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.
2006
Forfattere
Anne Falk ØgaardSammendrag
Det er ikke registrert sammendrag
Forfattere
Tor Håkon SivertsenSammendrag
An interpretation of the scientific principle ( as this is used in the context of agro meteorology ) is presented and discussed, containing the concepts of classification of meteorological and biological phenomena, parameterization, testing and use of models. The ideas of pure and applied science are presented, and then the concept of scope of the scientific principle is discussed. Both the use of science for understanding nature, the use of science for implementing applications, and the use of science for understanding the consequences of the use of applications are contained in this discussion. The views and discussion are also extended towards society, and what should be the content of sustainable agricultural production. The concept of the relations of human beings to othe biological organisms and to past and future generations is a part of this discussion. References: Philip, J.R, (1991), Soils, natural science, and models, Soil science. 151:91-98 Addiscott, T.M., (1993), Simulation modelling and soil behaviour, Geoderma, 60: 15-40 Sivertsen, T.H.,(2004) Invitation to Conceptual Discussions Concerning the Scope of the Scientific Method and Classification of Meteorological Phenomena and Meteorological Parameters, P 185-190, Selected Papers of the International Conference `Fluxes and Structures in Fluids", St. Petersburg, Russia, June 23-26, 2003, Moscow, IPM RAS, 2004 Sivertsen T.H., 2005, Discussing the scientific method and a documentation systems of meteorological and biological parameters, Physics and Chemistry of the Earth Special Issue: Agrometeorology 2003, Vol 30/1-3 pp 35-43 Sivertsen, T.H., 2005, Discussing scientific methods and the quality of meteorological data, in `Use and Availability of Meteorological Information from Different Sources as Input in Agrometeorological Models", COST ACTIONS 718 `Meteorological Applications for Agriculture", Edited by G. Maracchi, A. Mestre, L. Toulios and B. Gozzini. Sivertsen, T.H, 2005, ", Reflections on the Theme of Classifying, Documenting and Exchanging Meteorological Data", Atmospheric Science Letters, Vol.6 , Issue 3, p 171-175, John Wiley & Sons
Forfattere
L.H. Pardo P.H. Templer C.L. Goodale S. Duke P.M. Groffman M.B. Adams P. Boeckx J. Boggs J. Campbell B. Colman J. Compton Bridget A. Emmett Per Gundersen O. Janne Kjønaas G. Lovett M. Mack A. Magill M. Mbila M.J. Mitchell G. McGee S. McNulty Knute J. Nadelhoffer S. Ollinger D. Ross H. Rueth L. Rustad P. Schaberg S. Schiff Patrick Schleppi J. Spoelstra W. WesselSammendrag
N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar d15N may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root d15N and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar d15N than the regional driver of N deposition. Foliar d15N increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar d15N was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root d15N was more tightly coupled to forest floor properties than was foliar d15N. We observed a pattern of decreasing foliar d15N values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar d15N included species composition and climate. Relationships between foliar d15N and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar d15N, due to the importance of ammonium deposition in this region. Our results suggest that examining d15N values of foliage may improve understanding of how forests respond to the cascading effects of N deposition. Introduction Nitrogen saturation is the process by which chronically elevated N inputs alter forest ecosystems, ultimately resulting in increases in ecosystem N loss (Aber et al. 1989; 1998). N saturation can result in detrimental plant responses and have serious consequences for forest health (Nihlgard 1985; Aber et al. 1989; Schaberg et al. 2002) and may impact forests in many regions (Dise et al. 1998; Aber et al. 2003). Therefore, developing indicators useful for determining whether a forest is at N saturation and for predicting when a forest is nearing N saturation is valuable. Such indicators would facilitate both forest management and understanding of N cycling in forest ecosystems.
Forfattere
Linda H. Pardo P. H. Templer C. L. Goodale S. Duke P. M. Groffman M. B. Adams P. Boeckx J. Boggs J. Campbell B. Coleman J. Compton Bridget A Emmett Per Gundersen O. Janne Kjønaas G. Lovett M. Mack Alison Magill M. Mbila Myron J. Mitchell G. McGee Steven McNulty Knute Nadelhoffer S. Ollinger D. Ross H. Rueth Lindsey Rustad P. Schaberg Sheryl Schiff Patrick Schleppi J Spoelstra Wim WesselSammendrag
N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar d15N may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root d15N and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar d15N than the regional driver of N deposition. Foliar d15N increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar d15N was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root d15N was more tightly coupled to forest floor properties than was foliar d15N. We observed a pattern of decreasing foliar d15N values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar d15N included species composition and climate. Relationships between foliar d15N and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar d15N, due to the importance of ammonium deposition in this region. Our results suggest that examining d15N values of foliage may improve understanding of how forests respond to the cascading effects of N deposition.
Sammendrag
We examined growth responses of Norway spruce using tree-ring series from increment cores and monthly climate variables over the period 19001998. The 1398 cores were selected from 588 plots scattered all over Norway. We correlated tree-ring indices with temperature, precipitation, Palmer drought severity index and length of the growing season.The weather in June had the largest influence on ring widths. However, two different, and almost opposite, response types were found: Tree growth was restricted by June precipitation in the lowlands in southeastern Norway, but by the June temperature in other regions and at high altitudes.In order to define the shift between these two main response types, we correlated response functions with various 30-year mean climatic variables, including humidity and aridity indices. The 30-year mean June temperature was the variable most clearly showing this shift in response, with a threshold at 1213C. At sites with normal temperature below this threshold, spruce responded positively to unusually warm and dry June months, and vice versa.
Forfattere
Ellen Johanne SvalheimSammendrag
På oppdrag av Fylkesmannens landbruksavdeling i Aust-Agder har Svalheim registrert biomangfoldverdier og gjengroing i kulturlandskapet fra Valle sentrum til Tveiten i Valle kommune i Aust-Agder, somrene 2005/2006. Rapporten oppsumerer disse registreringene.
Sammendrag
Markedet blir stadig presentert for nye gjødseltyper. Den tyske gjødsla Entec er en slik ny gjødseltype, og fås både som NPK-gjødsel og som ren N-gjødsel. Gjennom forsøk i tre år er den blitt prøvd i kulturene løk, purre og salat ved Planteforsk Landvik. Styrt næringsforsyning gjennom dryppvanning er blitt vanlig på frilandskulturer i bær, men forsøk de senere år viser at bruk av samme teknikk kan være avgjørende for utbytte og kvalitet hos frilandssalat.
Forfattere
Christian UhligSammendrag
Nye forskningsresultater indikerer en sammenheng mellom lavbeitenes nedslitningsgrad og forringelsen av jordsmonn. Omfanget av jorddegradasjon er ikke kjent. Dersom omfanget av jordforringelse er like utbredt som reduksjon av lavdekke de siste 30 år, er dette en alvorlig trussel for reinbeitene på Finnmarksvidda.
Forfattere
Christian UhligSammendrag
Beitende pattedyr kan ha stor innvirkning på jordsmonnets fertilitet gjennom tilføring av avføring og tråkk. For arktiske herbivorer som reinsdyr har det hittil vært antatt at de øker beitenes fertilitet. Resultater fra nyere undersøkelse viser derimot at dette ikke er tilfelle for beitene på Finnmarksvidda, hvor det ble påvist at reinbeite kan føre til jordforringelse. Hovedmålet med denne presentasjonen er å finne en forklaring på de åpenbart motsigende påstandene ved å sammenstille resultatene om herbivorenes innflytelse på beitenes fertilitet. Resultatene viser at herbivorer kan påvirke beitenes kvalitet på alle tenkbare måter: positiv, negativ og ikke målbart. Generelt viser det seg at økosystemets respons på beiting er avhengig av dets evne til å nyttiggjøre seg avføringens næringsstoffer, og dermed dens betydning på systemets primær- produksjon og næringssyklus. På steder hvor beiting øker den langsiktige næringssyklusen vil dette føre til økt fertilitet og dermed økt beitekvalitet. Det motsatte kan derimot forventes på steder hvor beiting minker næringssyklusen. Ved å overføre dette konseptet til de lavdominerte vinterbeitene på Finnmarksvidda ble følgende funnet. De lett bio-tilgjengelige næringsstoffene fra reinens avføring ble tilført systemet i en periode med forholdsvis lav biologisk aktivitet som dermed har liten evne til å fiksere dem. I tillegg havner reinens urin og møkk ofte i snøen eller på frossen mark, og blir dermed ikke umiddelbart tilført jordmonnets næringspool. Den sesongbestemte utsatte tidsforskjell mellom reinens tilgjengeliggjøring av essensielle næringsstoffer om vinteren og deres biologiske assimilasjon øker risikoen for tap av disse, spesielt under snøsmeltings perioder om våren. Samtidig bestemmes økosystemets fysiske evne til å holde på næringsstoffene av dets kationbyttekapasitet (KAK). På de lavdominerte beitene på Finnmarksvidda er det humus og reinlav som utgjør det meste av systemets KAK, og begge blir negativ påvirket av reinbeite. Jordforringelsen på Finnmarksvidda kan dermed, i hvert fall delvis, forklares gjennom en ukomplett næringssyklus som resultat av både beitetidspunkt og en i utgangspunktet lav jordfertilitet. Reinbeite, spesielt om vinteren, øker dermed ikke nødvendigvis beitenes kvalitet.
Sammendrag
There is increasing awareness of the need to monitor trends in our constantly changing agricultural landscapes. Monitoring programmes often use remote sensing data and focus on changes in land cover/land use in relation to values such as biodiversity, cultural heritage and recreation.Although a wide range of indicators is in use, landscape aesthetics is a topic that is frequently neglected. Our aim was to determine whether aspects of landscape content and configuration could be used as surrogate measures for visual landscape quality in monitoring programmes based on remote sensing.In this paper, we test whether map-derived indicators of landscape structure from the Norwegian monitoring programme for agricultural landscapes are correlated with visual landscape preferences. Two groups of people participated: (1) locals and (2) non-local students.Using the total dataset, we found significant positive correlations between preferences and spatial metrics, including number of land types, number of patches and land type diversity. In addition, preference scores were high where water was present within the mapped image area, even if the water itself was not visible in the images.When the dataset was split into two groups, we found no significant correlation between the preference scores of the students and locals. Whilst the student group preferred images portraying diverse and heterogeneous landscapes, neither diversity nor heterogeneity was correlated with the preference scores of the locals.We conclude that certain indicators based on spatial structure also have relevance in relation to landscape preferences in agricultural landscapes. However, the finding that different groups of people prefer different types of landscape underlines the need for care when interpreting indicator values