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
Sammendrag
High tunnels offer an intensive and protective production system for many fruit crops. In May 2014, two tractor-accessible Haygrove® multibay tunnel systems were installed on a 10% slope at the experimental farm at Nibio Ullensvang, western Norway (60°19’8.03”N, 6°39’14.31”E). Feathered 1-year old European plum cultivar ‘Opal’ on rootstock ‘St. Julien A’ were planted with two rows per bay at a spacing of 1.5×4 m during 2012. Trees were trained to a central leader as free spindles. In 2016, one tunnel was covered (150 μm clear classic polyethylene film) from before blooming until harvest and one tunnel only covered from mid-July till harvest. Different crop loads levels were established by blossom thinning (each flower 5, 10, and 15 cm apart), and fruitlet thinning (each fruitlet 5, 10, and 15 cm apart) at 10-12 mm fruitlet diameter at the end of June. Treatments were applied on single whole trees in a randomized complete block design with five replications. Climatic parameters were monitored inside and outside the tunnels from mid-June to mid-September. Fruit set, yield data, and fruit quality parameters for each treatment were recorded. Increased thinning distances reduced the fruit set and was highest when thinned at fruitlets. Thinning to 5 cm apart and covered the whole season and 10 cm apart covered one month gave the highest fruit sets of 17.9 and 14.3%, respectively. The yield was positively correlated with the fruit set response, 11.7 kg tree-1 (20 t ha-1) – 5 cm between fruitlets and short-covering versus 3.4 kg – 15 cm distance between flowers and long covering. Both blossom and fruitlet thinned trees when covered got a significant yield reduction compared to covered one month. Thinning at the fruitlet stage resulted in smaller fruits at the same crop level (41.3 g on average) compared to flower thinning for both covering periods (47.2 g). Qualitative traits of ’Opal’ plums (bright yellow ground colour, red over colour, and soluble solid contents) were weakly correlated with the fruit set and was high (16.7% average soluble solids content). The coverage from bloom to harvest time promoted maturity of the plums. From the preliminary results, it can be concluded that fruitlets thinning from uncovered trees and one month covering before harvesting gave the largest crop of premium fruits.
Sammendrag
A novel method for age-independent site index estimation is demonstrated using repeated single-tree airborne laser scanning (ALS) data. A spruce-dominated study area of 114 km2 in southern Norway was covered by single-tree ALS twice, i.e. in 2008 and 2014. We identified top height trees wall-to-wall, and for each of them we derived based on the two heights and the 6-year period length. We reconstructed past, annual height growth in a field campaign on 31 sample trees, and this showed good correspondence with ALS based heights. We found a considerable increase in site index, i.e. about 5 m in the H40 system, from the old site index values. This increase corresponded to a productivity increase of 62%. This increase appeared to mainly represent a real temporal trend caused by changing growing conditions. In addition, the increase could partly result from underestimation in old site index values. The method has the advantages of not requiring tree-age data, of representing current growing conditions, and as well that it is a cost-effective method with wall-towall coverage. In slow-growing forests and short time periods, the method is least reliable due to possible systematic differences in canopy penetration between repeated ALS scans.
Forfattere
Bjørn ØklandSammendrag
The populations sizes of Ips typographus in Norway have been monitored since the last big outbreak period in the 1970s. By now the monitoring programme includes about 500 pheromone-baited trap records for each of the last 40 years. Normally, Ips typographus has been the only species of major concern in northern bark beetle outbreaks, and trapping records have served as a warning when the over-wintering population sizes are large. In contrast to Central Europe, the regional trend in northwest is that rainy weather tend to slow down the bark beetle populations in many years, whereas stormfelling episodes of spruces, snowbreaks and warm and dry seasons in certain years favour Ips typographus and other bark beetle species. Recent observations indicate that other less aggressive bark beetle species may play a more important role during severe drought periods that follow rainful seasons with low production of Ips typographus. It is likely that an increased frequency of extreme weather events may have unexpected effects on what bark beetles become abundant during the course of the outbreaks. Furthermore, the warm years seem to be especially favourable for the Ips typographus at the northernmost latitudes. In addition, a new bark beetle species for Scandinavia, Ips amitinus, is expanding its range and may become a participant in future bark beetle outbreaks in this region.
Sammendrag
Mediterranean climate areas are home to highly relevant and distinctive agro-ecosystems, where sustainability is threatened by water scarcity and continuous loss of soil organic carbon. In these systems, recycling strategies to close the loop between crop production (and agrorelated industries) and soil conservation are of special interest in the current context of climate change mitigation. Pyrolysis represents a recycling option for the production of energy and biochar, a carbonaceous product with a wide range of environmental and agronomic applications. Considering that biochar functionality depends on both the original biomass and the pyrolysis conditions, we produced and characterized 22 biochars in order to evaluate their potential to sequester C and modify soil physicochemical properties. The pore size distribution was a function of the original biomass and did not change with the temperature of pyrolysis. The highest number of pores within the size 0.2−30 μm, relevant for plant available water retention, was reached at 600 °C. However, ideal pyrolysis conditions to optimize C stability and hydrologic properties was reached at 400 °C in woody derived biochars, as higher temperatures lead to a nontransient hydrophobicity. This study highlights relevant physicochemical properties of locally derived biochars that can be used to tackle specific challenges in Mediterranean agroecosystems.
Sammendrag
In many areas where spring is wet, fungicides are applied in relation to rain events that trigger ejection of ascospores of Venturia inaequalis, which cause primary infections of apple scab. Past studies established the rate of ejection during rain in relation to light and temperature, and determined the wetting time required for infection. Simulation software uses this information to calculate risk and help time sprays accordingly. However, the distribution of the infection time required by a population of spores landed on leaves was never studied, and assumptions were used. To estimate this, we inoculated ascospores of V. inaequalis on potted trees at different temperatures for specific wetting times. Lesions were enumerated after incubation. Lesions increased with wetness time and leveled off once the slowest spores infected the host, closely matching the monomolecular model. Wetness hours were best adjusted for temperature using the Yin equation. The minimum infection time on the youngest leaves was about 5 h, matching results from previous studies, whereas half the lesions appeared after 7 h of infection. Infection times for leaves with ontogenic resistance were longer. Our results improve current software estimates and may improve spraying decisions.
Sammendrag
This article describes the first implementation of green treatment technology for wastewater from agritourism facilities in Romania. The general concept was based on the principles of a nature-based treatment system (NBTS) developed, tested and successfully operated in cold climate in Norway. Two NBTSs, each constituting a three-element system equipped with a septic tank, a pre-treatment section and a filter/wetland bed, were constructed and set in full operation in Mara and Vadu Izei villages (Maramures County, Northern Romania, Carpathian Mountains). Both systems revealed sufficient adaptation to wastewater treatment during the first year of operation. The highest removal rates of BOD5, CODCr, Ntot and Ptot reached 93–97%, 94–98%, 97–98% and 98–99%, respectively. In addition, these parameters did not exceed their permitted values in effluents discharged to water bodies. Both systems demonstrate integrated measures of ecological engineering implemented as “treatment gardens” perfectly suited to the tourist facilities, rural surroundings and cultural landscape of the region.
Sammendrag
Norway has a political goal to minimize the loss of cultural heritage due to removal, destruction or decay. On behalf of the national Directorate for Cultural Heritage, we have developed methods to monitor Cultural Heritage Environments. The complementary set of methods includes (1) landscape mapping through interpretation of aerial photographs, including field control of the map data, (2) qualitative and quantitative initial and repeat landscape photography, (3) field recording of cultural heritage objects including preparatory analysis of public statistical data, and (4) recording of stakeholder attitudes, perceptions and opinions. We applied these methods for the first time to the historical clustered farm settlement of Havrå in Hordaland County, West Norway. The methods are documented in a handbook and can be applied as a toolbox, where different monitoring methods or frequency of repeat recording may be selected, dependent on local situations, e.g., on the landscape character of the area in focus.
Forfattere
Eric Post Eva Beyen Pernille Sporon Bøving R. Conor Higgins Christian John Jeff Kerby Christian Pedersen David A. WattsSammendrag
We report an observation of a flightless fledgling Lapland longspur (Calcarius lapponicus (Linnaeus, 1758)) at a long-term study site near Kangerlussuaq, Greenland, in late July 2018. Based on our observations of longspur nests at the site dating back to 1993, we estimate that the fledgling observed in 2018 may have originated from a nest initiated 12–37 d later than nesting in previous years. Onset of spring in 2018 was late, but comparable with other years in which longspur nests were observed a full calendar month earlier than in 2018. An analysis including multiple candidate predictor variables revealed a strong negative association between estimated longspur nest initiation dates and mean May temperature, as well as a weaker association with the length of the annual period of vegetation green up at the site. Given the limitations of our data, however, we are unable to assign causality to the 2018 observation, and cannot rule out other possibilities, such as that it may have resulted from a second clutch.
Sammendrag
Det ble sommeren 2017 og 2018 gjennomført et artleggingsprogram for å undersøke om plantemateriale av jordbær som var nylig importert, kunne være infisert av virus. Det ble tatt ut stikkprøver i jordbærfeltene hos utvalgte bærprodusenter som hadde baser sin produksjon på importerte planter, i 2017 til sammen 150 prøver fra 20 bruk i fylkene Hedmark, Oppland, Vestfold, Buskerud, Agder, Rogaland og Sogn og Fjordane. I 2018 ble det tatt ut 156 prøver fra 14 bruk i fylkene Østfold, Akershus, Møre og Romsdal og Trøndelag. Disse prøvene ble testet for fire bladlusoverførte virus som er relativt vanlige i Europa, men ikke i Norden: jordbær-nervebåndvirus (strawberry vein banding virus, SVBV), jordbær-mildmosaikkvirus (strawberry mottle virus, SMoV), jordbær-bladgulningvirus (strawberry mild yellow edge virus, SMYEV) og jordbær-bladkrøllevirus (strawberry crinkle virus, SCV). Det ble i 2017 påvist virus i prøver fra tre lokaliteter: SCV ble funnet på tre steder, mens SMYEV ble funnet på ett sted i en prøve som hadde dobbeltinfeksjon med SMYEV og SCV. Prøvene hadde ikke synlige symptomer. I 2018 ble det blant 156 prøver påvist virus i én prøve – det var SVBV i en prøve av ‘Sonata’ i Akershus. Denne prøven hadde heller ikke synlige symptomer.
Forfattere
Ljiljana Keca M. Marceta Gregor Bozic Sanja Peric Ivaylo Tsvetkov Kjell Andreassen A. Stijovic D. Mandzukovski Brane Zlokapa Valeriu Norocel NicolescuSammendrag
The prospects and challenges for non-native tree species (NNTS) in Southeast Europe (SEE) were analyzed using a combination of SWOT Analysis and the Analytic Hierarchy Process (AHP). Preference data from three groups of opinion leaders with extensive knowledge of the silviculture, ecology and impact of climate change on NNTS in SEE (researchers, practitioners and decision-makers) were used. Results revealed that strengths and opportunities for all three analyzed elements outweigh their weaknesses and threats. In the review of silviculture, key strengths and opportunities were identified as high p roductivity, adaptation to afforestation of degraded lands, gap filling in forest ecosystems after the loss of native tree species, and higher volume growth of NNTS compared to native tree species. Strength-Opportunity (SO) elements related to climate change were found to be adaptive management responsiveness to climate change and increased length of growing period, possibility of better-adapted mixtures with NNTS under climate change, and replacement of tree species that are sensitive to pests and outbreaks resulting from climate change. These results provide important insights into different segments of strategy approach of sustainable management of NNTS in relation to management, silviculture and climate change practices in SEE.