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
Tor Gunnar Vågen Keith D. Shepherd Markus G. WalshSammendrag
Sensing landscape level change in soil fertility following deforestation and conversion in the highlands of Madagascar using Vis-NIR spectroscopy. Research data on soil quality are scarce in Madagascar, despite the island"s widely recognized problems of soil and environmental degradation. One of the major constraints to properly assessing current status, trends and processes of soil degradation is the high level of costs involved when using conventional soil analytical methods. Previous studies have demonstrated that visible-near-infrared (Vis-NIR) reflectance spectroscopy may permit rapid and cost effective analysis of tropical soils that could provide new opportunities for farmers, land managers, local authorities and researchers in assessing and managing soil quality. This study tested the potential of Vis-NIR soil spectral libraries for predicting and mapping soil properties in the eastern highlands of Madagascar. Stable calibration models were developed for several key soil properties. Cross-validated r2 values were soil organic carbon (SOC), 0.94; total nitrogen (TN), 0.96; and cation exchange capacity (CEC), 0.80. A spectral soil fertility index (SFI) was developed based on ten commonly used agronomic indicators of soil fertility. SFI varied significantly with current and historic land use. The index was successfully calibrated to both soil reflectance measured in the laboratory ( p =0.003) and Landsat TM reflectance ( p =0.003), which permitted mapping of the index.
Forfattere
An Tran Thi ThienSammendrag
Introduksjonen og dagens utbredelse for fem polyfage og invaderende minerfluearter i Vietnam blir behandlet. Noe informasjon om deres vertplantevalg og livssyklus blir også presentert.
Sammendrag
Søtkirsebærknoppar på bukettgreiner og skot vart undersøkt for smitte av Colletotrichum acutatum før knoppsprett i 4 sesongar. Både knoppar frå greiner som var smitta med C. acutatum året før og naturleg infiserte knoppar vart undersøkt. Soppen sporulerte på knoppane med små oransje hornliknande strukturar. Frå naturleg infiserte greiner var det frå 2 til 80% knoppar med sporulering på bukettgreiner og 0 til 53% på knoppar frå skot. Tilsvarande på knoppar frå greiner smitta året før var 38 til 79% på bukettgreiner og 4 til 45% på skot. På bukettgreinene som har både generative og vegetative knoppar var det mest sporulering på dei generative. Slike infeksjonar på knoppar er truleg ei viktig kjelde til smitte av C. acutatum om våren.
Forfattere
Brita ToppeSammendrag
Opprydning i rosebedet før vinteren bidrar til neste års blomsterprakt. Spesielt viktig er det å rense for å hindre utvikling av rosestråleflekk. Soppen overvintrer på bladverk og greiner og vil raskt spre seg om våren om den får være i fred.
Forfattere
Leiv Mortensen Brita Toppe H.R. GislerødSammendrag
The influence of high CO2 concentrations and diurnal variation in air temperature on the development of powdery mildew (Podosphaera pannosa) was studied in different cut rose cultivars grown under 20 h day"1 supplementary lighting. An increase in CO2 concentration from 380 to 1000, or 2000 "mol mol"1, did not affect development of the disease in cvs. `Escimo" and `Red Champ". Compared to constant temperature, a temperature drop from 22 °C to 16 °C over the course of 8 h significantly enhanced the attack of powdery mildew in both cultivars, while the same drop in temperature over the course of 4 h had no effect. In another experiment, a temperature increase from 20 °C to 26 °C reduced the attack of powdery mildew in the four cultivars studied (`Escimo", `Red Champ", `Jade" and `Cezanne") when applied over 4 h and even more so when applied over 8 h. Number of days until flowering was unaffected by CO2 concentration, but was increased by a drop in temperature and decreased by a rise. Fresh weight per shoot was increased by CO2 enrichment, a drop in temperature and by a 4 h period of increased temperature. The results are discussed in relation to an optimal greenhouse climate with respect to rose production and powdery mildew control.
Forfattere
Tor J. JohansenSammendrag
De første sikre opplysninger om potetdyrking i Nord-Norge er fra 1760-1770. Men først utover 1800-tallet ble poteten utbredt hos "almuen" og fikk betydning i kostholdet. Noen av de tidligste sortene var det vi i dag kaller Gammel Svensk Rød, Rød Kvæfjord, Lang Svenske, Blåpotet/Svartpotet og Rød Mandel. Utover 1900-tallet gjorde vanlig Mandel og Gullauge sitt inntog og er de eneste av gammelsortene som dyrkes kommersielt i dag.
Sammendrag
Transient starch production is thought to exert a strong control over plant growth and response to elevated CO2. Here we tested this hypothesis with an experimentally-based mechanistic model in Arabidopsis thaliana. " Experiments were conducted on wild type (WT) of A. thaliana, starch-excess and starchless mutants under ambient- and elevated-CO2 conditions to determine parameters and validate the model. Central to the model, we experimentally demonstrated that dark respiration is directly proportional to soluble sugar concentration in A. thaliana leaves. " The model correctly predicted that: 1) mutant growth is about 20% of that of WT, and 2) absolute response of both mutants to elevated CO2 is an order of magnitude lower than that of the WT. " Our study demonstrates that effects of the diurnal starch cycle on growth can be captured by a fairly simple set of allocation equations. Our results further suggest that the maximum rate of leaf growth, and broadly the sink capacity, exert a strong control over the response to elevated CO2 of herbaceous plants such as A. thaliana.
Forfattere
Gunhild BørtnesSammendrag
Så langt ser det ut som det vil vera mogeleg å få fram frø i Norge av sortar i dei eittårige vekstrane sar og dill. For fleirårige kryddervokstrar vil dette også vera mogeleg for kryddersalvie og sitronmelisse. For bergmynte bør vi satsa på den som er tilpassa vårt klima.
Sammendrag
Winter conditions with seasonally frozen soils may have profound effects on soil structure and erodibility, and consequently for runoff and erosion. Such effects on aggregate stability are poorly documented for Nordic winter conditions. The purpose of this study was to quantify the effect of variable freeze-thaw cycles and soil moisture conditions on aggregate stability of three soils (silt, structured clay loam-clay A and levelled silty clay loam-clay B), which are representative of two erosion prone areas in southeastern Norway. A second purpose was to compare aggregate stabilities measured by the Norwegian standard procedure (rainfall simulator) and the more widely used wet-sieving procedure. Surface soil was sampled in autumn. Field moist soil was sieved into the fraction 1-4 mm and packed into cylinders. The water content of the soil was adjusted, corresponding to matric potentials of -0.75, -2 and -10 kPa. The soil cores were insulated and covered, and subjected to 0, 1, 3 or 6 freeze -thaw cycles: freezing at -15 °C for 24 h and thawing at 9 °C for 48 h. Aggregate stability was measured in a rainfall simulator (all soils) and a wet-sieving apparatus (silt and clay B). The rainfall stability of silt was found to be significantly lower than of clay A and clay B. Clay A and clay B had similar rainfall stabilities, even though it was expected that the artificially levelled clay B would have lower stability. Freezing and thawing decreased the rainfall stability of all soils, but the effect was more severe on the silt soil. There was no evident effect of water content on the stability, probably due to experimental limitations. The same effects were observed for wet-sieved soil, but the wet-sieving resulted in less aggregate breakdown than the rainfall simulator. Rainfall impact seemed to be more detrimental than wet-sieving on more unstable soil, that is, on silt soil and soil subjected to many freeze-thaw cycles. Such conditions are expected to occur frequently during field conditions in unstable winters.
Sammendrag
Trøndelag som destinasjon har ikke det spektakulære i seg som fjordene på Vestlandet, men kan likevel by på en spennende historie, et rikt kulturliv, levende landbruk og muligheter for naturopplevelser både ved kysten og i fjellet. Det å "se karakteristiske kulturlandskap" og det å "lære om andre mennesker og steder" betyr mye både for norske og utenlandske turister. Ved økt bevissthet og satsing på de ressursene kulturlandskapet kan tilby kulturturismen, bør landskapskvalitetene kunne opprettholdes og videreutvikles slik at de appellerer til reiselivsnæringa også i framtida.