The biomass and biogas productivity of perennial grasses

Abstract

The current paper presents the results on the biomass and biogas productivity of perennial grasses: tall fescue (Festuca arundinacea Schreb.), cocksfoot (Dactylis glomerata L.) and reed canary grass (Phalaris arundinacea L.). The aim of this study was to evaluate the influence of the timing of the first cut and nitrogen fertilization on biomass and biogas productivity in the first year of sward use. Perennial grasses were grown on an Endocalcari- Endohypogleyic Cambisol (CMg-n-w-can), light loam. During the vegetation season, from April to October the average air temperature was 13.5ºC in 2008 and 12.9ºC in 2009, the precipitation was 336 and 509 mm, respectively. Three and four cuts of grassland per season were combined with 90 and 180 kg ha-1 of mineral nitrogen fertilizer. Our experimental findings suggest that biomass yield differed significantly between grass species. Three-cut and four-cut systems did not influence dry matter (DM) yield significantly. There was no significant difference in productivity of tall fescue and reed canary grass fertilized with N90 and N180; however, cocksfoot, cut for the first time at heading stage and fertilized with N180, produced significantly higher biomass yield, compared to swards, fertilized with N90. The variation of DM yield of tall fescue ranged from 13.37 to 13.84 t ha-1, of cocksfoot from 10.39 to 11.47 t ha-1 and of reed canary grass from 8.27 to 9.41 t ha-1. The specific biogas productivity and energy value of biomass per unit dry matter differed depending on grass species and maturity stage. In biomass of tall fescue it ranged from 10.87 to 14.67 MJ kg-1 DM, of cocksfoot from 10.92 to 16.10 MJ kg-1 DM, and of reed canary grass from 9.68 to 14.33 MJ kg-1 DM. The highest biogas productivity per area was produced by tall fescue swards, cut four times per season, it was 186.1 GJ ha-1. Reed canary grass proved to be the least suitable grass for biogas production from.