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.
2017
Authors
Olalla Díaz-Yáñez Blas Mola-Yudego José Ramón González-Olabarria Timo PukkalaAbstract
The risk of snow and wind damage should be considered when deciding forest management actions, as it can greatly change forest development and its accompanying services. In this study, we develop models that predict snow and wind damage using management related variables as predictors. The plot level models are based on the extensive data available for Norwegian forests from four consecutive measurements of the national forest inventory along the period 1995–2014. The snow and wind risk is assessed in pure stands (pine, spruce and birch) as well as for mixed stands. Separate models are constructed for predicting the probability of a tree to be damaged, broken or uprooted. The models’ descriptors include: mean diameter, mean tree slenderness, mean height, basal area and a portfolio of variables related to stand structure and composition. The models are based on generalized linear models assuming binomial or quasi-binomial distributions resulting in nine models. Mixed stands are the stands most commonly affected by snow and wind damage followed by spruce dominated stands. Spruce stands with more heterogeneous structures are less prone to suffer breakage of trees, and increasing stand height have a big impact on the risk of tree breakage. The models presented in this study can be used to create management prescriptions considering the risk of snow and wind damage. These models also help to better understand which variables make a forest more vulnerable to snow and wind damage.
Authors
Hans Thodsen Csilla Farkas Jaroslaw Chormanski Dennis Trolle Gitte Blicher-Mathiesen Ruth Grant Alexander Melvold Engebretsen Ignacy Kardel Hans Estrup AndersenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Eldrid Lein MoltebergAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Nina Johansen Belachew Asalf Tadesse Aruppillai Suthaparan Arne Stensvand Pål Johan From David Gadoury Lars Grimstad Carl Emil ØyriAbstract
No abstract has been registered
Abstract
Matching high performing varieties of legumes with effective symbiotic N-fixing bacteria can potentially enhance production volumes and economic returns when cultivating grain legumes. We investigated whether field inoculation with local or introduced Rhizobia to six different varieties of faba bean improved growth, nitrogen (N) fixation and protein content in a field experiment in Southern Norway. In 2016, a full factorial experiment featuring three inoculation treatments (a mixture of four morphotypes of Rhizobia isolated from locally grown faba bean, a mix of two efficient and well documented Rhizobium strains from Latvia, and a non-inoculated control treatment) and six faba bean (Vicia faba) genotypes (Agua Dulce, Bauska, Jõgeva, Gloria, Julia, Lielplatones) was set up in an experimental field with sandy loam soil with no recent legume culture history (>10 years). At late flowering/early pod formation stage we quantified N fixation of the crop using the N-15 natural abundance method, using weeds from the same plots as reference plants. We also assessed morphological and phenological characters, seed yields and protein levels at plant maturity. Clear differences were observed, and detailed results from this study will be presented at the conference (analyses are still pending). This research is a part of the EU FP7 project Eurolegume.
Abstract
Nighttime ultraviolet (UV) radiation, if applied properly, has a significant potential for management of powdery mildews in many crop species. In this study, the role of growth light duration, irradiance, a combination of both (daily light integral) and light spectral quality (blue or red) on the efficacy of UV treatments against powdery mildew caused by Podosphaera xanthii and the growth performance of cucumber plants was studied in growth chambers. Increasing daily light integral provided by high-pressure sodium lamps (HPS) decreased efficacy of nighttime UV treatments against P. xanthii, but it increased plant growth. Furthermore, the efficacy of nighttime UV decreased when day length was increased from 16 to 20 h at a constant daily light integral. The efficacy of nighttime UV increased if red light was applied after UV treatment, showing the possibility of day length extension without reducing the effect of UV. Increasing the dose of blue light during daytime reduced the efficacy of nighttime UV in controlling the disease, whereas blue deficient growth light (< 6% of blue) caused UV mediated curling of young leaves. Furthermore, application of blue light after nighttime UV reduced its disease control efficacy. This showed the importance of maintaining a minimum of blue light in the growth light before nighttime UV treatment. Findings from this study showed that optimization of nighttime UV for management of powdery mildew is dependent on the spectral composition of the photosynthetically active radiation.
Abstract
No abstract has been registered
Abstract
Plants of six strawberry cultivars were raised under controlled conditions and tested for flowering and yield potential. Short days (SD) at intermediate temperatures for 4 weeks in August induced profuse flowering in subsequent long days (LD) in all cultivars except the late-flowering ‘Malwina’. LD conditions induced flowering only in ‘Nobel’, which has an everbearing parent. ‘Nobel’ and ‘Saga’ exhibited broad temperature adaptation for SD floral induction, which was generally reduced or suppressed at 9 and 27°C. After autumn planting, all cultivars flowered most abundantly in plants raised in SD and intermediate temperatures. Flowering was earliest in ‘Nobel’ and ‘Rumba’. Plants that did not reach floral commitment after 4 weeks in SD continued and completed induction under subsequent natural SD conditions after planting in the field, demonstrating the capability of fractional induction. Berry yield varied in parallel with flowering in the field and was always higher in plants raised under SD conditions. The traditional cultivars ‘Florence’ and ‘Sonata’ out-yielded the more recent cultivars. Some cultivars lost more than two thirds of their initiated flowers during the winter with obvious consequences for their yields. With proper raising management, acceptable yields were obtained after autumn planting even in a cool Nordic climate.