chemical composition of herbage was examined.