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.
2019
Forfattere
Kamilla Skaalsveen Julie Ingram Lucy ClarkeSammendrag
This review provides a comprehensive evaluation of no-till (NT) based on recent studies (post-2000) in NW Europe and evaluates the separate effect of the NT and other associated practices (e.g. cover crops, crop residue and crop rotations) individually and collectively on the water purification and retention functions of the soil. It also assesses the applicability of NT compared to conventional tillage (CT) systems with reference to a number of soil physical characteristics and processes known to have an important influence on water purification and retention functions. The literature search was carried out by a systematic approach where NT practices were assessed against soil structure, erosion, nutrient leaching/loss, water retention, infiltration and hydraulic conductivity (combinations of criteria = 40). Articles were selected based on their relevance in relation to the topic and location within NW Europe (n = 174). Results show that NT has large potential as an erosion mitigation measure in NW Europe with significant reductions of soil losses from agricultural fields, providing potential beneficial effects regarding inputs of sediment and particulate phosphorous (P) to water bodies. However, NT increased losses of dissolved reactive phosphorus (DRP) and had little effect on nitrogen (N) leaching, limiting the overall positive effects on water purification. Soil structural properties were often found to be poorer under NT than CT soils, resulting in decreased water infiltration rates and lower hydraulic conductivity. This was an effect of increased topsoil compaction, reduced porosity and high bulk density under NT, caused by the absence of topsoil inversion that breaks up compacted topsoil pans and enhances porosity under CT. However, several studies showed that soil structure under NT could be improved considerably by introducing cover crops, but root and canopy characteristics of the cover crop are crucial to the achieve the desired effect (e.g. thick rooted cover crops beneficial to soil structural remediation can cause negative effects in soils sensitive to erosion) and should be considered carefully before implementation. The contribution of NT practices to achieve Water Framework Directive (WFD) objectives in NW Europe is still uncertain, in particular in regards to water retention and flood mitigation, and more research is required on the total upscaled effects of NT practices on catchment or farm scale.
Sammendrag
The use of blankets in horses is widespread in Northern Europe. However, horses are very adaptable to low temperatures and the practice is questioned because blankets may hamper heat dissipation at high temperatures and also disturb free movement. The aim of the current study was to gain information about horses’ own preferences for wearing or not wearing a blanket under different weather conditions during the seasons. 10 horses usually wearing blankets and 13 horses usually not wearing blankets were kept outside in their paddock for 2 h during different weather conditions. Then, these horses were tested for their preference for wearing blankets (see Mejdell et al., 2016). When only considering air temperature and not the impact of other weather factors, the horses preferred to have the blanket on in 80% and 90% of the test at t < -10 °C in horses usually wearing and not wearing blankets, respectively. As air temperature increased, the preference for keeping the blanket on decreased and at air temperatures > 20 °C, the horses preferred to remove the blanket in all the tests. According to the statistical model, the probability for choosing to have a blanket on increased with increasing wind speed, and also precipitation increased the probability for choosing to have a blanket on. Sunshine however, reduced the probability for choosing to wear a blanket.
Forfattere
Magne SætersdalSammendrag
Det er ikke registrert sammendrag
Forfattere
O. Janne Kjønaas Ivika Ostonen Lars Vesterdal Raija Laiho Tuula Larmola Edda S. Oddsdóttir Zane Libiete Iveta Varnagirytė-KabašinskienėSammendrag
Det er ikke registrert sammendrag
Sammendrag
We distinguish five Xanthomendoza species in Norway, viz., X. borealis, X. fallax, X. fulva, X. oregana, and X. ulophyllodes, based on morphology and molecular evidence. This paper gives an updated taxonomy of the Norwegian species of Xanthomendoza, and addresses previous misconceptions. Xanthomendoza ulophyllodes is reported as occurring in Norway. The species was previously misunderstood in Norway and removed from the Nordic checklist. We show that the nuclear internal transcribed spacer (nrITS) is a useful barcode marker for the treated species. We provide a key and short descriptions of the species, with notes on specific issues, ecology, geographic distribution, illustrations, maps, and a DNA reference library (DNA barcoding).
Sammendrag
In this paper, we present a novel method for obstacle avoidance designed for a nonholonomic mobile robot. The method relies on light detection and ranging (LiDAR) readings, which are mapped into a polar coordinate system. Obstacles are taken into consideration when they are within a predefined radius from the robot. A central part of the approach is a new Heading Weight Function (HWF), in which the beams within the aperture angle of the LiDAR are virtually weighted in order to generate the best trajectory candidate for the robot. The HWF is designed to find a solution also in the case of a local-minima situation. The function is coupled with the robot’s controller in order to provide both linear and angular velocities. We tested the method both by simulations in a digital environment with a range of different static obstacles, and in a real, experimental environment including static and dynamic obstacles. The results showed that when utilizing the novel HWF, the robot was able to navigate safely toward the target while avoiding all obstacles included in the tests. Our findings thus show that it is possible for a robot to navigate safely in a populated environment using this method, and that sufficient efficiency in navigation may be obtained without basing the method on a global planner. This is particularly promising for navigation challenges occurring in unknown environments where models of the world cannot be obtained.
Forfattere
O. Janne Kjønaas Teresa Gómez de la Bárcena Ryan Bright Mette Hanssen Gro Hylen Håvard Kauserud Tonje Økland Mundra Sunil Jørn-Frode Nordbakken Carlo AallSammendrag
Det er ikke registrert sammendrag
Forfattere
Trygve S. AamlidSammendrag
Det er ikke registrert sammendrag
Forfattere
Rebecka Ringman Greeley Beck Annica PilgårdSammendrag
The effect of wood modification on wood-water interactions in modified wood is poorly understood, even though water is a critical factor in fungal wood degradation. A previous review suggested that decay resistance in modified wood is caused by a reduced wood moisture content (MC) that inhibits the diffusion of oxidative fungal metabolites. It has been reported that a MC below 23%–25% will protect wood from decay, which correlates with the weight percent gain (WPG) level seen to inhibit decay in modified wood for several different kinds of wood modifications. In this review, the focus is on the role of water in brown rot decay of chemically and thermally modified wood. The study synthesizes recent advances in the inhibition of decay and the effects of wood modification on the MC and moisture relationships in modified wood. We discuss three potential mechanisms for diffusion inhibition in modified wood: (i) nanopore blocking; (ii) capillary condensation in nanopores; and (iii) plasticization of hemicelluloses. The nanopore blocking theory works well with cell wall bulking and crosslinking modifications, but it seems less applicable to thermal modification, which may increase nanoporosity. Preventing the formation of capillary water in nanopores also explains cell wall bulking modification well. However, the possibility of increased nanoporosity in thermally modified wood and increased wood-water surface tension for 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU) modification complicate the interpretation of this theory for these modifications. Inhibition of hemicellulose plasticization fits well with diffusion prevention in acetylated, DMDHEU and thermally modified wood, but plasticity in furfurylated wood may be increased. We also point out that the different mechanisms are not mutually exclusive, and it may be the case that they all play some role to varying degrees for each modification. Furthermore, we highlight recent work which shows that brown rot fungi will eventually degrade modified wood materials, even at high treatment levels. The herein reviewed literature suggests that the modification itself may initially be degraded, followed by an increase in wood cell wall MC to a level where chemical transport is possible.
Forfattere
Stephanie EisnerSammendrag
Det er ikke registrert sammendrag