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.
2001
Sammendrag
Due to the climate the yields of roughage in Northern Norway are considerably lower and more variable than in other parts of the country. The problems relate to severe winter damage on meadows caused by snow, ice carpet and low temperatures. A linear programming model representing an average milk farm of the province has been worked out to study the farm economy of different short-term measures. The model is based on farm accounts in the area and calculates the farm profit in the price level and support regime of the year 2000. The model crop yields are based on field research trials in area. The study shows that the production problems can be overcome by increasing the purchase of feed and by adding extra labour and costs to repair the meadow. The profitability of the farm is worsened. However, governmental support for restoring the area as well as extra support to buying additional roughage compensate for the extra cost unless more than 50 percent of the meadow have to be restored. Hiring more land may be profitable while advanced slaughtering of animals is unprofitable unless family labour input can be reduced due to higher opportunity values. Farm profit can be improved if cheap roughage can be purchased or own production of roughage can be increased by improving the farm crop yield level.
Forfattere
G.H. Ludvigsen Olav LodeSammendrag
In this paper the results from 12 locations concerning streams and rivers are presented from the years 1995-1999. During this period 851 samples have been collected giving the result that 63% contained pesticide residues. Of a number of 53 substances have 33 pesticides been detected in surface water.Of these, 21 were herbicides, 8 fungicides and 5 insecticides. A number og 13 different pesticides were detected in concentrations, supposed to have environmental impact on algae, daphnia or other aquatic species. The different pesticides showed very different pattern according to the frequency and concentrations that were measured.
Forfattere
Gunnar Ogner Guro Randem Torild WickstrømSammendrag
Analyses of forest soils are widely used to monitor the effects of human activity on our environment. The overall quality of analytical data must, therefore, be sufficient to answer questions with regard to environmental changes taking place throughout several decades.Three horizons of an air-dried forest soil, was stored at 22 3 C, 3 C and 21 C for up to 1842 d to monitor its stability during storage. At room temperature, soil acidity increased and soil pH in water decreased by 0.1 to 0.3 pH units depending upon the soil horizon.The amount of C, P, and S extracted by 1M ammonium nitrate increased by 94%, 62% and 68%, respectively, after 1842 d. A corresponding increase in exchangeable cations [aluminium(Al), barium(Ba), calcium (Ca), magnesium (Mg), manganese (Mn), strontium (Sr), and zinc (Zn)] ranged from 11 to 23%. Storage at 3 C resulted in a decrease in pH only for mineral soil (10-15 cm layer). At 21 C, no changes in any of the soil-extractable components were found.
Forfattere
Nina Heiberg Arnfinn NesSammendrag
Bringebær til friskkonsum dyrkes i økende grad i plasttunneler i England. Plasttunnelene brukes både for å beskytte bærene mot klimaskader samt til å forskyve modningstidspunkt. Ved dyrking i plasttunell modner bærene 3-4 uker før enn på friland. Ved sein utplanting av ettårige planter med lange skudd forskyves modningen utover høsten. Flere dyrkingsteknikker er beskrevet i artikkelen.
Sammendrag
Ein har stor nytte av å skjerme mot vind. Til og med svak vind kan redusera og gjere skader på avlingane i jord- og hagebruk. Om ein etablerer lé kan ein rekne med avlingsauke på 5 - 20%. Minst like viktig er truleg at kvaliteten på produkta vert betre og avlinga kan haustast tidlegare. Et prosjekt i Møre og Romsdal viser at gode lébelte vil kunne etablerast om ein vel dei rette artene og opphava til buskar og trer.
Forfattere
Aksel GranhusSammendrag
The risk of logging damage to residual trees (height >3.0 m) and advance regeneration saplings (height 0.5–3.0 m) was evaluated after mechanized (single-grip harvesters + forwarders) and motor-manual (chain saw + skidding) selection harvesting in studies I and II. Harvesting took place during the winter season. Mechanized harvesting caused the highest injury rates, and the difference was highest at high cutting intensity in densely stocked stands. Another important difference between the two operating methods was the spatial distribution of the injury risk relative to striproads. The most important injuries on the larger (>3.0 m) trees were stem- and root wounds, and loss of branches. Wounds tended to be larger, and crown injuries more serious, after mechanized harvesting, but differences were not statistically significant. The most frequent injuries on saplings were crown injuries (loss of branches, stem breakage) and stem lean. In motor-manually harvested stands saplings without pre-harvest deformities in the form of top- or leader defects were more prone to damage than saplings with such defects. A similar difference was not found in stands subjected to mechanized harvesting. This result was attributed to the different work patterns during felling and processing with the two operating methods, in combination with the spatial distribution of saplings of different quality relative to larger trees and stand openings. In study III sapling mortality, and recovery from logging damage in a five-year period after selection harvesting, was investigated. Mortality on the different plots (n=11) was highly variable. For saplings without previous logging damage mortality was related to pre-harvest vigour, and increased with increasing cutting intensity in the immediate surrounding of the sapling. Unspecified site factors also contributed to explain the probability of mortality. Saplings that had been pushed over during harvesting often survived and recovered, while injuries to the crown led to poor survival. Crown injuries were most common on plots subjected to mechanized harvesting, while stem lean was correspondingly important on motor-manually harvested plots. Whether this pattern was attributed to differences in temperature at the time of harvesting (winter), or operating method, is uncertain. In study IV advance regeneration responses in terms of height growth, needle dry weights, and foliar nutrient concentrations were compared after three different release treatments: untouched control, selection harvesting with 50-60 % removal of basal area (BA50-60), and patch cut (25x25 m - 0.063 ha clear-cut). The foliar analyses were carried out five years after treatment, and included dominant and co-dominant (overstorey) trees on control and BA50-60 plots. Height growth and needle dry weights of saplings generally increased with increasing overstorey removal. The growth response was explained by an interaction of foliar nitrogen concentration in current (C) and one-year-old (C+1) needles, and degree of overstorey removal. The foliar analyses did, however, not confirm improved N status after cutting. Increasing overstorey removal led to a reduction of K (C), Mg (C+1) and B (C, C+1) in saplings. A parallel decline of B (C+1) occurred in the overstorey trees (BA50-60). Saplings on control plots had higher concentrations of K and Cu in C-needles, relative to overstorey trees. The influence of neighbour tree basal area on sapling height growth and presence of natural defects (top- and leader damage) was examined in study V. The three stands selected for the study had not been subjected to cutting for several decades, and basal areas ranged from 25–33 m2 ha-1. The relationship between growth and four basal area variables was evaluated: basal area (m2 ha-1) of taller (>3.0 m) neighbour trees within 2.82, 3.99 and 5.64 m radius from the sapling (25, 50 and 100 m2 circular plots), and basal area (m2) of trees within 5.64 m radius weighted according to distance from the sapling. A reduction of growth attributed to increasing basal area of neighbour trees was only observed for the tallest saplings (2.1-3.0 m). Between 33 and 42 % of the saplings had leader- or top defects, and damage frequencies increased with declining distance to the nearest taller neighbour tree.
Forfattere
Mekjell Meland Magne Eivind Moe Eivind Vangdal Z. PutnamSammendrag
Kompost frå våtorganisk avfall omdanna i reaktor har vorte prøvd i ulike mengder og mogningsgrader i feltforsøk og som vekstmedium til karplanter i åra 1999 og 2000. Fersk kompost i trerekkjene nytta som dekkemiddel i frukthagar var spirehemmande på frøugraset første året. Nitrogen vart frigjort og teke opp av trea. Mogen kompost som tilskot i jorda ved planting av prydtre og innblanding ved etablering av plen hadde positiv verknad på tilveksten. Innblanding av 7,5 og 15 tonn pr. daa med fersk og mogen kompost i jorda hemma ikkje oppspiringa av gras. Særleg fersk kompost i mengdetilhøve 25 og 50 % i blanding med veksttorv hemma tilveksten sterkt av både plommetre, jordbærplanter og blåkorg i karforsøk. Den negative verknaden av kompost i vekstmedia kan rettast opp med gjødsling og bruk av mogen kompost.
Sammendrag
Tørråte har vært fraværende på Island i mange år, men var vanlig forekommende i 1990 og 1991. Sjukdommen ble ikke observert i 1992-1998. I 1999 ble det igjen funnet tørråteangrep. Blader med tørråte ble sendt til Planteforsk Plantevernet som isolerte soppen og gjennomførte tester av krysningstype og metalaksylsensitivitet. En av 15 undersøkte isolater var A2, de resterende var A1. Metalaksylresistens ble også påvist. Undersøkelsen viser at den "nye" tørråtepopulasjonen også er tilstede på Island.
Forfattere
Geir Isak Vestøl Olav Albert Høibø Thea H. Slotnæs Kjetil VærnesSammendrag
Hensikten med arbeidet var å dokumentere egenskapene til trelast med store dimensjoner fra grov gran på Vestlandet. Årringbredde, tørrdensitet, densitet ved 12% fuktighet, elastisitetsmodul og skjærmodul ved statisk bøying og statisk bøyefasthet ble registrert på 89 planker med dimensjon 75x250 mm og 39 planker med dimensjon 100x350 mm. Materialet stammet fra to bestand av gran plantet i Kvam og i Granvin, og ett bestand av naturlig gran i Voss. Prøvetrærne ble tatt ut blant de medherskende trærne på alle tre feltene og blant de dominerende trærne på feltene i Voss og Kvam. Fra de med-herskende trærne ble det tatt ut to margplanker med dimensjon 75x250 mm. Resultatene viste bl.a. at forskjellene i bøyefasthet, elastisitetsmodul og tørrdensitet mellom materialene fra Kvam og fra Voss var små til tross for at det var betydelig lavere årringbredde i materialet fra Voss. Variasjonene i skjærmodul var store og tilfeldige og var bare i liten grad knyttet til de andre egenskapene. Ved sortering etter NS-INSTA 142 ble nedre 5% fraktil av bøyefastheten til kvalitetsklasse T3 undervurdert, mens nedre 5% fraktil av bøyefastheten til kvalitets-klasse T2 var som forventet. Den relativt store forskjellen i egenskapene til trelasten fra de dominerende og fra de medherskende trærne viser imidlertid at tynningen vil være avgjørende for utviklingen av egenskapene til trelasten. Ved å satse på de medherskende trærne fremfor de dominerende vil man over tid kunne oppnå gode egenskaper på enda større dimensjoner enn det man kan i dag.
Forfattere
Malin Elfstrand Carl Gunnar Fossdal Gunilla Swedjemark David Clapham Olof Olsson Folke Sitbon Praveen Sharma Anders Lönneborg Sara von ArnoldSammendrag
In this study we have investigated whether the defensin-like gene spi 1, isolated from Norway spruce, contributes to quantitative disease resistance and is a suitable candidate for utilisation in Norway spruce breeding programmes. The following questions have been raised: (1) Can the putative defense gene, spi 1, improve the defense towards microbial pathogens in a model plant species, tobacco? (2) Is it possible to produce transgenic plants of Norway spruce that overexpress spi 1 and are less susceptible to the pathogenic fungus Heterobasidion annosum? Compared to control plants, tobacco plants expressing spi 1 under an enhanced CaMV 35S promoter permitted less growth of the bacterial pathogen Erwinia carotovora. Embryogenic cultures of Norway spruce were transformed with a similar construct. The general phenotype of regenerated transgenic plants was normal, although it was difficult to maintain certain sublines in culture owing to poor initial growth. Among the transformed plants those with the highest content of SPI 1 displayed reduced fungal growth in the sapwood after inoculation with H. annosum. In conclusion, the spi 1 gene increases resistance in both homologous and heterologous systems.