The current experiment was conducted to quantify methane (CH 4 ) productivity from pig and cattle manure. The manure was collected from twenty commercial farms in different parts of Lithuania. The biogas production and ultimate methane production were measured in a batch experiment according to the international standard. Manure was stored for a period of up to 70 days at constant 35 ± 1°C temperature. Infrared or electrochemical detection was adopted to analyze the methane and carbon dioxide content in biogas. Theoretical methane production was calculated according to the chemical composition of manure. In our study, the theoretical methane production from the total volatile solids (VS) for both pig and cattle manure was in the range of 0.41-0.46 m 3 kg -1 CH 4 VS. Theoretical methane production from easily degradable volatile solids was by 26.72% lower than that from total volatile solids. During the storage period, up to 64% of total manure volatile solids and up to 89% of easily degradable volatile solids had decomposed. The ultimate methane production for pig liquid manure was the highest and reached 0.29 m 3 kg -1 CH 4 VS. The methane production for pig solid fraction of manure was 0.12 m 3 kg -1 CH 4 VS, for the liquid fraction of pig manure -0.18 m 3 kg -1 CH 4 VS. The methane production for dairy cattle liquid and solid manure, also non dairy cattle solid manure reached 0.20-0.21 m 3 kg -1 CH 4 VS. For dairy cattle slurry the methane production was the lowest -0.05 m 3 kg -1 CH 4 VS, in comparison with other samples. Our study showed that methane production for pig and cattle manure in Lithuania was from 13% to 36% lower than the default values recommended for Europe (IPCC Guidelines…, 2006) and are used for calculations of national methane emission from manure.

Livestock manure is the source of different pollutant gases that can generate soil acidification, eutrophication, and contribute to global warming, or have a negative impact on health. Covers can control gas emissions from manure, but their impact is still under discussion. The aim of this experiment was to study the effect of different covers on methane (CH4), nitric oxide (NO), hydrogen sulfide (H2S), ammonia (NH3), carbon monoxide (CO), and carbon dioxide (CO2) emissions from liquid pig manure. Six types of floating covers were tested: light expanded clay aggregate (leca), peat, sunflower oil, sawdust, straw, and plastic film. Manure was stored at 5, 15, and 25 °C for 37 d. Gas emissions were measured from the headspaces of the dynamic chambers. The results of our study showed that both cover and temperature have a noticeable impact on gas emissions from liquid pig manure. The plastic film cover was the most efficient at all tested temperatures because it reduced emissions of all the measured gases. In this case, mean emission reductions were: CH4 91.5% (P < 0.01), NO 92.0% (P < 0.05), H2S 78.1% (P < 0.05), NH3 54.7% (P < 0.01), CO 98.4% (P < 0.01), and CO2 67.1% (P < 0.01). Other covers had an inconsistent impact on separate gas emissions. However, covers generally helped to decrease NH3, H2S, and CO2 emissions.