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.
2021
Sammendrag
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Sammendrag
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Forfattere
Ishita AhujaSammendrag
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Forfattere
Knut Ole VikenSammendrag
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Forfattere
Diego Abalos Tatiana Francischinelli Rittl Sylvie Recous Pascal Thiébeau Cairistiona F. E. Topp Kees Jan van Groenigen Klaus Butterbach-Bahl Rachel E. Thorman Kate E. Smith Ishita Ahuja Jørgen E. Olesen Marina Azzaroli Bleken Robert M. Rees Sissel HansenSammendrag
Crop residue incorporation is a common practice to increase or restore organic matter stocks in agricultural soils. However, this practice often increases emissions of the powerful greenhouse gas nitrous oxide (N2O). Previous meta-analyses have linked various biochemical properties of crop residues to N2O emissions, but the relationships between these properties have been overlooked, hampering our ability to predict N2O emissions from specific residues. Here we combine comprehensive databases for N2O emissions from crop residues and crop residue biochemical characteristics with a random-meta-forest approach, to develop a predictive framework of crop residue effects on N2O emissions. On average, crop residue incorporation increased soil N2O emissions by 43% compared to residue removal, however crop residues led to both increases and reductions in N2O emissions. Crop residue effects on N2O emissions were best predicted by easily degradable fractions (i.e. water soluble carbon, soluble Van Soest fraction (NDS)), structural fractions and N returned with crop residues. The relationship between these biochemical properties and N2O emissions differed widely in terms of form and direction. However, due to the strong correlations among these properties, we were able to develop a simplified classification for crop residues based on the stage of physiological maturity of the plant at which the residue was generated. This maturity criteria provided the most robust and yet simple approach to categorize crop residues according to their potential to regulate N2O emissions. Immature residues (high water soluble carbon, soluble NDS and total N concentration, low relative cellulose, hemicellulose, lignin fractions, and low C:N ratio) strongly stimulated N2O emissions, whereas mature residues with opposite characteristics had marginal effects on N2O. The most important crop types belonging to the immature residue group – cover crops, grasslands and vegetables – are important for the delivery of multiple ecosystem services. Thus, these residues should be managed properly to avoid their potentially high N2O emissions.
Forfattere
Ishita AhujaSammendrag
Det er ikke registrert sammendrag
Forfattere
Ishita AhujaSammendrag
Det er ikke registrert sammendrag
Sammendrag
Over recent decades, climate change has been particularly severe in the Mediterranean basin, where the intensity and frequency of drought events have had a significant effect on tree growth and mortality. In this context, differences in structural and physiological strategies between tree species could help to mitigate the damage inflicted by climate variability and drought events. Here, we used dendroecological approaches to observe common associations (synchrony) between indexed ring width in Pinus pinea and P. pinaster, as a measure of degree of dependence on climate variation or growth sensitivity to climate, as well as to analyze species growth responses to drought events through the Lloret’s indices of resistance, recovery and resilience. Based on data from 75 mixed and pure plots installed in the Northern Plateau of Spain, we used modeling tools to detect the effect of the mixture, along with climate and stand-related variables, on the short-term responses and long-term growth sensitivity to climate. Our results showed a trade-off between resistance and recovery after the drought episodes. In addition, different attributes of tree species, such as age and size as well as stand density seemed to act synergistically and compensate drought stress in different ways. The presence of age and quadratic mean diameter as covariates in the final synchrony model for P. pinaster reflected the influence of other variables as modulators of growth response to climate. Furthermore, differences in growth synchrony in mixed and monospecific composition suggested the existence of interactions between the two species and some degree of temporal niche complementarity. In mixed stands, P. pinaster exhibited a lower sensitivity to climate than in monospecific composition, whereas P. pinea enhanced its resistance to extreme droughts. These results allowed us to identify the species-specific behavior of P. pinea and P. pinaster to mitigate vulnerability to climate-related extremes.
Sammendrag
Hovedmålet i dette prosjektet har vært å undersøke egenskapene til konstruksjonsvirke av furu fra Troms og Finnmark. Tidligere undersøkelser av furu fra dette området har blitt gjennomført på små, feilfrie prøver, og det er behov for å dokumentere egenskaper til trelast i bruksdimensjoner for å vurdere om kravene til konstruksjonsvirke oppfylles. Materialet ble samlet inn fra tre bestand i Pasvik, ett i Karasjok, to i Alta og fire i Bardufoss. Fra hvert bestand ble det ble tatt ut 12 trær, som ga totalt 650 planker. Trelasten ble visuelt styrkesortert etter NS-INSTA 142, og densitet, E-modul og bøyefasthet ble testet i henhold til NS-EN 408. Gjennomsnittlig bøyefasthet (40,5 N/mm2) var noe lavere enn det som er funnet for furu lenger sør i Norden. Det samme gjelder gjennomsnittlig E-modul (10,3 kN/mm2) og gjennomsnittlig densitet (448 kg/m3)...
Forfattere
Ruth Jaén-Molina Águedo Marrero-Rodríguez Juli Caujapé-Castells Dario Isidro Ojeda AlayonSammendrag
With a wide distribution range including Europe and Asia, Lotus (Leguminosae) represents the largest genus within Loteae. It is particularly diverse in the Mediterreanean region and in the five archipelagos of Macaronesia (Atlantic Ocean). However, little is known about the relationships among the 14 sections currently recognized within Lotus and about the timing and patterns of its colonization in the Macaronesian region. In this investigation, we use four DNA regions (nuclear ribosomal ITS plus three plastid regions) in the most comprehensive sampling of Lotus species to date (some endemic species within the Canary Islands were poorly represented in previous phylogenetic analyses) to infer relationships within this genus and to establish patterns of colonization in Macaronesia. Divergence time estimates and habitat reconstruction analyses indicate that Lotus likely diverged about 7.86 Ma from its sister group, but all colonization events to Macaronesia occurred more recently (ranging from the last 0.23 to 2.70 Ma). The diversification of Lotus in Macaronesia involved between four and six independent colonization events from four sections currently distributed in Africa and Europe. A major aspect shaping the current distribution of taxa involved intra-island colonization of mainly new habitats and inter-island colonization of mostly similar habitats, with Gran Canaria and Tenerife as the major sources of diversification and of further colonization events. Section Pedrosia is the most diverse in terms of colonization events, number of species, and habitat heterogeneity, including a back-colonization event to the continent. Subsections within Pedrosia radiated into diverse habitat types recently (late Pleistocene, ca 0.23–0.29 Ma) and additional molecular markers and sampling would be necessary to understand the most recent dispersal events of this group within the Canary Islands and Cape Verde.