Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2017
Forfattere
Mirzaman Zamanzadeh Live Heldal Hagen Kine Svensson Roar Linjordet Svein Jarle HornSammendrag
In this work, performance and microbial structure of a digestion (food waste-only) and a co-digestion process (mixture of cow manure and food waste) were studied at mesophilic (37°C) and thermophilic (55°C) temperatures. The highest methane yield (480mL/g VS) was observed in the mesophilic digester (MDi) fed with food waste alone. The mesophilic co-digestion of food waste and manure (McoDi) yielded 26% more methane than the sum of individual digestions of manure and food waste. The main volatile fatty acid (VFA) in the mesophilic systems was acetate, averaging 93 and 172mg/L for McoDi and MDi, respectively. Acetate (2150mg/L) and propionate (833mg/L) were the main VFAs in the thermophilic digester (TDi), while propionate (163mg/L) was the major VFA in the thermophilic co-digester (TcoDi). The dominant bacteria in MDi was Chlorofexi (54%), while Firmicutes was dominant in McoDi (60%). For the mesophilic reactors, the dominant archaea was Methanosaeta in MDi, while Methanobacterium and Methanosaeta had similar abundance in McoDi. In the thermophilic systems, the dominant bacteria were Thermotogae, Firmicutes and Synergistetes in both digesters, however, the relative abundance of these phyla were diferent. For archaea, the genus Methanothermobacter were entirely dominant in both TDi and TcoDi.
Forfattere
Radziah Wahid Kine Svensson Daniel Girma Mulat Svein Jarle HornSammendrag
Det er ikke registrert sammendrag
Forfattere
Erik J. JonerSammendrag
Det er ikke registrert sammendrag
Forfattere
Daniel RasseSammendrag
Det er ikke registrert sammendrag
Forfattere
Adam Thomas O'tooleSammendrag
Det er ikke registrert sammendrag
Forfattere
Adam Thomas O'tooleSammendrag
Det er ikke registrert sammendrag
Forfattere
Erik J. JonerSammendrag
Det er ikke registrert sammendrag
Forfattere
Erik J. JonerSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Aims: Evaluate biological nitrogen fixation (BNF) and its contribution to total N yield in different grass-clover mixtures under a boreal coastal climate and assess how winter conditions affect the survival of clover and its capability to fix nitrogen (N). Methods: Grass-clover mixtures sown with 0, 15 and 30% red and white clover were subjected to two N rates and three levels of tractor trafficking over four years. BNF was estimated by N-difference for each of the two harvests per year, whereas the first harvest was used to estimate the fraction of N derived from the atmosphere (NdfA) and its transfer to grasses by 15N natural abundance. Results: Biological N fixation, mainly by red clover, contributed substantially to total N yield, which was up to 75% greater in grass-clover mixtures than in pure grass stands in the second production year. However, the number of red clover plants and associated BNF decreased dramatically in the third and fourth production year, with N fertilization rate having a more detrimental effect than soil trafficking. Conversely, the amount of biologically fixed N transferred to grass, increased with time, evidencing that some of the biologically fixed N is retained in the system. In the first harvests, NdfA values were generally between 80 and 100%, irrespective of preceding winter conditions. Conclusions: BNF in high latitude grass-clover mixtures can be substantial but is limited by the poor survival of red clover. Variable winter conditions had no measurable effect on winter survival nor on the sward’s capacity to fix nitrogen in spring.