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.
2005
Sammendrag
Søtkirsebærproduksjonen i Sør-Afrika er prega av pioner-ånd. Dyrkarane satsar stort, men har mange utfordingar slik som klimatiske avgrensingar, redusert tilgang på rett plantemateriale og plantevern-rådgjerder, og dei manglar både offentleg støtta forskings- og utviklingsprogram og rådgjeving. Økonomisk er dette likevel interessant, sidan det vert betalt gode prisar for søtkirsebær i ein periode med lite utbod av denne vara.
Forfattere
Tor Håkon SivertsenSammendrag
In spring 2004 it was started a pilot project for determining the lengths of the periods of leaf wetness duration in apple orchards in a small region of commercial fruit growing in the county of Telemark in Southern Norway. In this area it is placed four automated meteorological stations (hourly values). The measurement of precipitation is made by two weather radars in pixel areas of 1x1km. In this pilot project the periods of leaf wetness duration is calculated at the 15 sites ( 15 orchards) using hourly measurements from the automated stations and the two weather radars. The quality of the measurements of precipitation from the weather radars is compared to rain gauge measurements of precipitation at the four automated stations. The concept of quality of meteorological measurements is shortly defined and discussed. Also the possibilities making the quality of the radar measurements better in the future is discussed.
Sammendrag
Adaptive traits in Picea abies (Norway spruce) progenies are influenced by the maternal temperatures during seed production. Here, we have extended these studies by testing the effects of maternal photoperiod and temperature on phenology and frost hardiness on progenies. Using eight phytotron rooms, seeds from three unrelated crosses were made in an environmental 2 x 2 factorial combination of long and short days and high and low temperatures. The progenies were then forced to cease growth rapidly at the end of the first growing season. An interactive memory effect was expressed the second growth season. Progenies from high temperature and short days, and from low temperatures and long days, started growth later in spring, ceased shoot growth later in summer, grew taller and were less frost hardy in the autumn than their full siblings from low temperatures and short days, and from high temperatures and long days. Norway spruce has developed a memory mechanism, regulating adaptive plasticity by photoperiod and temperature, which could counteract harmful effects of a rapidly changing climate.
Forfattere
Tore SkrøppaSammendrag
Det er ikke registrert sammendrag
Sammendrag
Semi- natural grasslands are the result of long term farming practices: they have been created and maintained by millennia of extensive low intensity land use, and their maintenance is completely dependent on human interference like mowing, grazing or burning. The long ecological histories of these formerly widespread habitats have often resulted in landscapes with a mosaic of patches, and a high biological diversity. In northern Europe, semi-natural meadows are among the most species-rich vegetation types with high diversity both at small- and large-scales as shown in examples from Central-Norway. The discontinuance or changes of traditional farming practices result in landscape changes and diminishing biodiversity as shown in examples also from Central-Norway. The traditional farming practices thus must be considered as a basic tool for development of correct management at each site when restoring and conserving biodiversity. To succeed, new mechanical and practical methods for maintaining semi-natural grasslands and their biodiversity must be based on knowledge of the ecological effects as former land-use practices.
Forfattere
Therese With Berge Haldor FykseSammendrag
Generelt er ugras hverken homogent eller tilfeldig fordelt i en åker, men klumpvis på en eller annen skale. Dette bør utnyttes til presisjonssprøyting (PS). En viktig hindring for gjennomføring av presisjonssprøyting mot frøugras i korn i dag er at gårdbrukeren ikke vet om ugrasmengden i området han kjører i, er over eller under skadeterskelen. En relativt enkel løsning er å montere et digital-kamera foran på traktoren, koble dette til PC med hurtige bildeanalyse-algoritmer og skadeterskler, og la PC"n styre åkersprøyta på/av automatisk. Ettersom dette kameraet vil fange opp et svært begrenset areal i forhold til hele sprøytebomsbredden, undersøkte vi hvor representativ informasjonen fra én telleramme på 0,25 m2 (simulert sprøytebredde). Tjue kornfelt a 192 tellerammer i 2001 og 2002 lagt i de viktigste korndistriktene i Norge ble analysert. Vi estimerte også hvor store areal som ikke ville blitt sprøyta ved PS, og dermed hvor mye herbicid korndyrkeren (og samfunnet) kunne spart med PS. Studien konkluderer med at én observasjon per bombredde, altså ett kamera, virker fornuftig, og at ca. 60 % av undersøkt kornareal var under skadeterskelen, og dermed unødvendig å sprøyte.
Sammendrag
Some high density sweet cherry orchards in Norway suffer from decay of trees resulting in death or reduced vigour of trees. A survey has been conducted monitoring healthy and infected trees from several orchards. The nutritional statuses of the soil and in the trees were in general in accordance with general accommodation. Different species of root nematodes were identified with levels above the damage of thresholds. Neither insects, diseases, bacterials nor virus were registered as the main reason for this dieback. However, differences between cultivars and rootstocks sensitivity were observed. In order to investigate this cherry tree decay further, new field trials were established in 2001 with trees of the cultivars Van and Kristin grafted on the two rootstocks Prunus avium seedling and Colt and trained as a central leader trees. Two parallel trials were planted; one in the soil of on old cherry orchard and the other in the soil from agricultural land where no fruit production has been conducted in advance. During the first years significant larger annual vegetative growth measured as trunk cross sectional area and annual shoot growth were registered from the trees growing in the agricultural soil. In the replanted cherry soil, trees grafted on the rootstock Colt grew more vigorously than the seedling rootstock based on leaf areas and shoot growth measurements. The first significant crop is expected in 2005.
Sammendrag
Disease incidence of non-abscised aborted and healthy sweet cherry fruits was investigated during two growing seasons. Fruits from two cultivars (`Van" and `Lapins") were assessed weekly during 4-6 weeks in June and July until 3-4 weeks prior to harvest. The fruits were either surface sterilized (in 0.5% NaOCl) or dipped in distilled water, both for 1 minute, prior to incubation at 20°C for 7 days in saturated air. Visible symptoms of fungal diseases were recorded at day 1, 2, 3, 4, and 7 after incubation. Aborted fruits had much higher disease incidence after incubation than healthy fruits. In 1999 the mean disease incidence was 56.3 and 15.8% in aborted and healthy fruits, respectively (`Van"). The following year, the mean disease incidence in `Van" was 63.0 and 1.4% in aborted and healthy fruits, respectively. Corresponding numbers for `Lapins" in 2000 were 80.6 and 9.0%. Surface sterilized fruits were less decayed than non-sterilized fruit, but differences were not significant. After incubation commenced, symptoms always appeared earlier in aborted compared to healthy fruits. The most frequently observed fungal pathogens were Monilinia laxa, Colletotrichum gloeosporioides, and Botrytis cinerea. A higher disease incidence and more rapid disease development in aborted fruits indicated that these were more vulnerable to fungal colonization than healthy fruits early in fruit development. Thus, non-abscised aborted fruits may act as important hosts of secondary inoculum for healthy fruits.
Sammendrag
Covering sweet cherry trees (Prunus avium L.) with plastic prior to harvest is used to prevent fruit cracking. The most commonly used covering system in Norway is a frame of wooden poles, which support a three-wire system. Removable plastic sheets lying as a flat roof above the trees are connected to the wires. Covering for 3 weeks prior to harvest reduced fungal fruit decay from 10 to 1% and from 50 to 10% in two years, respectively. Important fungal diseases causing fruit decay in Norway are brown rot, gray mold, bitter rot and Mucor rot. By covering the trees for five to six weeks prior to harvest (commercial practice is three to four weeks), one to two fungicide applications could be omitted. If the trees were covered all the time from flowering to harvest, all fungicide applications could be omitted without any increase in fruit decay. Extended periods of covering did not lower fruit quality. Sweet cherries are most susceptible to fruit decaying fungi during flowering and towards harvest. In a series of experiments, fruits were covered at those two periods and left uncovered during the less susceptible green fruit phase (ca. 5 weeks). Covering could replace fungicide sprays without any increase in fruit decay, but leaving out fungicide sprays on uncovered green fruits increased the amount of brown rot in three of four experiments. From numerous experiments we will conclude that use of rain protective cover is a powerful alternative to fungicide applications in sweet cherry.
Forfattere
Rolf Nestby Philip Lieten David Pivot Christiane Raynal Lacroix Massimo TagliaviniSammendrag
Dette sammendraget er basert delvis på hele artikler og delvis pa sammendrag av artikler. Tre av de 60 artiklene tar for seg totalopptak av elementer i jordbærplantens organer i to ulike dyrkingssystemer. Begge er antatatt å være optimale med hensyn på mengde og balanse mellom næringsstoffene. Virkningen på fruktkvalitet kan være dramatisk om nivået av et næringsstoff er utenfor dette området, men det kan også være virkninger initiert av forskjeller i optimålområdet. De fleste artiklene henviser til produktorientert kvalitet, men noen fokuserer på forbrukerorientert kvalitet, som diskutert av Shewfelt (1999). Diskusjonen her er på general basis, så en skal huske at det er forskjeller mellom sorter og at spesifkasjon av næringstilførsel ideelt sett bør vinkles mot behovet til en emkelt sort, eller en gruppe sorter som opptrer likt. Også, for å få en fullstendig forståelse av emnet skulle sammendraget ha omfavnet et større informasjonomfang om virkningen på planteutvikling av enkeltelementer, for eksempel av kalsium på fruktfasthet som spiller en betydningsfull rolle for strukturen i celleveggene. Imidlertid er intensjonen her å begrense informasjonen til resultater som peker på en direkte forbindelse mellom næringsopptak og fruktkvalitet.