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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.

2024

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Abstract

Our investigation delves into the previously uncharted territory of cider composition from Norway. This study aimed to obtain an overview of the qualitative and quantitative compositions of general chemical parameters, polyphenols (individual and total expressed as gallic acids equivalents), selected esters, and selected C6-alcohols in ciders with the PDO label Cider from Hardanger. In total, 45 juice and cider samples from the fermentation process were collected from 10 cider producers in Hardanger in 2019, 2020, and 2021. Individual sugars, acids, ethanol, and 13 individual phenols were quantified using HPLC-UV/RI. Seven ethyl esters of fatty acids, four ethyl esters of branched fatty acids, ten acetate esters, two ethyl esters of hydroxycinnamic acids, and four C6-alcohols were quantified using HS-SPME-GC-MS. For samples of single cultivars (‘Aroma’, ‘Discovery’, ‘Gravenstein’, and ‘Summerred’), the sum of the measured individual polyphenols in the samples ranges, on average, from 79 to 289 mg L−1 (the lowest for ‘Summerred’ and highest for ‘Discovery’ and ‘Gravenstein’). Chlorogenic acid was the most abundant polyphenol in all samples. Ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl isobutyrate, ethyl 2-methylbutyrate, isoamyl acetate, and hexanol were present at concentrations above the odour threshold and contributed to the fruity flavour of the Cider from Hardanger.

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Norwegian apple ciders have recently gained attention at the levels of international competitiveness. Accordingly, a comparative study on the chemical composition of selected Norwegian and French apple ciders was conducted to gain knowledge on what ubiquitous chemical parameters make the Norwegian ciders different from ciders from well-established producing regions. A total of 43 ciders, 24 Norwegian and 19 French, in the category of acidic dominant ciders, were included in the study. Ethanol, individual sugars and organic acids, pH, total phenols, aroma compounds including esters, C6-alcohols, volatile phenols and terpenoids, were analysed. Norwegian ciders showed higher contents in ethanol, malic and citric acids, whereas total phenols, pH, glucose, and fructose were higher in French counterparts. Regarding the aromatic profile, no significant differences were observed for C6-alcohols. In contrast, differences were more expressed in the case of esters and volatile phenols. Norwegian ciders were characterised by higher average concentration for all the groups of esters, with the most important differences measured for higher alcohol acetates. Norwegian ciders also displayed higher contents of 4-vinylphenol and 4-vinylguaiacol while French ciders contained substantially higher levels of 4-ethylphenol and 4-ethylguaiacol. These results are in mutual correlation with the empirical observation reporting Norwegian apple ciders as more acidic, alcoholic and with lighter body but fruitier profile. Whereas French ciders are often perceived with more structure and animalistic profile.

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Abstract

In agricultural areas dominated by subsurface drainage, leaching of phosphorus (P) from soils is a concern for downstream water quality. Still, the role of chemical processes in subsoils and organic soils in influencing dissolved P leaching needs to be clarified for better predicting the P leaching. In ten mineral and organic soils, we examined a wide range of chemical characteristics including various P pools and sorption–desorption properties at different soil depths and related those characteristics to leaching of dissolved P at the drain depth in an indoor lysimeter experiment. Results showed significant correlations between different P pools (R2-adj = 0.61 to 0.98, p < 0.001) and between sorption capacity measurements (R2-adj = 0.60 to 0.95, p < 0.001). Some organic soils followed the same patterns in P sorption capacity and P lability as sandy soils but some did not, suggesting organic soils differ among themselves possibly due to differences in origin and/or management. Flow-weighted mean concentrations of dissolved reactive P and dissolved organic P depended on both the labile P pools (labile inorganic and organic P pools, respectively) in the topsoil and P sorption and desorption characteristics in the subsoils. Mass-weighted whole-profile degree of P saturation based on the ammonium lactate extraction method (DPS-AL) was an excellent indicator of flow-weighted mean concentration of total dissolved P (FWMC-TDP) (R2-adj = 0.93, p < 0.001). Two profiles, one with organic soils overlaying on sand and the other with sandy soils in all layers, had the greatest FWMC-TDP among all profiles (316 and 230 µg/L versus 33–84 µg/L) due to the same reason, i.e., large labile P pools in the topsoils, low P sorption capacity in the subsoils, and high whole-profile DPS-AL. All results point to the need to include subsoil characteristics for assessing the risks of dissolved P leaching from both mineral and organic soils. Also, the study suggests the need to investigate further the roles of the origin and management of organic matter and organic P in influencing P lability and dissolved organic P (DOP) leaching, as well as the bioavailability of DOP in recipient waters.

Abstract

The chilling requirements of ‘Junifer’, ‘Rovada’ and ‘Red Dutch’ red currants and ‘Mucurines’ and ‘Pax’ gooseberries were studied under controlled environment conditions. Field grown single-stem potted plants were chilled at 0°C from October 15 for 0 to 20 weeks and forced in a lighted greenhouse at 20°C and 18 h photoperiod for 60 days for recording of budbreak and flowering. None of the red currant plants were able to break without chilling, while the number of breaking buds increased linearly with more than four weeks of chilling, and fastest so in ‘Junifer’. ‘Red Dutch’ proved to have a particularly deep and stable dormancy. Comparable but markedly lower chilling requirements were found in the two gooseberry cultivars. While more than 20 weeks of chilling were required for full dormancy release in the red currant cultivars, 16 to 20 weeks were adequate for the ‘Mucurines’ and ‘Pax’ gooseberries, respectively. This compares with a chilling need of 14 weeks at 0°C previously found for most commercial black currant cultivars under the same conditions. The results also confirm that, as previously demonstrated for black currants, flower development requires more chilling than bud break itself also in red currants and gooseberries. This highlights the need for extended chilling of the plants before the plants are set to forcing in modern tunnel production. We also conclude that the red currant cultivar ‘Rovada’ with its large berry trusses seems particularly well suited for tunnel production.

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Root-knot nematodes (Meloidogyne spp.) are serious pests of most food crops, causing up to 100% yield loss. Nevertheless, commercial nematicides are costly and harmful to the environment. While the nematicidal potential of crustacean and synthetic chitin has been demonstrated globally, research on the potential of insect-derived chitin for nematode control has received limited attention. Here, seven chitin-fortified black soldier fly frass fertilizer extracts (chFE) were assessed for their suppressiveness of Meloidogyne incognita and impacts on spinach growth in comparison with a commercial nematicide using in vitro and in vivo bioassays. The performance of chFE and control treatments was assessed by determining their effects on nematode egg hatchability; infective juvenile (J2) mortality and paralysis; number of galls, egg masses, and J2s per plant; and spinach root and shoot biomass. In vitro results showed that chFE and commercial nematicide suppressed nematode egg hatchability by 42% and 52%, respectively, relative to the control (sterile distilled water). Up to 100% paralysis was achieved when M. incognita J2s were exposed to either chFE or commercial nematicide. Further, the J2 mortality achieved using chFE (95%) was comparable to the value achieved using commercial nematicide (96%); in all treatments, mortality increased with exposure time. Similarly, up to 85% suppression of gall development was achieved when spinach plants were grown in soil drenched with chFE; up to 79% reduction in egg mass formation and 68% suppression of J2 development in the root system were achieved using chFE. Also, chFE application significantly increased spinach root and shoot biomass by 54%–74% and 39%–58%, respectively, compared to commercial nematicide. Our findings demonstrate the nematicidal potential of chFE and its benefits on crop production. Thus, chFE could be considered as a promising multipurpose, regenerative, and cost-effective input for sustainable management of plant-parasitic nematodes and enhancement of crop yield.

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Future agricultural practices necessitate green alternatives to replace hazardous insecticides while distinguishing between pests and beneficial insects. Chitosan, as a biological macromolecule derived from chitin, is biodegradable and exhibits low toxicity to non-target organisms, making it a sustainable alternative to synthetic pesticides. This review identifies chitosan-derivatives for insecticidal activity and highlights its efficacy including genotoxicity, defense mechanism, and disruption of insect's exoskeleton at different concentrations against several insect pests. Similarly, synergistic effects of chitosan in combination with natural extracts, essential oils, and plant-derived compounds, enhances insecticidal action against various pests was evaluated. The chitosan-based insecticide formulations (CHIF) in the form of emulsions, microcapsules, and nanoparticles showed efficient insecticide action on the targeted pests with less environmental impact. The current challenges associated with the field-trial application were also recognized, by optimizing potent CHIF-formulation parameters, scaling-up process, and regulatory hurdles addressed alongside potential solutions. These findings will provide insight into achieving the EU mission of reducing chemical pesticides by 50 %.

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There is an increasing need for ecosystem-level distribution models (EDMs) and a better understanding of which factors affect their quality. We investigated how the performance and transferability of EDMs are influenced by 1) the choice of predictors and 2) model complexity. We modelled the distribution of 15 pre-classified ecosystem types in Norway using 252 predictors gridded to 100 × 100 m resolution. The ecosystem types are major types in the ‘Nature in Norway' system mainly defined by rule-based criteria such as whether soil or specific functional groups (e.g. trees) are present. The predictors were categorised into four groups, of which three represented proxies for natural, anthropogenic, or terrain processes (‘ecological predictors') and one represented spectral and structural characteristics of the surface observable from above (‘surface predictors'). Models were generated for five levels of model complexity. Model performance and transferability were evaluated with data collected independently of the training data. We found that 1) models trained with surface predictors only performed considerably better and were more transferable than models trained with ecological predictors, and 2) model performance increased with model complexity, levelling off from approximately 10 parameters and reaching a peak at approximately 20 parameters, while model transferability decreased with model complexity. Our findings suggest that surface predictors enhance EDM performance and transferability, most likely because they represent discernible surface characteristics of the ecosystem types. A poor match between the rule-based criteria that define the ecosystem types and the ecological predictors, which represent ecological processes, is a plausible explanation for why surface predictors better predict the distribution of ecosystem types. Our results indicate that, in most cases, the same models are not well suited for contrasting purposes, such as predicting where ecosystems are and explaining why they are there.

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Abstract

Fast regrowth from deep roots and rhizomes makes it difficult to mechanically control the perennials Cirsium arvense and Tussilago farfara respectively. It is, however, not clear whether new shoots originate mainly from fragments of roots/rhizomes in upper soil layers or from an intact system below depth of soil cultivation. Here we present results from three experiments with natural infestations of C. arvense, and two with both C. arvense and T. farfara. Plots of 1 m2 were excavated to different depths (13–25 cm), all below-ground plant parts in the topsoil were collected and thereafter fragments were either returned to or removed from the plots. Regrowth from disturbed plots with removed or returned fragments was compared. The origin of regrown shoots, that is, whether they originated from seeds, intact below-ground root/rhizome systems or returned fragments, was examined. More C. arvense shoots originated from the intact root system (48%–84%) than from root fragments (16%–52%). The final aboveground biomass was not affected by removal of the top-soil fragments. For T. farfara, a small proportion (3%) of new shoots originated from the intact rhizome system, and the rest from fragments. We conclude that the intact root system of C. arvense contributes at least as much as root fragments to regrowth after soil cultivation, which might imply that time of treatment and depth of cultivation are crucial for the effect of mechanical control. For T. farfara, the results suggest that tillage equipment with high capacity to fragment the rhizome system will contribute to efficient control.

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Climate change causes far-reaching disruption in nature, where tolerance thresholds already have been exceeded for some plants and animals. In the short term, deer may respond to climate through individual physiological and behavioral responses. Over time, individual responses can aggregate to the population level and ultimately lead to evolutionary adaptations. We systematically reviewed the literature (published 2000–2022) to summarize the effect of temperature, rainfall, snow, combined measures (e.g., the North Atlantic Oscillation), and extreme events, on deer species inhabiting boreal and temperate forests in terms of their physiology, spatial use, and population dynamics. We targeted deer species that inhabit relevant biomes in North America, Europe, and Asia: moose, roe deer, wapiti, red deer, sika deer, fallow deer, white-tailed deer, mule deer, caribou, and reindeer. Our review (218 papers) shows that many deer populations will likely benefit in part from warmer winters, but hotter and drier summers may exceed their physiological tolerances. We found support for deer expressing both morphological, physiological, and behavioral plasticity in response to climate variability. For example, some deer species can limit the effects of harsh weather conditions by modifying habitat use and daily activity patterns, while the physiological responses of female deer can lead to long-lasting effects on population dynamics. We identified 20 patterns, among which some illustrate antagonistic pathways, suggesting that detrimental effects will cancel out some of the benefits of climate change. Our findings highlight the influence of local variables (e.g., population density and predation) on how deer will respond to climatic conditions. We identified several knowledge gaps, such as studies regarding the potential impact on these animals of extreme weather events, snow type, and wetter autumns. The patterns we have identified in this literature review should help managers understand how populations of deer may be affected by regionally projected futures regarding temperature, rainfall, and snow.