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
Inger MartinussenSammendrag
Bær inneholder en rekke verdifulle stoffer og flere har påvist at ekstrakter av bær har en helsefremmende effekt. Samtidig er det studier som viser at de aktive stoffene i bærekstraktene er vanskelig for kroppen å ta opp gjennom fordøyelsessystemet. Det gjenstår derfor mye forskning for å forstå hvordan bær i dietten påvirker helsa vår. I tillegg til antioksidanter innholder bær en mengde ukjente molekyler som kan ha kommersiell betydning for framstilling av blant annet medisiner og kosmetikk.
Forfattere
Anette SundbyeSammendrag
Det finnes mange bladvepsarter, men de vanligste artene som gjør skade på løvtrær er lindebladveps (Caliroa annulipes) og fruktbladveps (Caliroa ceraci). Det kan også oppstå angrep av askebladveps (Tomostethus nigritus) og bladveps på bjørk (Arge pullata). Larvene eter på bladene og trærne får redusert prydverdi og kan dø dersom det blir gjentatte angrep flere år på rad, særlig i kombinasjon med tørke eller andre uheldige vekstforhold. Vi bør derfor forebygge angrep av bladveps og bekjempe evt. angrep med manuelle tiltak.
Forfattere
Hugh RileySammendrag
Relatively large declines in SOM have been found since 1952 at Kise Research Station and also since 1990 on many arable fields. There was little indication that SOM is now becoming stabilized. In both cases declines were greatest at high initial SOM levels. Several factors may have caused the declines, including more intensive tillage, lower use of leys and higher soil temperature. Two simple models suggest that soils with current SOM levels of 4%, 6% and 10%, respectively, may be expected to reach a possibly `critically" low level (3%) either in 80, 165 and 230 years (`one tenth" model) or in 30, 70 and 120 years (`fixed 1%" model).
Forfattere
Hugh RileySammendrag
Mineral- og husdyrgjødsel er undersøkt i et gjødslingsforsøk i sørøst Norge. Resultater av avlinger, næringsstoffbalanse og jordanalyser ble presentert, og det ble gitt en oversikt over andre undersøkelser som er utført de siste 10-15 årene i forbindelse med dette forsøket.
Forfattere
Hugh RileySammendrag
Endret (redusert) jordarbeiding påvirker både jordstrukturen og jordas moldinnhold. Ved slik praksis er halmrester på overflaten og fuktigere jordforhold med på å senke jordtemperaturen litt om våren, noe som trolig forsinker frigjøring av nitrogen fra jorda. Dessuten vil kanskje tettere jord øke N-tapet ved denitrifisering. På den annen side vil økt moldinnhold tilsi at N-frigjøring fra jorda økes noe på sikt, noe som kanskje vil redusere plantenes gjødslingsbehov. Som en konklusjon fra undersøkelsene på morenejord, kan vi si at endret jordarbeiding ikke ser ut til å påvirke plantenes generelle behov for N-gjødsel under forhold hvor man lykkes med et slikt system. I praksis vil det imidlertid ofte være slik at avlingsnivået ved redusert jordarbeiding begrenses av én eller flere faktorer (dårlig etablering, ugras osv.). I prinsippet vil dette redusere N-behovet noe, ut fra tankegangen om gjødsling etter forventet avlingsnivå. En viss økning i gjødselmengden vil imidlertid kompensere en del for nedsatt vekst ved f. eks. dårlig etablering. Dette kan trolig forsvares økonomisk , men ikke ut fra miljø- og ressurshensyn.
Forfattere
Hugh RileySammendrag
Factorial combinations of N, P and K fertilizer have been compared with the use of farmyard manure at Møystad since 1922 in a seven-year crop rotation (3 ley, oat, potato, wheat, barley). Until 1982, low inputs of N fertilizer (22 kg ha-1) were used. In 1983, they were brought into line with current farming practice. This paper presents results of three subsequent rotations. Yields without any fertilizer were on average 48% of those with 100 kg N ha-1 in compound fertilizer, whilst those with 20, 40 and 60 Mg ha-1 farmyard manure were 81, 87 and 90%, respectively. Yields with other combinations of N, P and K declined in the order NP, NK, N, PK and K. When NPK fertilizer was used, apparent recoveries of applied fertilizer were close to 50% for N and K, and around 40% for P. Much lower values were found for nutrients applied singly. Balance between N supply and removal was indicated at rates of about 60 kg N fertilizer ha-1 in potatoes, 75 kg ha-1 in cereals and 90 kg ha-1 in leys. A surplus of P was found in all crops at all N levels, and of K in cereals and potatoes. In leys, K balance was achieved with an N supply of 90 kg N ha-1. Nutrient balance was indicated at a little below 20 Mg ha-1 yr-1 farmyard manure. Larger manure applications gave large nutrient surpluses, particularly of N. Soil reaction remained close to neutral with the use of calcium nitrate and manure, but declined with the use of ammonium nitrate. Manure use gave the highest amounts of available P, K and Mg in soil. Similar increases in total inorganic P were found with manure use as with fertilizer use, but amounts of organic P and total K were little affected.
Sammendrag
Several models for prediction of infection periods for lettuce downy mildew (Bremia lactucae) are based on the assumption that spores are produced at night and released in the early morning. The divergent light conditions at Nordic latitudes might affect both sporulation and spore release. Therefore, during the period 2001 to 2005 a total of 13 field trials were established in late season lettuce fields to evaluate efficacy of fungicide applications made according to the models PlantPlus (PP) and Modell-Analys (MA) in Norway. Disease severity varied from 0 to 89.4 % in unsprayed control plots at harvest. Fungicide treatments had a significant effect compared to untreated control in all but two of the field trials with disease incidence over 1 % at harvest. Fungicide applications at 10-day intervals and according to PP and MA resulted in an average of 3, 2.5 and 3.3 applications, respectively. There were no significant differences in disease severity at harvest between treatments according to 10-day interval, PP and MA for any of the field trials. Epidemics were created at two field locations that had no previous lettuce production, and a total of 59 days of spore trapping permitted the study of spore release under natural conditions. Spore production events predicted by MA were correct at 66 % of the days. However, when adjusting the criteria for spore production, 78 % of the days were correctly predicted.
Sammendrag
Virulence characteristics of Bremia lactucae populations from lettuce crops in the southeast and southwest of Norway from 2001 to 2005 were studied in relation to virulence factors (v-factors) and virulence phenotypes (v-phenotypes). The frequencies of 19 v-factors were analysed, and phenotypic diversity was calculated in relation to v-factors and v-phenotypes. A total of 39 different v-phenotypes were identified from the 58 samples analysed. Four of these were identical with the previously denominated races Bl:17, 18, 22 and 24. The most commonly occurring v-factors were v1, v2, v4, v5/8, v6, v7, v10, v11, v12, v13 and v18. V-factor v17 was not present in any of the tested isolates and v36 was found only once. V-factor v38 was first seen in 2004, coinciding with the observations of broken resistance in many cultivars. The population of B. lactucae in Norway was diverse, but not considerably different from other European populations of this pathogen.
Sammendrag
The prediction of infection periods for lettuce downy mildew (Bremia lactucae) is based on the assumption that spores are produced at night and released in the early morning. The divergent light conditions at Nordic latitudes might affect both sporulation and spore release. Therefore, we monitored release of B. lactucae spores in relation to the climatic conditions in lettuce fields to evaluate the performance of existing forecasting models in timing of fungicide applications for management of lettuce downy mildew in Norway. In 2005, epidemics were created at two field locations that had no previous lettuce production, and a total of 59 days of spore trapping permitted the study of spore release under natural conditions. Sporulation events were compared to predicted spore production events in Modell-Analys (MA). At the two locations, 76 % and 74 % of the spores were trapped between 08.00 and 16.00, respectively. Spore concentration icreased with decreasing relative humidity (RH), ofting coinciding with increasing solar radiation and temperature. Spore production events predicted by MA were correct at 66 % of the days. However, when the criteria for spore production were adjusted, 78 % of the days were correctly predicted.
Forfattere
Berit Nordskog Bodil Jönsson Richard Meadow Sverre Kobro Håvard Eikemo Klaus Paaske Irmeli Markkula Arne Hermansen Guro BrodalSammendrag
Models for prediction of diseases and pests in fruits and vegetables are important tools in the decision of crop management strategies. In the Nordic countries several models are currently available for the farmers and extension services on the Internet. The most widespread pests and diseases which are forecasted and/or monitored include apple scab (Venturia inaquealis) and apple fruit moth (Argyresthia conjugella) in apples, cabbage root fly (Delia brassicae) and turnip root fly (D. floralis) in Brassica vegetables, carrot root fly (Psila rosea) in carrots, and downy mildews in lettuce (Bremia lactucae) and onion (Peronospora destructor).