Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2007
Abstract
No abstract has been registered
Authors
Peder GjerdrumAbstract
Predicting the yield and quality of sawn timber continues to be a challenging task, influenced by several stochastic processes: Log dimension and shape under bark varies, accuracy of sawing is not perfect, etc. This work presents an annotated model based on an approach successfully applied in the industry through a couple of decades. A number of important timber yield predictors are identified, and the following models give unbiased yield estimates. Being in need of adjustment before transferring to new locations, the approach might be considered a powerful tool to analyse and improve the operation, rather than a complete model in itself. Nevertheless, the notional, purely geometric, models might be superior for analysing unfamiliar sawing patterns, even if they tend to overestimate the yield. Thus, the two methods should preferably be used in combination, rather than one replacing the other. Finally, the everyday use of such models is illustrated and a procedure for associating sawn timber with suitable logs is outlined.
Authors
Trond Henriksen Audun Korsæth Tor Arvid Breland Bo Stenberg Lars Stoumann Jensen Sander Bruun Jon Gudmundsson Fridrik Palmason Anders Pedersen Tapio SaloAbstract
Mechanistic, multi-compartment decomposition models require that carbon (C) and nitrogen (N) in plant material be distributed among pools of different degradability. For this purpose, measured concentrations of C and N in fractions obtained through stepwise chemical digestion (SCD) and values predicted from near-infrared (NIR) spectra or total plant N concentration were compared. Seventysix cash, forage, green manure and cover crop plant materials representing a wide range in biological origin and chemical quality were incubated in a sandy soil at 15 degrees C and -10 kPa water potential for 217 d. A mechanistic decomposition model was calibrated with data from soil without plant material and initialised by data on amounts of C and N in fractions obtained from SCD directly or C and N in SCD fractions as predicted from NIR spectroscopy or plant N concentration. All model parameters describing C and N flows from plant material were kept at default values as defined in previous, independent works with the same model. When results from SCD were used directly to initialise the decomposition model, C and N mineralisation dynamics were predicted well (r(2) = 0.76 and 0.70 for C mineralisation rates and accumulation of inorganic N, respectively). When a NIR calibration was used to predict the SCD data, this resulted in nearly equally good model performance (r(2) = 0.76 and 0.69 for C and N mineralisation, respectively). This was also the case when SCD data were predicted from plant material N concentration (r(2) = 0.76 and 0.69 for C and N). We conclude that the combined use of a mechanistic decomposition model and quality data from SCD is a highly adequate basis for an a priori description of the mineralisation of both C and N from common agricultural plant materials, and that both NIR spectroscopy and measurement of total N concentration offer good and cost-effective alternatives if they are calibrated with SCD data. (C) 2007 Elsevier Ltd. All rights reserved.
Abstract
To study physiological and biochemical effects of demethylation inhibitor (DMI) fungicides on non-target insects, larvae of the cabbage moth, Mamestra brassicae L., were exposed orally to propiconazole, (R,S)-1-[2-(2,4-diclophenyl)-4-propyl-1,3-dioolan-2-ylmetyl]-1H-1,2,4-triazole (100, 200 and 600 mg L−1) and fenpropimorph, (±)-cis-4-[3-(4-tert-butylphenyl)-2-methylpropyl] 2,6-dimethylmorpholinc (10, 100, 200 and 600 mg L−1) in a semi-synthetic diet. Ten mg L−1 of fenpropimorph reduced larval weight and induced in vitro glutathione S-transferase activity. Reduced larval and pupal growth rate, reduced survival, prolonged developmental time, and altered patterns of larval survival and adult emergence were found for one or both fungicides in at least one of the concentrations tested. The results suggest, that although the use of agricultural fungicides is generally regarded as of minor ecotoxicological consequence for insects, feeding on DMI-treated crops may influence insect fitness, and may also leave them susceptible to pesticide treatments or to residues of pesticides and other pollutants in their food. Standard methods to detect such effects should be developed for use in the environmental risk assessment of these products.
Abstract
No abstract has been registered
Academic – Stochastic utility-efficient programming of organic dairy farms
Ola Flaten, Gudbrand Lien
Abstract
No abstract has been registered
Authors
Arnstein Staverløkk May SæthreAbstract
Dispersal of alien species, plant pests and other organisms through trade with living plants and plant parts increases with globalisation. Every year a significant amount of horticultural plants for use in urban landscapes and private gardens are imported to Norway from several other European countries. The last decade the amount of such import to Norway has doubled, while the resources allocated for phytosanitary control of this goods on arrival has not had a similar development. Trees and bushes for outdoor use pose a special risk for carrying unwanted stowaways since they are mostly produced outdoors in the export country and are in addition frequently exported with a lump of soil from the production site. After arrival in Norway the plants are dispersed quickly to all parts of the country where they are sold to private and official buyers. The quick handling of this material makes it easy for an organism to stay alive and have the opportunity to establish in the new environment. A study was carried out in 2006 to aiming to find out more about this trade, particularly emphasizing on identifying species of insects and arachnids that were suspected to pass through the national control system. Mattilsynet, the Norwegian Food Safety Authority, is the National Plant Protection Organization of Norway, and perform random sampling of imported plant commodities of this type. Unfortunately, there is practically no surveillance on the introduction of species that are not on the quarantine pest list, and the standard control routines fail in detecting and rejecting plant commodities that contain non-quarantine species. In this study it was mainly searched for insects and arachnids, but snails and slugs, millipedes and other organisms were also found. The plant species sampled were mostly conifers, of which Thuja sp. and Taxus sp. were the majority. Conifers turned out to be excellent in providing shelter and hiding places for small organisms. Three sampling methods were used: 1. Shaking method, 2. Visual observation and 3. Sampling of the compost fallen off the consignments during the transport. The last method added most species to the list. In only six samples of compost investigated as much as 93 different species were identified. During a short period of sampling 1193 individuals were collected travelling as stowaways mainly from Germany, Denmark and the Netherlands. 156 species were identified and additional 26 organisms were identified to the genus level.
Authors
Lars T. HavstadAbstract
Different methods of straw residue management were evaluated in field trials with seed crops of timothy (Phleum pratense L.) and meadow fescue (Festuca pratensis Huds.) in SE Norway during 2000-2005. Compared to straw removal, which up to now has been the most common straw management practice in seed production of the two species, straw chopping and spreading at the back of the combiner during seed harvest did not reduce seed yield in the following year when stubble height was kept at a low level (preferably less than 10 cm). However, in order for newly developed tillers to rapidly penetrate the straw layer in autumn, the chopped straw had to be spread uniformly in the field. The experiments did not provide any support for an extra input of nitrogen in autumn, either in timothy or meadow fescue, when the straw was chopped rather than removed. In both species, also burning of straw and stubble soon after seed harvest was an efficient and fast clean-up method in the field after harvest. However, due to problems with smoke emission, especially near traffic roads and populated areas, field burning is not recommended as a preferable straw management method.
Authors
Arne Fjellberg Per Holm Nygaard Odd Egil StabbetorpAbstract
No abstract has been registered
Abstract
Empirical evidence that the N dissipation from dairy production depends tightly on the segregation of animals from plant production is provided