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.
2006
Sammendrag
Environment Synthesis) family of crop models predicts cereal growth, development, and yield. CERES simulates nitrogen (N) as a yield"limiting macronutrient. Because N leaching is an economic and environmental concern, this study evaluated if CERES can be used to predict N leaching under different N management scenarios: background leaching in unfertilized corn (Zea mays L.), alfalfa (Medicago sativa L.) residue mineralization, and till versus no"till management. Data were collected during a 7"yr field experiment on tillage practices in a maize"alfalfa"maize succession. Sensitivity analyses were performed for decomposition rates of the different residue pools and the relative proportions of carbohydrate, cellulose, and lignin in the residues. During the last 5 yr, under corn, CERES accurately simulated nitrate leaching from the no"till lysimeters. Nitrate leaching was underestimated in the tillage treatments, possibly because CERES does not simulate tillage. The model is not very sensitive to the decomposition rates and to the composition of the residues
Forfattere
Helge Bonesmo Stein Rune Karlsen Anne Kjersti Bakken Kjell-Arild HøgdaSammendrag
Seasonal growth and minimum and maximum N content of timothy swards were calculated on the basis of soil and weather data for five sites and five years in Norway. The five sites covered a wide range of the climatic variation among regions with agricultural grass production. For each of the sites and years the daily estimated grass growth was related to the Normalized Difference Vegetation Index (NDVI) obtained from the MODIS satellite data, and on pixel-by-pixel basis threshold values of the NDVI for grass growth cessation was assessed. On the basis of the threshold values a colour map of the whole country was made, where different colours symbolized altogether four time intervals for suggested/simulated growth cessation of local timothy swards. Finally, minimum and maximum N uptake of timothy swards in the period close to growth cessation was calculated as a basis for the recommendation of local final dates of surface application of cattle slurry.
Forfattere
Anne Kjersti Bakken Helge Bonesmo Tor Lunnan Olav HarboSammendrag
With the overall aim of improving the phenological function of a decision support tool support for predictions of grass yield and fodder quality , we have tested how appropriately the scale Mean stage by count describes the continuum of phenological events in timothy. Further adaptions to the presented equations describing the functional relationships between temperature and development are suggested.
Sammendrag
Effects of composting on survival and reproduction of the potato cyst nematode (PCN) Globodera rostochiensis were investigated in 150-liter pilot scale reactors. Small bags containing cysts of PCN were incubated in organic waste and composted for 8, 15 or 29 days. Temperatures in the areas close to the cyst bags were monitored. Survival, measured by hatching, was reduced by 99.9% already after 8 days of composting and at 29 days no hatching was recorded. A few eggs, however, still hatched after being composted for 15 days and exposed to temperatures higher than 60°C for several days. Maximal temperatures and thermal exposure time as such could not explain the hatching pattern of PCN, so other factors are likely to be involved in causing lethality. PCN failed to reproduce after 8 days of composting with temperatures reaching a minimum of 50°C during the period. Hence, eight days of composting where all material have reached a temperature of minimum 50°C during the period, could be regarded as a satisfactory method for sanitation of PCN.
Sammendrag
Et nærmere 2 meter høyt sperregjerde ble i april satt opp mellom første og andreårsfelt to steder i Norge (Kise og Ørlandet). Hensikten var å se om dette kunne hindre billene i det eldre feltet å komme inn i det nye. Tidligere år har vi prøvd inngjerding av mindre ruter i åkeren med svært godt resultat, men vi ville nå prøve et enklere og mer realistisk opplegg. Billene ble ikke helt stengt ute fra førsteårsfeltet med denne metoden, slik at det også ble skade der, men den var mindre enn forventet. Vi må studere billens atferd for å komme videre med gjerdemetoden (kommer f.eks billene inn i nyplantede felt allerede om høsten?), og dette vil vi gjøre i det nye prosjektet "Kontroll av snutebiller i jordbær ved hjelp av luktstoffer og andre alternative metoder".
Forfattere
Daniel Rasse Marie-France Dignac Bahri Haithem Cornelia Rumpel Mariotti Andre Claire ChenuSammendrag
Lignin har lenge vært antatt å være en viktig kilde for karbon i jord på grunn av sin lite nedbrytbare polyfenol-struktur i forhold til andre grupper organisk materiale. Studier av omsetning av lignin har imidlertid vist motstridende resultater og de fleste tyder på at en stor del av lignin fra planterester brytes ned i løpet av ett år etter innblanding i jord. Vi har her foreslått en to-pool modell hvor lignin i ferskt plantemateriale (Lp) enten kan opptre delvis beskyttet i jord mot videre nedbryting (Ls) eller blir omdannet til ikke-lignin produkter. Data til kalibrering av modellen ble skaffet ved hjelp av isotopanalyse av lignin spesifikk 13C fra en serie med 0-9 års ensidig maisdyrking etter hvete på en lettleire i Frankrike. Lignin ble kvantifisert ved CuO-oksidasjon som VSC-lignin, det vil si som summen av fenoltypene vanillil (V), syringyl (S) og coumaryl (C). Kalibreringene indikerte at Lp har en omsetningshastighet raskere enn ett år og at 92 % ble mineralisert til CO2 eller omdannet til andre ikke lignin-produkter, mens bare 8 % tilhørte Ls-fraksjonen. Estimert omsetningshastighet av Ls-fraksjonen var 0,05 år-1. Modellen tydet også på at om lag halvparten av Lp ikke var målt fordi det var blitt fjerne gjennom siktingen av prøven (5 mm). Som konklusjon, modellen tydet på at kjemisk bertandighet ikke er tilstrekkelig alene til å forklare omsetningen av VSC-lignin i jord, og at den mest relevante mekanismen funksjonelt synes å være overgang av VSC-ligning molekyler og fragmenter fra nedbrutt plantevev til jord-beskyttede fraksjoner.
Forfattere
Stein Harald HjeltnesSammendrag
Artikkelen gir ein introduksjon til rotekte plommesortar i Noreg. Under inventering i nokre få område, er det funne ulike typar av gule, raude, blå og grøne plommer. Ein del av desse er skildra i norsk pomologisk litteratur, og dei er også skildra i annan skandinavisk litteratur. Det er lite att av slike plommetre i dei fleste fruktdyrkingsområde.
Forfattere
Ricardo Holgado Janet Rowe Stig Andersson Christer MagnussonSammendrag
Cereal cyst nematodes, Heterodera spp., are recognised throughout the world as economically important parasites of cereals. The virulence status on cereal cultivars differs between and within different species of the H. avenae-complex, and several pathotypes occur among them. A survey during 1995-2005 in Norway revealed that Heterodera spp. is common throughout the country. Studies in Norway have recorded H. filipjevi and also additional and possibly new species. A number of cereal cyst nematode populations from various regions of Norway, Sweden and the British Isles have been analysed using molecular, morphological and host range studies during the last three years. Fifteen populations, of the initial group of forty, are being studied more closely. Studies using isoelectric focusing and silver staining have detected divergent populations of H. avenae. The Swedish populations Ringsåsen seemed to be identical to a population found in Australia and the Swedish population Halland shows a protein profile separate from H. avenae. DNA studies are being used to determine if these populations are new species. An assortment of cereal cultivars, based on an international collection used for resistance testing, differentiates three groups, H. avenae (pathotypes Ha 11 and Ha 12), H. filipjevi (pathotype "West"), and a population from central Norway close to H. pratensis. Knowledge of the diversity of cereal cyst nematodes and their multiplication rates on their cereal hosts is of fundamental importance for efficient control strategies involving resistant cultivars. In Norway, management based on these parameters are in operation and have increased yields and profits to cereal farmers.
Sammendrag
The aim of this three-year study (2001"2003) was to optimize fungicide application against anthracnose (Colletotrichum acutatum) in sweet and sour cherry orchards. The experimental sprays were applied to trees receiving normal fungicide programmes (grower schedule), although without the use of dithianon, except for the first year where only the experimental applications were applied to the sour cherry trees. Fungicide treatments were applied with either dithianon or copperoxychloride added prior to flowering or with dithianon added after flowering. Spraying with dithianon or copperoxychloride prior to flowering did not significantly reduce anthracnose compared to untreated. Two applications with dithianon during the green fruit stage (from petal fall and during the following 3"4 weeks) greatly reduced anthracnose at harvest. Three applications on green fruit did not reduce disease more than two applications. In sweet cherries, two sprays with dithianon at the green fruit stage in addition to the grower schedule reduced anthracnose at harvest from 14% to 3% in 2002 and from 15% to 1% the following year. In 2001, when very few fruit developed anthracnose, no treatment effects were evident. Treatments on green sour cherry fruit similar to those on sweet cherries reduced the attack of anthracnose from 85% to 42% in 2002 and from 51% to 12% the following year. In 2001, no treatment included only sprays on green fruit. However, one treatment, which included copperoxychloride at bud burst, one application of dithianon during flowering and two applications on green fruits, reduced anthracnose from 27% to 9%. Based on these results, cherry growers are recommended to spray twice with dithianon on green fruit if they have a history of anthracnose in their orchards.
Sammendrag
Temporal changes in the scores of selected soil fertility indices were studied over six years in three different cases of organic crop rotation located in southern, eastern and central Norway. The cropping history and the initial scores of fertility indices prior to conversion to organic cropping differed between the sites. Crop yields, regarded as an overall, integrating fertility indicator, were in all rotations highly variable with few consistent temporal trends following the first year after conversion. On the site in eastern Norway, where conversion followed several years of all-arable crop rotations, earthworm number and biomass and soil physical properties improved, whereas the system was apparently degrading with regard to P and K trade balances and contents in soil. On the other two sites, the picture was less clear. On the southern site, which had a relatively fertile soil before conversion, the contents of soil organic matter and K decreased during the six-year period, but the scores of other fertility indices showed no trends. On the site in central Norway, there were positive trends for earthworm-related indices such as worm biomass and tubular biopores, and negative trends for soil porosity. The results, especially those from the eastern site, illustrate the general difficulty in drawing concllusions about overall fertility or sustainability when partial indicators show divergent trends. Consequently, the study gave no unambiguous support to the initial working hypothesis that organic farming increases inherent overall soil fertility, but rather showed that the effect varied among indicators and depended on status of the cases at conversion. It is concluded that indicators are probably better used as tools to learn about and improve system components than as absolute measures of sustainability.