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.
2008
Forfattere
Celine Rebours Jim Treasurer Richard Fitzgerald Julie Maguire Nina Zhuravleva Oddvar OttesenSammendrag
Biological control of sea lice with wrasse is considered an alternative to medicines and can form part of an integrated sea lice management plan (Mordue and Pike, 2002). While wrasse have been used previously in sea lice control there have been reservations about fishing the wrasse from wild stocks with possible erosion of local stocks and changes in population structure (Sayer, Gibson and Atkinson, 1996; Varian, Deady and Fives, 1996). An EU Northern Periphery Project entitled "Ecofish" has been established to examine the rearing of ballan wrasse Labrus bergylta and the application of this species in sea lice control. This species has been shown to be a successful cleaner of sea lice in preliminary trials and may be more suitable than smaller wrasse with larger second production year salmon.
Sammendrag
This study compares diversity an abundance of spiders in barley with different sub crops and in young ley. Spiders were sampled from 14 cereal and 4 grass-clover fields distributed within three different sites in eastern and central Norway. Two sites were long term experimental field trials and one was an organically managed farm. Pitfall traps were used to sample spiders from May to Sept 2004. In total 4130 spiders were found. The density and number of species varied between fields. More individuals of both Linyphiidae and Lycosidae were trapped in fields with leys compared to fields with cereals. There was no clear difference in total density of spiders according to type of sub-crop, but more Lycosidae were found in cereal fields undersown with ley than in fields undersown with ryegrass. A higher density of Linyphiidae was found in the cereal fields at the farm than at the two experimental sites, whereas the frequency of Lycosidae was about the same at the three sites. Only minor differences in number of species were found, but an ordination technique of multivariate analysis reveals differences in the spider community structures.
Sammendrag
Increasing levels of Fusarium toxins, particularly deoxynivalenol (DON), T-2 /HT-2 and moniliformin, have been recorded in Norwegian cereals during the last few years. Previously F. avenaceum, F. culmorum, F. poae and F. tricinctum were the most common Fusarium species found on cereals in Norway. However, more recently F. graminearum has occurred more frequently, and the T-2/HT-2 toxin producing species F. langsethiae has also been detected, especially in oats. Investigations were made to clarify if there has been a change in the composition of Fusarium species. We are aiming to establish a three-step screening system in order to identify grain lots with high levels of Fusarium toxins: 1- Identify `high-risk" fields/lots, based on information on cultivation practice and climatic conditions, through the use of a FHB-prediction model. 2- Analyze the `high-risk" lots using a rapid test selected for its capacity to detect Fusarium toxins in a large number of grain samples at low cost. 3- Forward selected samples (based on analyses in step 2) for chemical mycotoxin analyses. Since 2004, we have run chemical mycotoxin analyses on grain samples from oat and spring wheat grown in Norway under different climatic conditions. Prediction models will be developed to estimate the risk of Fusarium infection and mycotoxin development in cereal fields, based on data for weather and cultivation practices. Preliminary results from using the prediction models will be presented.
Forfattere
Bent J. Nielsen Jens Grønbech Hansen Hans Pinnschmidt Ragnhild Nærstad Arne Hermansen Vinh Hong Le Asko HannukkalaSammendrag
The existing potato late blight forecast and decision support systems used in the Nordic countries are based on data from the 1930s and the 1950-60s on how temperature and humidity influence Phytophthora infestans epidemiology. Influence of weather conditions on sporangium production, release, viability and infection of P. infestans was investigated in Denmark, Norway and Finland using Burkard spore traps and exposure of trap plants in field plots in 2005-2007. Large amounts of sporangia were trapped after nights with long periods with high humidity. Sporangia produced in one humidity period were mainly released at the first humidity drop in the morning hours, but there were also some periods with delayed sporangium release. Local new infections occurred mainly during the morning hours when leaves were still wet. On many days sporangia did not survive until the afternoon and the results indicate that conditions for survival of sporangia and infection are major bottlenecks for the spread and development of the disease. These results have important implications for practice. Survival of sporangia and infection must be better integrated into the calculation of "risky days" in late blight forecasting systems.
Forfattere
Ragnhild Nærstad Arne Hermansen Vinh Hong Le Bent J. Nielsen Jens Grønbech Hansen Hans Pinnschmidt Asko HannukkalaSammendrag
The existing potato late blight forecast and decision support systems used in the Nordic countries are based on data from the 1930s and the 1950-60s on how temperature and humidity influence Phytophthora infestans epidemiology. Influence of weather conditions on sporangium production, release, viability and infection of P. infestans was investigated in Denmark, Norway and Finland using Burkard spore traps and exposure of trap plants in field plots in 2005-2007. Large amounts of sporangia were trapped after nights with long periods with high humidity. Sporangia produced in one humidity period were mainly released at the first humidity drop in the morning hours, but there were also some periods with delayed sporangium release. Local new infections occurred mainly during the morning hours when leaves were still wet. On many days sporangia did not survive until the afternoon and the results indicate that conditions for survival of sporangia and infection are major bottlenecks for the spread and development of the disease. These results have important implications for practice. Survival of sporangia and infection must be better integrated into the calculation of "risky days" in late blight forecasting systems.
Forfattere
Kristin DaugstadSammendrag
Det blir sagt at før fans det to slag potet i Valdres. Det var svarteplo og (kvit)eplo. Kvar det har vorte av det kvite slaget veit me ikkje. Men den svarte blir fortsatt dyrka i Valdres, men mest som hobby. Skalet på poteten er nærast plommefarga med lyse spetter i. Formen er rundoval og noko ujamn med relativt djupe grohol. Når me skjer over poteten ser me at det omtrent 1 cm frå skalet er ein fiolett ring. Fargestoffet er anthocyanin, same stoffet som ein finn i blåbær. Svart Valdres gir god avling , men den lir av det same som dei fleste eldre sortar som til dømes Mandel: den er svak mot sjukdom og spesielt turrote. Dei siste åra har etterspørsel en etter fleire av dei gamle potetslaga auka. Mandelpotet er svak mot sjukdom og gir låge avlingar, men på grunn av den store etterspørselen og omdømmet som gourmetpotet, kan produsentane få ein brukbar pris. Gullauge frå Nord-Norge og Ringerikspotet er andre gamle lokale spesialsortar. Med rett marknadsføring skulle det ikkje vere noko i vegen for å lansere Svart Valdres som Valdres sin eigen gourmetpotet. Så får me håpe nokon har tid og interesse for å dyrke denne poteten.
Forfattere
Anne Falk Øgaard Anne-Kristin LøesSammendrag
In organic cereal production, restrictions on use of mineral fertilizers will in many cases reduce the P concentration in soil, and short term leys and catch crops will contribute to decrease the risk of P losses due to reduced erosion. However, the current means to control perennial weeds increase the risk of soil erosion and P loss. On organic farms with ruminants, the aim of self-sufficiency with fodder will often cause a low P-surplus, or even a P deficit on the farm level. This will reduce the P content in soil and thereby the P loss to the environment. However, if organic farming develops to include more intensive production systems with high animal densities and purchased fodder, such systems will be prone to the same risks of high P surplus and P losses as conventional farming systems. Outdoor housing for animal welfare is likely to further increase these risks, and environmental concerns such as reducing P losses from agriculture should be considered when organic farming systems are further developed.
Forfattere
Håvard SteinshamnSammendrag
Grassland legumes are essential in organic ruminant livestock production due to their ability to fix atmospheric nitrogen (N), providing high yields of high feeding value without N fertilization. White clover (Trifolium repens L.) and red clover (Trifolium pratense L.) are the most important legumes of temperate grasslands with white clover as the most widely used. New research has reviled new properties of red clover that may affect animal performance and product quality significantly. Red clover containing diets have increased the production of milk and meat (compared with grasses) and the content of beneficial fatty acids in milk and meat (compared with grasses and other legumes), improved the efficiency of feed N utilization (compared with Medicago sativa L.), and increased the milk content of isoflavones (compared with grass and white clover). Red clover contains high levels of the enzyme polyphenol oxidase that might reduce the extent of lipolysis and proteolysis. The paper presents a review on resent results from own and others" research on the use of red clover in the diet of ruminants and the likely mechanisms by which red clover affects production and product quality
Sammendrag
A characterisation of the hydrological behaviour of four small agricultural catchments in Estonia and Norway was carried out using a flashiness index (FI). FI reflects the frequency and rapidity of short term changes in runoff values. A comparison of FIs based on hourly and average daily discharge indicated large within-day variations over very short time intervals. Large differences were observed between the Norwegian and Estonian catchments, irrespective of whether average daily discharge or hourly discharge values were used. A comparison of the FI and the base flow index (BFI) showed that high FI values corresponded to low BFI values. Norwegian catchments with high FI or low BFI values showed high nutrient losses, whereas the contrary was observed for the Estonian catchments. Although the FI does not a priori give information about the flow processes within catchments, we believe that the FI, as well as the BFI, might be helpful in explaining differences in nutrient and soil losses between catchments.
Sammendrag
Healthy seed is important for a successful plant production and organic cereal production must rely on management of seed-borne diseases without synthetic seed treatment chemicals. Inoculum thresholds, i.e. the level of seed borne inoculum that can be accepted, are needed for organic cereal production. In general, significantly lower infection frequencies of seed borne diseases are recorded on seedlings than on seed. The aim of the work presented was to compare transmission of Drechslera teres from barley seeds to seedlings in soils with different content of organic materials. Experiments with two seed lots (93 % and 94 % D. teres, respectively) have been carried out in greenhouse with 8 different soils collected in different cereal growing regions. 100 seeds with 3 replicates from each seed lot were planted in each soil type and placed for emergence at 12 oC. Percent emergence and percentage seedlings with symptoms of net blotch were recorded at BBCH 10-12. The net blotch frequency as average for the two seed lots ranged from 11 to 21 % in the different soils. Higher content of organic materials resulted in less infection frequencies. A correlation was found between the amount of organic materials in the soil and % net blotch (r = -0.83, P = 0.009). Experiments will be repeated with less infected seed lots