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
Authors
Roshan M. Bajracharya Bishal K. Sitaula Subodh Sharma Alhaji S. JengAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Mehreteab TesfaiAbstract
No abstract has been registered
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