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.
2007
Forfattere
Arnstein Staverløkk May-Guri Saethre Eline Benestad HågvarSammendrag
The invasive ladybird, Harmonia axyridis Pallas 1773, is recorded for the first time in Norway. The specimen was found on horticultural plants imported from Aalsmeer in the Netherlands to Oslo, Norway. H. axyridis originates from East-Asia. The species is known to be a voracious predator on aphids and has been extensively used as a biological control agent in both North America and Europe. The later years, however, a number of negative impacts on the environment and biodiversity have been reported. The species was assessed as a potential bio-control agent for use in Norwegian greenhouses in 2001. The outcome of the assessment was negative with respect to import and commercial use in Norway. It was concluded that H. axyridis might survive and become established outdoors and thereby pose a risk to the environment. Recent experiences from the UK have shown that H. axyridis compasses several of the traits characterizing a successful invasive alien species. The record of this species in Norway may only be the first in a number of such, as it is likely that this species will survive outdoors, at least in the southern parts of Norway.
Forfattere
Nina Opstad Arnfinn Nes Finn Måge Bjørn HagebergSammendrag
Two-year-old blackcurrant plants cv. Ben Tron were planted in 1991 to investigate long-term effects of seven fertilization strategies. Broadcast fertilization was given in spring and autumn, fertigation from May until August, or a combination of fertigation and broadcast fertilization. Three fertilizer rates were used, and the amount was increased three times during the trial because of low mineral content in the leaves and insignificant yield response. Yield parameters, macro nutrient content in leaves and content of soluble solids in fruit juice were recorded over 11 years. The variation between years was significant for all parameters recorded, but the fertilization strategies had only a minor effect over time. Content of macro nutrients in leaves was low compared to recommended values, and did not respond significantly to increasing fertilizer amounts. Yield decreased with plant age. Frost reduced yield in at least two years, but few significant correlations with precipitation and temperature were found. A good water access seems to be important for a stable fruit yield, while precipitation during flowering is likely to reduce yield because of fruit drop.
Forfattere
Ketil Haarstad Gro Hege LudvigsenSammendrag
Pesticides in Norwegian ground water have been monitored since 1995. Here we report data including 2004. The monitoring has focused on shallow groundwater near agricultural fields (4 locations), farm wells (22 locations) and on public water works (38 locations), 450 samples were analyzed for a total of 62 pesticide compounds and metabolites, and the result was 514 detections of single compounds. Altogether 27 pesticides and metabolites were detected; 2 insecticides, 9 fungicides and 16 herbicides. Herbicides were most frequently detected (in 79% of the samples), followed by fungicides (20%) and insecticides (1%). Pesticide concentration was generally low, although high concentrations also occurred, for example 33 "g/l of metribuzine in shallow ground water near agricultural fields, and 20 "g/l of bentazon in a farm well. Some water soluble pesticides occurred both frequently and with relatively high concentrations in shallow ground water near agricultural fields. The results show that local ground water near farms is vulnerable for contamination of pesticides and needs further monitoring. Efforts should be made to minimize contamination of wells in farming areas through education on pesticide use, monitoring and well positioning. Few pesticides were detected in ground water from water works and the concentrations were low. Monitoring of water works ended in 2002. The data show that there is a continuous need to monitor pesticides as well as selected metabolites in shallow ground water and wells near agricultural fields in Norway.
Sammendrag
Sigevann fra Bangarvågen deponi er vist å inneholde høye konsentrasjoner av bl.a. polysykliske aromatiske hydrokarboner (PAH), benzen, toluen, etylbenzen og xylen (BTEX) og hydrokarboner (HC). Bioforsk Jord og miljø ble kontaktet av Norconsult for å teste adsorpsjon og nedbrytning av organiske forurensninger i ulike filtermaterialer ved bruk av kolonnetester. Hensikten med forsøkene var å komme fram til bindningskapasitetene til de ulike jordblandingene under forhold som etterlignet en rensevoll i Bangarvågen. Ulike prøver av sand, mineraljord, myrjord og kompost ble vurdert brukt som filtermaterialer etter måling av kornfordeling og en visuell vurdering av prøvene. Åtte 40 cm høyde og ø 10 cm stålkolonner ble deretter pakket med 0-2 mm maskinsand tilsatt torv i økende volumprosent fra 0, 12,5 til 30 %. I tillegg til effekten av organisk materiale ble effekten av gjødsling med nitrogen og fosfor og lufting av sigevannet undersøkt. Sigevann ble pumpet motstrøms gjennom kolonnene (mettet vannstrøm). Eluater fra kolonnetestene ble analysert for tungmetaller og organiske forbindelser og rensegrad og filterkapasitet ble estimert. Forsøksresultatene gav følgende konklusjoner: 1) 10 volumprosent torvjord må tilsettes til maskinsand 0-2 mm for å oppnå nødvendig sorpsjon av metaller og organiske stoffer; 2) det er ikke nødvendig å gjødsle eller lufte sigevannet for å oppnå tilstrekkelig rensing av sigevannet i barrieren; 3) BTEX ble funnet å være den organiske forurensningen som krever størst filtertykkelse.
Forfattere
Miguel D. Mahecha Markus Reichstein Holger Lange Nuño Carvalhais T. Grünwald Dario Papale G. SeufertSammendrag
Characterizing ecosystem-atmosphere interactions in terms of carbon and water exchange on different time scales is considered a major challenge in terrestrial biogeochemical cycle research. The respective time series currently comprise an observation period of up to one decade. In this study, we explored whether the observation period is already sufficient to detect cross-relationships between the variables beyond the annual cycle, as they are expected from comparable studies in climatology. We investigated the potential of Singular System Analysis (SSA) to extract arbitrary kinds of oscillatory patterns. The method is completely data adaptive and performs an effective signal to noise separation. We found that most observations (Net Ecosystem Exchange, NEE, Gross Primary Productivity, GPP, Ecosystem Respiration, Reco, Vapor Pressure Deficit, VPD, Latent Heat, LE, Sensible Heat, H, Wind Speed, u, and Precipitation, P) were influenced significantly by low-frequency components (interannual variability). Furthermore, we extracted a set of nontrivial relationships and found clear seasonal hysteresis effects except for the interrelation of NEE with Global Radiation (Rg). SSA provides a new tool for the investigation of these phenomena explicitly on different time scales. Furthermore, we showed that SSA has great potential for eddy covariance data processing, since it can be applied as a novel gap filling approach relying on the temporal correlation structure of the time series structure only.
Forfattere
Mekjell Meland Magne MoeSammendrag
The performance of the plum rootstocks Marianna, Pixy and Wangenheim using St. Julien A as a standard to the cultivars `Avalon", `Edda", `Excalibur", `Jubileum", `Reeves" and `Victoria" was assessed in a field trial in western Norway at 60" North. Trees were planted in spring 1999, the plant material was one-year-old whips, spaced 2.0 x 4.5 m and formed with a central leader as free spindles. Soil management was grass in the alleyways and herbicide strips 1-m wide along the tree rows. Tree vigour, yield, fruit size and yield efficentcy were evaluated for the six subsequent years. Tree size was significantly affected by the rootstocks after six years growth. Wangenheim produced the smallest and St. Julien A and Pixy the largest trees as measured by trunk cross-sectional area in average for the different cultivars. St. Julien A and Pixy were the most productive rootstocks for the cultivars. However, Pixy produced significant larger yields per tree to the cultivar `Reeves" than St. Julien A. Trees on Pixy were the most yield efficient for all cultivars with the exception of `Victoria". The fruit sizes were in general large for all cultivars and became little affected by the different rootstocks. Fruit quality characterized by the content of soluble solids was in general high and did not differ between trees on the various rootstocks. The cultivar `Avalon" had the highest contents of soluble solids.
Sammendrag
To avoid problems with seed borne diseases in organic cereal production, seed health testing should be compulsory in certification of organic seed. In general, significantly lower infection frequencies of seed borne diseases are recorded on seedlings than on seed. Thresholds for the amount of seed borne inoculum that can be accepted for organic production are therefore needed. The aim of the work presented is to compare transmission rates of Drechslera on barley and oats under organic and conventional conditions, to be able to decide if existing thresholds used to assess the need of chemical seed treatment, can be applied for acceptance of organic seed lots, or for recommendation of alternative treatments. Field experiments were carried out in 2005 in conventional and organic fields situated close to each other at each of three locations (south/east-Norway, east-Norway and mid-Norway). 10 seed lots of barley and 10 lots of oats, with a range of seed infections (barley: 0-94 % Drechslera teres, average 31.4 %; oats: 0-66 % Drechslera avenae, average 22.0 %) were planted in rows of 100 seeds with 8 replicates in each location/`growing system". Percent emergence and seedlings with primary infections were recorded at BBCH 12-13. On average in the three locations 2.5 % and 1.8 % barley seedlings were infected when grown in conventional and organic fields, respectively. In oats, 2.0 % and 0.9 % infected seedlings were recorded in conventional and organic fields, respectively. Similar experiments will be carried out in 2006 and results from this will also be presented.
Forfattere
Klaus MittenzweiSammendrag
De internasjonale matvareprisene for korn og meieriprodukter har økt betydelig i den senere tid. Om økningen vil være varig avhenger av flere faktorer, deriblant økonomisk vekst i Asia og dreining av forbruksmønster i den regionen mot vestlige matvaner. Dersom dette skulle bli en realitet, er det muligheter for at de internasjonale matvareprisene vil legge seg på et høyere nivå sammenlignet med situasjonen i perioden 2000-2005. For norsk jordbruk kan dette bety et økt handlingsrom til å utforme nasjonal landbrukspolitikk. I lys av de pågående WTO-forhandlingene om en ytterligere liberalisering av handelen med matvarer, innebærer dette at de forventede effekter av tollreduksjoner motvirkes av høyere importpriser. For å vurdere det økte handlingsrommet er det gjennomført kvantitative beregninger med den partielle likevektsmodellen Jordmod. Modellen omfatter mesteparten av dagens jordbruk og beregner et aktivitetsnivå (dvs. først og fremst innenlandsk produksjon og innsats av areal og arbeidskraft) i norsk jordbruk ut i fra de rammebetingelsene (importpriser, støttenivå og bruksstruktur) som legges til grunn i de enkelte scenariene. Grunnet modellens natur er resultatene alene ikke et tilstrekkelig grunnlag for en samlet vurdering av de scenariene som er utformet i denne analysen. Modellresultatene må derfor tolkes med forsiktighet og suppleres med annen kunnskap om konsekvensene av en ny WTO-avtale for norsk jordbruk. I en samlet vurdering tyder analysen på at en videreføring av viktige trender i dagens jordbrukspolitikk vil fortsatt kreve en aktiv tilpasning av norsk landbrukspolitikk. I en slik situasjon vil den relative betydningen av en eventuell ny WTO-avtale basert på Falconers forslag til avtale fra juli 2007 blir mindre. Falconer er formann i WTOs jordbrukskomité. Økte verdensmarkedspriser alene kan innebære at den totale støtten til norsk jordbruk kan reduseres uten at dette vil gå utover bøndenes inntekter. Med en ny WTO-avtale på plass vil det være et ytterliggere innsparingspotensialet. Økte verdensmarkedspriser kan gi høyere matvarepriser innenlands. Den samlede samfunnsøkonomiske effekten av høyere konsumutgifter for matvarer og en reduksjon i støtten til norsk jordbruk vil trolig likevel være positiv.
Sammendrag
In parts of the world, Se availability in the soil is so low that Se contents in the crops produced there are well below recommended values. Since the difference between Se essentiality and toxicity is very small, the addition of Se via fertiliser is controversial. Therefore, it is important to utilise the Se added in the best possible way. The objective of the present study was to investigate the influence of soil organic matter on the one hand, and addition of organic material (slurry) on the other hand on plant availability of selenium (Se) in soil. Pot experiments with the Se addition in the form of selenate were conducted with a peat, a loam and a peat/loam mixture at a range of pH values between 5 and 6.8. Se uptake from added Se fertiliser was higher in the soil types with high organic matter content than in the loam at pH 6 and below. The opposite occurred at a soil pH above 6.4, where Se uptake was higher in the loam than in the peat. In a pot experiment using only peat and loam at two pH levels, cattle slurry added together with selenate was found to increase the Se concentration in grain at the higher pH. At the lower pH there was no significant effect of slurry on Se concentration in grain. Application of slurry also increased the residual effect of Se that had been applied to the loam in the preceding growing season. In the peat, no residual effect of Se was found either with or without the addition of slurry.
Sammendrag
Det er umulig å forutsi om en vil få angrep av soppsjukdommer om vinteren, og hvor sterke angrepene eventuelt vil bli. En soppbekjempelse om høsten er derfor en forsikring. Behovet må vurderes etter hvor stor risikoen for angrep er. I den vurderinga må en ta hensyn til hvor stor risikoen for langvarig snødekke er på skiftet, hvor store plantene er ved innvintring, halmbehandling m.m. Hvis angrepene blir kraftig vil normalt et storbilurinholdig preparat være best, mens det ved moderate angrep er små forskjell mellom det godkjente midlene. En behandling koster rundt 40 " 50 kr, og forventet avlingsgevinst bør derfor være rundt 25 kg for å dekke direkte utgifter.