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
Six cropping systems, ranging from conventional arable without livestock to organic livestock farming with few arable crops, have been compared since 1989 on a loam soil. Soil structure indicators measured initially included organic matter levels, pore size distribution and air permeability. These parameters were re-measured after 15 years, when the size distribution and stability of aggregates was also measured. A decline in soil structure quality was found in the system with conventional autumn ploughing with no rotational grass. This system had higher bulk density and mean aggregate size than other systems, and lower levels of plant available water and aggregate stability. Opposite trends were related to the proportion of grass leys in the other systems and to their levels of soil organic matter. The latter declined markedly over 15 years in the conventional arable system, and there were smaller declines in most other systems. In an arable system without ploughing, organic matter was maintained and high structural stability was found. This system had high bulk density, but the proportion of small aggregates equalled that found in the systems with ley. Satisfactory soil structure was maintained in systems with 50% leys in the rotation, in agreement with Norwegian long-term studies of the effect of crop rotation type on soil organic matter. Though the deterioration of soil structure in the all-arable system was not extreme, as the soil had good structure initially, the results have serious implications for the sustainability of stockless arable systems on soils with a less favourable starting point.
Forfattere
Tor Einar Rogne Jørgen Todnem Tor LunnanSammendrag
Det er utført gjødslingsforsøk på fem stølsvollar i Sør-Norge (720-1040 m.o.h.). To haustesystem, ei eller to haustingar vart prøvd saman med fem gjødslingar: Ugjødsla, 1,5 kg fosfor (P= + 10 kg kalium (K) og P + K med tillegg av 5, 10 eller 15 kg nitrogen (N)/daa. Felta er hausta i fire år. I tillegg til avling og fôrkvalitet er førekomsten av karplanter registrert kvart år. Artstalet pr. rute (0,4 m2 registrert) varierte frå 9 til 18 planteslag på ugjødsla ruter mellom felta. Det var statistisk sikker nedgang i artstal med stigande gjødsling på dei to mest artsrike felta. Konkurransesvake artar gjekk ut, og på eitt av felta vart finnskjegg konkurrert ut av engkvein. Gjødslinga auka avlinga med frå i middel 180 kg tørrstoff på ugjødsla ruter til 470 kg ved den sterkaste N-gjødslinga. Proteininnhaldet og askeinnhaldet auka med stigande gjødsling. Det var små utslag av hausteintensitet på botanisk samansetjing og avling, men fôrkvaliteten var best ved to haustingar.
Forfattere
Trygve S. AamlidSammendrag
I denne artikkelen i det svenske tidsskriftet "Greenbladet" summereres de viktigste resultater fra prosjektet "Berigolf - benefits and environmental risks of fungicide applications on Scandinavian golf greens". Prosjektet har vist at strobilurinene azoxystrobin og trifloksystobin mer effektive enn andre soppmidler når det gjelder bekjempelse av både overvintringssopp og de fleste sopper som forkommer i vekstsesongen. Ved gjentatt bruk er det imidlertid fare for at begge disse soppmidlene kan utvikle resistens, og de bør derfor ikke brukes mer enn to ganger i året. For å redusere faren for resistensutvikling blir i Norge begge preparat markedsført sammen med propikonazole under navnene henholdsvis Amistar Duo og Stratego. I Sverige er bare den reine formen Amistar (uten andre aktive komponenter enn azoksystobin ) godkjent. Sammenlikna med trifloksystobin har azoksystobin lengre halvveringstid og bindes mye mindre til det organiske materialet og i jorda. Amistar / Amistar Duo er derfor mindre miljøvennlig enn Stratego og bør derfor ikke brukes på reine sandgreener uten organisk materiale i vekstmediet.
Forfattere
Trygve S. AamlidSammendrag
From 2003 to 2006, three varieties of velvet bentgrass (Agrostis canina), thirteen varieties of creeping bentgrass, nine varieties of colonial bentgrass (Agrostis capillaris), four varieties of slender creeping red fescue (Festuca rubra var. trichophylla), thirteen varieties of chewings fescue (Festuca rubra var. commutata), and one variety of annual bluegrass (Poa annua var. reptans) were evaluated for establishment rate, overall turf quality (visual merit), tiller density, color, leaf fineness, per cent living plant cover, winter injury, disease resistance, spring green-up, daily height growth, and thatch accumulation in trials on USGA-spec. putting greens at the Bioforsk research stations Landvik (58°N, 12 m a.s.l.) and Apelsvoll (61°N, 250 m a.s.l.) in south-east Norway. These experimental sites are considered representative for the southern/coastal and the northern/ continental zone of Scandinavia, respectively. The trials were mowed three times per week to 3 mm for bentgrass species and annual bluegrass and to 4.5-5.0 mm for red fescues, fertilized with easily soluble, small-grain mineral fertilizer every second week, and otherwise managed as putting greens with respect to irrigation, vertical mowing, topdressing etc. The greens were not open to regular play, but articifial wear was imposed by rolling friction-drums with golf-spikes over the trials three timers per week. On average for varieties within each species, velvet bentgrass had the highest visual merit scores at both experimental sites. Velvet bentgrass had higher density and finer leaves than any other species in the study. Along with colonial bentgrass, it also had better winter survival than creeping bentgrass, red fescue and annual bluegrass. The main disadvantage of velvet bentgrass is the rapid formation of thatch; this problem must be resolved before a general recommendation for use of velvet bentgrass on Scandinavian putting greens can be given. Next to velvet bentgrass, colonial bentgrass and creeping bentgrass were ranked as the most suitable species for golf courses in the northern/continental and southern/coastal zone, respectively. Red fescues should be preferred on golf courses not using fungicides and with limited maintenance budgets. While annual bluegrass `True Putt" cannot be recommended for putting greens in any part of Scandinavia, the ranking of varieties within each species depended, for the most part, on climatic zone. The following list of recommended varieties for putting greens has been presented to the Scandinavian Turfgrass and Environment Research Foundation:
Sammendrag
Chemical recalcitrance of specific molecules is one of the factors governing organic matter stabilization in soils. Little is known about the relationship between the chemical nature and the dynamics of soil organic matter at the long-term scale. Lignin molecules are abundant in plant tissues and are generally considered as slowly biodegradable in soils. In a previous study, using compound specific isotopic tracer techniques applied to agricultural lands converted from C3 to C4 cropping, we showed that lignin turnover was faster than that of total organic carbon. Lignin dynamics was well described by a two-pool model, distinguishing lignins in fresh plant residues and those more closely associated to the soil matrix. These two pools may be transformed into non-lignin products, which includes CO2, microbial biomass and chemical substances, which are no longer recognized as lignin derivatives. The aim of the present work was to study the nature and dynamics of these non lignin products formed during lignin degradation in a laboratory incubation of 13C-labelled lignin with soil. Maize plants were grown for 1 month under 13C enriched CO2. The lignins of leaves and stems were isolated after treatment with cellulolytic enzymes and solubilization in dioxane:water (1:9). The Milled Maize Lignin (MML) obtained had a 13C abundance of 1.4 %. Solid-state 13C NMR spectroscopy of MML before analysis showed that the isolation method produces a lignin-cellulose complex, as indicated by the presence of some polysaccharides (the 60-115 ppm region represented about 40 % of total C of isolated lignins). Lignins were incubated with soil (1 mg lignin/g soil) at 20°C in sealed glass jars and analyzed after 1, 2, 4, 8, 16, 32 and 48 weeks. A control sample was incubated without lignin. We monitored the mineralization, solubilization and incorporation in the microbial biomass of lignin C by measuring 13C enrichments in respired CO2, water-soluble fractions, and fumigated biomass, respectively. Lignins remaining in incubated soils were quantified by CuO oxidation and the 13C contents of vanillyl, syringyl and cinnamyl units (VSC) were measured. After 4 months, 3% of the 13C of the labelled lignin was mineralized. This mineralization rate was less than that found by Martin and Haider (1979) for DHP lignins but more than the 5% per year found in situ by Dignac et al. (2005). Less than 0.5% of incubated lignin C was water soluble and 0.5 % was incorporated into the soil microbial biomass. The main part (96%) of incubated MML remained in soil. We used compound-specific isotopic analysis of the CuO oxidation products and pyrolysis analysis to estimate the proportion of intact lignins remaining in the soil.
Forfattere
B. M. Dahal B. K. Sitaula R. M. Bajracharya K. Atreya Alhaji JengSammendrag
Soil and nutrient losses are a major threat to farmland productivity in Nepal. Thus, soil and nutrient losses were monitored and analyzed from two and three crop patterns per year in Ansikhola watershed. Erosion was monitored from multi-terraced garicultural plots consisting of 2 to 3 terraces. The agricultural soil of the watershed was generally rich in terms of organic matter and nutrients (N, P, K). The nitrogen content of soil in leve lowland farm plots was higher in the 2 cropping plots compared to the 3 cropping plots. The soil pH ranged from 4.4 to 5.2 in both intensive and less intensive areas. Soil and nutrient losses were comparitively higher from intensively cropped areas; however, overall losses were less than average losses in other similar watersheds in Nepal.
Forfattere
Abdelhameed Elameen Solveig Haukeland Christer Magnusson Sonja Klemsdal May Bente BrurbergSammendrag
The pine wood nematode, Bursaphelenchus xylophilus, which is indigenous to North America, was introduced to Asia in the early 1900 and now causes severe damage to susceptible pine species in Japan, China, Korea and Taiwan. B. xylophilus was included in the A1 list of quarantine organisms by EPPO (European Plant Protection Organization) in 1985. B. xylophilus was reported for the first time in Europe in Portugal in 1999. There are more than 50 described species within the genus Bursaphelenchus worldwide, that are associated with coniferous and deciduous trees and spread by insect vectors. Within this genus is a group of morphologically very similar species; B. xylophilus, B. mucronatus, B. fraudulentus, B. kolymensis, B. conicaudatus and B. luxuriosae. This group of species is often referred to as the "B. xylophilus group". Due to the morphological similarity of the species, identification of Bursaphelenchus species in the B. xylophilus group is difficult. The common method of molecular identification for separating species within the B. xylophilus group is the use of ITS-RFLP (Hoyer et al. 1998). We have developed a multiplex polymerase chain reaction (PCR) method with specific primers, and the primers amplified product were 740, 340 and 300 bp for B. xylophilus, B. fraudulentus and B. mucronatus respectively. No cross reactions on the three studied species were observed. In contrast to the previously described PCR-RFLP method, this new method allows detection not only on pure isolates, but also on crude nematode suspensions from wood samples, and it could be very useful for quarantine purposes. References Hoyer U, Burgermeister W, Braasch H 1998 Identification of Bursaphelenchus species (Nematoda, Aphelenchoididae) on the basis of amplified ribosomal DNA (ITS-RFLP). Nachrichtenbl. Deut. Pflanzenschutzd. 50:273-27. Mota M M, Braasch H, Bravo M A, Penas A C, Burgermeister W, Metge K, and Sousa E 1999. First report of Bursaphelenchus xylophilus in Portugal and in Europe. Nematology 1:727-734. Smith, I. M. 1985. Pests and disease problems in European forests. FAO Plant Prot. Bull. 33:159-164. Yi C, Park J, and Chang K 1989. Occurrence of pinewood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and its vector, Monochamus alternatus Hope, in Korea. Pages 183-193 in: Proc. IUFRO Reg. Workshop For. Insect Pests and Tree Dis. in NE Asia. For. Prod. Res. Inst., Tsukuba, Japan.
Sammendrag
Jordbærplanta har en vekst- og utviklingsrytme som er nøye kontrollert av og synkronisert med de ytre klimatiske miljøforholda, særlig temperatur og daglengde (Heide, 1977), og dette fører til at denne rytmen er sterkt årstidsbundet i naturen. Vegetativ vekst så vel som blomstring og vinterkvile er nøye regulert av disse miljøfaktorene. Forståelsen av dette er viktig blant annet for å kunne utvikle jordbærproduksjon utenom vanlig sesong.
Sammendrag
Growth cessation and dormancy development in autumn are important adaptive responses of plants for survival in cold climates. This requires the timely sensing and transduction of a seasonal environmental signal, which for most species, including strawberry, is the decreasing daylength of autumn. However, in strawberry plants the dormant state is only quantitative and can be considered a state of semidormancy. Thus, the so-called dormant plants developing under prolonged short day (SD) conditions in autumn retain the capability for growth, albeit at a reduced rate. Dormancy and flowering responses of the strawberry cultivars Korona and Elsanta were studied in controlled environments. Plants were exposed to short day for 5 weeks at temperatures ranging from 9 to 27°C, and subsequently forced at short and long day at 18ºC. Effects on leaf and inflorescence growth and runner formation were recorded. Results from these and further experiments with prolonged short day exposure at temperature of 6 and 15ºC, will be presented and discussed.
Sammendrag
Myrjord dekker 2-3 % av verdens landareal og inneholder ca en tredel av jordas lager av organisk karbon og omtrent like mye carbon som i atmosfæren. Drenering og dyrking av myr fører til en mineralisering av organisk materiale. Denne artikkelen omhandler emisjon av drivhusgasser fra dyrket myr i Nord-Norge. CO2-emisjonen økte med temperaturen, mens tilsvarende effekt ikke kunne påvises for N2O- og CH4-emisjonen. Estimert netto emisjon av drivhusgasser fra rør-grøftet myr var ca 2,2 kg for CO2, 0,03 kg for CH4 og 0,13 kg for N2O, uttrykt i CO2-ekvivalenter. Netto C-tap var ca 0,6 kg C per m2 og år. Karbontap kan derfor betraktes som jordforringelse når en tar hensyn til klimagassemisjonen. Resultatene viste betydningen av CO2-emisjonen fra dyrket myr i nord, som var ca 17 ganger høyere enn N2O-emisjonen som CO2-ekvivalenter.