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
Zhihui Yang Bal Ram Singh Sissel HansenSammendrag
Farmyard manure (FYM) and fertilizer applications are important management practices used to improve nutrient status and organic matter in soils and thus to increase crop productivity and carbon (C) sequestration. However, the long-term effects of fertilization on C, nitrogen (N) and sulfur (S) associated with aggregates, especially on S are not fully understood. We investigated the effects of more than 80 years of FYM (medium level of 40 Mg ka(-1) and high level of 60 Mg ka(-1)) and mineral fertilizer (NPKS and NK) on the concentrations and pools of C, N, and S and on their ratios in bulk soil, dry aggregates and water stable aggregates on an Aquic Eutrocryepts soil in South-eastern Norway. A high level of FYM and NPKS application increased the proportion of small dry aggregates (<0.6 mm) by 8%, compared with the control (without fertilizer). However, both medium and high level of FYM application increased the proportion of large water stable aggregates (>2 mm) compared with mineral fertilizer (NPKS and NK). The total C and N pools in bulk soils were also increased in FYM treatments but no such increase was seen with mineral fertilizer treatments. The increased total S pool was only found under high level of FYM application. Water stable macroaggregates (>2 and 1-2 mm) and microaggregates (<0. 106 mm) contained higher concentrations of C, N and S than the other aggregate sizes, but due to their abundance, medium size water stable aggregates (0.5-1 mm) contained higher total pools of all three elements. High level of FYM application increased the C concentration in water stable aggregates >2, 0.5-1 and <0. 106 mm, and increased the S concentration in most aggregates as compared with unfertilized soils. Higher ON, C/S and N/S ratios were found both in large dry aggregates (>20 and 6-20 mm) and in the smallest aggregates (<0.6 mm) than in other aggregate sizes. In water stable aggregates, the C/N ratio generally increased with decreasing aggregate size. However, macroaggregates (>2 mm) showed higher N/S ratios than microaggregates (<0. 106 mm). We can thus conclude, that long-term application of high amounts of FYM resulted in C, N and S accumulation in bulk soil, and C and S accumulation in most aggregates, but that the accumulation pattern was dependent on aggregate size and the element (C, N and S) considered.(C) 2007 Published by Elsevier B.V.
Forfattere
Zhihui Yang Bal Ram Singh Sissel Hansen Zhengyi Hu Hugh RileySammendrag
Understanding soil sulfur pools and associated aggregates S fractions can provide a platform for monitoring S dynamics in soils. A long-term experiment established in 1922 on an Aquic Eutrocryepts in South-eastern Norway was chosen to investigate the effects of long-term fertilization on S fractions in bulk soil and those associated with aggregates. Chloroform fumigation-extraction was used to determine Microbial biomass S (MBS) and the wet chemical analysis method was used to fractionate soil S into ester S (hydriodic acid reducible S), carbon-bonded S (Raney nickel reducible S) and residual S (Raney nickel non-reducible S). High farmyard manure (FYM) application resulted in higher MBS in bulk soil than nitrogen + potassium (NK) application, but it did not differ significantly from the control. Application of FYM at 60 Mg ha(-1) resulted into accumulation of total S, total organic S and carbon-bonded Sin bulk soils, while mineral fertilizer (nitrogen+phosphorus+potassium+sulfur [NPKS] and NK) and the medium rate of FYM did not increase the accumulation of total S and organic S fractions. The macroaggregate sizes (> 2 and 1-2 mm) and the finest aggregate size (< 0.106 mm) showed significantly greater total S concentration than other aggregate sizes. Ester S and residual S were predominant organic S fractions and they accounted for 39 to 52% and 38 to 51% of the organic S, respectively. The macroaggregate sizes (> 2 and 1-2 mm) contained the highest ester S, but microaggregates (< 0.106 mm) exhibited higher carbon-bonded S and residual S than other aggregates. In conclusion, the accumulation of S was dependent on fertilizer type, the rate of FYM application and aggregate sizes.
Sammendrag
Undersøkelser " Jord fra Møystad høsten 2003 " Effekt av ulik gjødsling gjennom 80 år på lagring av ulike svovelfraksjoner i jord " Effekt av størrelsen på jordaggregat på innhold av ulike svovelfraksjoner Resultat Mer enn 97% av S var organisk bundet. Gjødsling med 6tonn fast storfegjødsel per daa og år økte innholdet av total S, organisk bundet S og karbonbundet S i jorda, men ikke 4 tonn og ikke gjødsling med sulfatsvovel tilført gjennom mineralgjødsel (fullgjødsel). Størrelsen på jordaggregat påvirket forholdet mellom de ulike svovelfraksjonene i jorda.
Forfattere
Einar StrandSammendrag
Foredraget tok for seg rådgivning innen miljøspørsmål overfor jordbruket i Norge og presenterte norske regler og ordninger for redusere forurensing fra jordbruket.
Forfattere
Alhaji S. Jeng Roshan Bajracharya Bishal K. Sitaula Bed Mani Dahal Subodh ShermaSammendrag
Det er ikke registrert sammendrag
Forfattere
Alhaji Jeng Roshan Bajracharya Bishal Sitaula Bed Mani Dahal Subodh ShermaSammendrag
Agricultural intensification (AI) has for the past two or three decades been a widely practiced agricultural production system used in the mid-Hill watersheds of Central Nepal. This has been triggered by rising human and livestock populations which exert a serious pressure to the available agricultural land. The need to increase and secure agricultural output required greater use of agrochemicals (fertilizers and pesticides). The indiscriminate use of diverse types of pesticides and the exposure of farmers to these raised a number of questions relating to health, produce quality and environmental degradation. Kathmandu University in cooperation with Agricultural University of Norway and Jordforsk initiated a three year project in 2003 funded by the Norwegian Agency for International Development (NORAD) to, among others, provide: 1. A clearer understanding of the potentially adverse impacts of agriculture intensification in the mid-hills of Nepal; 2. Improved understanding of how market forces and external interventions may impact socio-economic development of rural communities and factors motivating farmers to adopt intensive production systems in the mid-hills; and 3. Useful policy formulation and implementation guidelines and tools for rapid assessment of land use and agricultural impacts of AI on soil and water quality and on environment and human health. LUKKET RAPPORT
Sammendrag
In the north-western European countries Norway, Sweden, United Kingdom (UK) and Ireland, variability in the forms, amounts and timing of phosphorus (P) loss from agricultural land is related to national differences in climate, soil, hydrological conditions and agricultural production. The dissolved form of P constitutes 9"93% of the total phosphorus (TP) in water, subsurface drainage can contribute 12"60% and surface erosion 40"88% of TP transfer. TP export in small agricultural streams is generally in the range 0.3"6 kg ha)1 year)1, with the highest losses in Norway and UK. All four countries are complying with the EU Water Framework Directive and developing a range of measures based on P source with transport controls over P losses. A decreasing trend in TP losses has been detected in agricultural streams following the introduction of measures to reduce erosion in Norway. Average P concentrations in Swedish streams have shown a reduction of nearly 2% per year since 1993 as a result of measures introduced in southern Sweden. However, in two large rivers in agricultural regions of Sweden, the concentrations of suspended solids (SS) and TP were shown to increase by 0.4% and 0.7% per year, respectively, over the period 1975"2004, possibly as a result of climate change. It is too early to detect trends in agricultural contributions to P in surface waters as a result of catchment-sensitive farming (CSF) in the UK and Ireland.
Forfattere
jihong liu clarkeSammendrag
Poinsettia (Euphorbia pulcherrima Willd. Ex Klotzsch), is a contemporary symbol of Christmas in most parts of the world. Today, Europe and North America represent the largest volume of production and sales, but demand is growing quickly in the Australian regions as poinsettia become popular each year (Williams 2005). In Norway, poinsettia is one of the most important pot plants with a yearly production close to 6 million plants. Its ornamental value and innovation potential has laid the foundation for an extensive research in Norway and elsewhere. Two viruses i.e. poinsettia mosaic virus (PnMV) and poinsettia cryptic virus (PnCV) can cause diseases on modern poinsettia cultivars. PnMV gives visible symptoms in poinsettia during parts of the growing season. Growers show great interest to the potential benefits of growing PnMV-free poinsettias. Traditionally, PnMV-free poinsettia plants were obtained by in vitro culture of apical meristems. However, it is a time-consuming method and the regenerated new PnMV-free poinsettia has sometimes lost the branching characteristics which is important for poinsettia. Therefore, we have developed Agrobacterium-mediated transformation approach for poinsettia. Using this method, we have produced transgenic poinsettia with improved resistance against poinsettia mosic virus (PMV). Molecular analyses have confirmed the stable integration of transgenes into the poinsettia genome. The mechanical inoculation experiments of PnMV and Elisa assays revealed the improved PnMV resistance among the transgenic lines. SiRNA analysis has revealed the gene silencing mediated resistance. This is the first report describing Agrobacterium-mediated transformation on poinsettia. The methodology developed could also facilitate the further improvement of this ornamental plant with aims to enhance its disease resistances, quality traits, desirable colour and ornamental values for meeting the markets demands.
Sammendrag
Fem nye mjøldoggtolerante sorter ble sammenlignet med målesorten "Rapides" i lyskultur med nedsenking og planting om høsten. Det ble ikke funnet forskjell i avling mellom sortene. Selv om det ble påvist forskjeller i agurkkvalitet, tidlighet og mjøldoggtoleranse, var ingen av sortene et klart bedre alternativ enn "Rapides".
Sammendrag
Agurkgrønnmosaikkvirus (Cucumber green mottle mosaic virus, CGMMV) er et svært smittsomt virus som hører til i Tobamovirus-slekten (samme slekten som tomatmosaikkvirus). CGMMV infiserer planter tilhørende gresskarfamilien (Cucurbitaceae). Hos oss er CGMMV bare å finne som skadegjører i agurk. CGMMV er påvist i mange land verden over - i andre land er det også påvist som skadegjører i vannmelon, melon og kalebass. Agurkgrønnmosaikkvirus er relativt vanlig forekommende i agurk i Europa, mens viruset har hatt en begrenset utbredelse i andre nordiske land de siste 25 årene med under 10 kjente tilfeller i hvert av landene i denne perioden. Etter at dette viruset ikke har vært funnet i Norge på over 20 år, har det nå dukket opp to tilfeller av dette viruset i Rogaland. Agurkgrønnmosaikkvirus er svært smittsomtl. Det er derfor er en utfordring å få til en god bekjempelse. Med godt kjennskap til symptomer, spredningsveier og mulige bekjempelsestiltak har vi imidlertid mulighet til å få til en vellykket kontroll av dette viruset.