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
Sammendrag
Dette er den tredje og siste artikkelen i ein serie artiklar om soppsjukdomar på gran i SKOGeieren. Fokus i denne artikkelen er på soppsjukdomar som fyrst og fremst gjer skade på litt eldre grantre.
Forfattere
L.E. Sverdrup Thomas Hartnik E. Mariussen J. JensenSammendrag
Halogenated flame retardants have a high sorption affinity to particles, making soils and sediments important sinks. Here, three of the most commonly used flame retardants have been tested for sub-lethal toxicity towards soil nitrifying bacteria, a terrestrial plant (seed emergence and growth of the red clover, Trifolium pratense), and a soil invertebrate (survival and reproduction of Enchytraeus crypticus). Tetrabromobisphenol A (TBBPA) was quite toxic to enchytraeids, with significant effects on reproduction detected already at the 10 mg kg1 exposure level (EC10 = 2.7 mg kg1). In contrast, decabromodiphenyl ether (DeBDE) was not toxic at all, and short-chain chloroparaffins (CP10"13) only affected soil nitrifying bacteria at the highest test concentration (EC10 = 570 mg kg1). Exposure concentrations were verified by chemical analysis for TBBPA and DeBDE, but not for CP10"13, as a reliable method was not available. Based on the generated data, a PNEC for soil organisms can be estimated at 0.3 mg kg1 for TBBPA and 57 mg kg1 for short-chain chloroparaffins. No PNEC could be estimated for DeBDE. Measurements of TBBPA in soil are not available, but measured concentrations in Swedish sludge are all lower than the estimated threshold value for biological effects in soil.
Forfattere
Tor Gunnar Vågen Markus G Walsh Keith D. ShepherdSammendrag
The impacts of human land use in the highlands of Madagascar are often equated with land degradation and decreasing soil fertility. The practice most often focused on is deforestation through slash-and-burn cultivation (tavy), and shifting cultivators are often portrayed as being ignorant, poverty-stricken peasants felling trees for fields and food. However, there is uncertainty whether soil degradation is related to recent tavy or earlier forest clearance, and whether some highland areas were ever forested. In this paper we use stable isotopes (!13C) and diffuse reflectance spectroscopy (DRS) to study the impacts of deforestation and various other land use changes on ecosystem properties, soil organic carbon (SOC) dynamics and soil quality (fertility) in the highlands of Madagascar. Land cover transitions (between C3 and C4 systems) are defined and quantified in the study area. Historical land use had greater effect on soil organic carbon concentrations than current land use, with cultivated areas previously under C3 and C4 systems having 37.3 and 14.8 g SOC kg"1, respectively. Grasslands previously under C3 had approximately 124% more SOC than grasslands previously under C4, while SOC concentrations were 65.3 and 54.9 g C kg"1 under natural forest and in mixed fallow systems, respectively. A soil fertility index developed for the study area based on diagnostic soil spectra was compared with findings related to SOC dynamics and land use change.
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.