BIOGAS PRODUCTION FROM GRASSES

Fodder galega (Galega orientalis Lam.) and red clover (Trifolium pratense) are fodder legumes having high productivity and capacity to fix atmospheric nitrogen, so reducing the need for N-fertilisers. Reed canary grass (Phalaris arundinacea) can be harvested during long periods without reseeding and without application of pesticides. Investigated dry matter yields were 9.6-11.2 t ha(-1), 8-13 t ha(-1) and 7-11 t.ha(-1) for galega, red clover and reed canary grass respectively. Methane yields obtained in digesters were 218.6 l.kgV0S(-1) from cow's manure (control) and 384.2 l.kgVSd(-1), 309.2 l.kg l.kgVSd(-1), 244 l.kg l.kgVSd(-1) from different galega-cow's manure mixtures. Estimated volumes of methane released from galega haylage, in dependence of high and low organic load, were 46.8 and 119.6 l.kgVSd(-1) respectively. Methane production from red clover was 245.4 and 222.8 l.kgVSd(-1). Methane yield from reed canary grass fresh biomass was 141.1 and 126.7 l.kgVSd(-1).