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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.

2017

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Swede is known as a healthy vegetable with a high content of vitamin C. However, very few studies have worked with the aim to evaluate how varieties, soil type and fertilizer interact and affect quality in swede. In the present study two varieties of swedes (‘Vige’ and ‘Vigod’) were grown on peat, loam and sand, with three levels of K (0, 120, 240 kg ha-1) and N fertilizer (0, 80, 160 kg ha-1). Low to moderate levels of N gave highest saleable yield, highest content of vitamin C and lowest content of nitrate. Peat soil gave highest saleable yield, lowest soluble solids and vitamin C and highest nitrate content. Soluble solids and vitamin C were negatively correlated with total root yield. Sandy soil gave lowest saleable yield, sweetest taste and lowest nitrate content. Contents of total, aliphatic, indole and individual glucosinolates, on dry matter basis, were highest on peat. N fertilization increased the content of most glucosinolates, whereas K affected glucobrassicin at the highest N level. Progoitrin was lowest in roots grown on sand, and was affected by N level and variety on sand and loam soils. Consumers preferred ‘Vigod’, which had the highest intensity of sweetness, although ‘Vige’ had more vitamin C and less nitrate.

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Plums contain high levels of hydroxycinnamates (neo-chlorogenic acid, Neo-CGA), anthocyanins (ATH) and ascorbic acid. The drying process influences their phytochemical content and plum cultivars are known to have different phytochemical retention after drying, but little data exists regarding to possible differences between conventional (CONV) and organic (ORG) plums. The aim of this study was to evaluate the phytochemical content in three different CONV and ORG plum cultivars (Jubileum, Reeves and Victoria) after freeze drying (FD), conventional oven drying (OD) and solar drying (SD). The three cultivars responded differently to the methods of drying. Notably, Jubileum decreased its ATH mostly when subjected to OD while its Neo-CGA content was mostly reduced after SD. Additionally, ORG Victoria and Reeves stood out for the low decrease of Neo-CGA after drying compared to the same cultivars cultivated with conventional system. The Folin-Ciocalteu index, which was significantly different in OD (6942 mg GAE/kg dw) and SD (5420 mg GAE/kg dw) samples, was positively related with both Neo-CGA and hydroxymethylfurfural. The present findings suggest that for some cultivars, the organic system influences the nutraceutical quality of dried product, thus representing an important factor that regulates the phytochemical content of dried plums.

Sammendrag

Changes in forest management have been suggested as a government policy to mitigate climate change in Norway. Tree species change is one of the major strategies considered, with the aim to increase the annual uptake of CO2 as well as the long-term storage of carbon (C) in forests. The strategy includes replacing native, deciduous species with fast-growing species, mainly Norway spruce. Forests in western Norway host some of the largest soil C pools in Scandinavia, and may potentially function as a long-term C reservoir as well as a large source of atmospheric CO2 through decomposition. The project BalanC was initiated in 2016 in order to estimate the C storage potential related to tree species in a total of 15 parallel plots of birch and planted Norway spruce at 5 locations in western Norway. In addition to estimates of C stocks in biomass and soils, we investigate soil C processes, soil fungal and earthworm diversity, albedo, and wood product life-cycles. The current presentation focuses on C stocks in soils relative to trees, soil respiration, and soil climate data. Preliminary results indicate that the soil respiration in spruce was 85 % of the respiration in birch, with a span ranging from 55-151%. The preliminary soil temperature and soil moisture data of the spruce stands were 97 and 73%, respectively, of the birch stands, indicating cooler and drier conditions under spruce which may affect decomposition and C accumulation rates. We expect C allocation in the soil to be affected by tree species, with larger C stocks in the forest floor of spruce stands compared to the mineral soil. Consistent differences in the bulk density of soils under each tree species are likely to be observed, pointing out the need to compare soil C stocks based on equal soil mass. The magnitude of the combined C stock in biomass and soil may increase with planting of spruce, however, we also expect an impact on C stability that will affect the overall mitigation effect of this measure.

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Sustainable development of hydropower demands a holistic view of potential impacts of water level regulation (WLR) on reservoir ecosystems. Most environmental studies of hydropower have focused on rivers, whereas environmental effects of hydropower operations on reservoirs are less well understood. Here, we synthesize knowledge on how WLR from hydropower affects alpine lake ecosystems and highlight the fundamental factors that shape the environmental impacts of WLR. Our analysis of these impacts ranges from abiotic conditions to lower trophic levels and ultimately to fish. We conclude that the environmental effects are complex and case-specific and thus considering the operational regime of WLR (i.e. amplitude, timing, frequency, and rate of change) as well as the reservoir’s morphometry, geology and biotic community are prerequisites for any reliable predictions. Finally, we indicate promising avenues for future research and argue that recording and sharing of data, views and demands among different stakeholders, including operators, researchers and the public, is necessary for the sustainable development of hydropower in alpine lakes.

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Background and Aims Competitive crops are a central component of resource-efficient weed control, especially for problematic perennial weeds such as Elymus repens. Competition not only reduces total weed biomass, but denial of resources can also change the allocation pattern – potentially away from the underground storage organs that make perennial weeds difficult to control. Thus, the competition mode of crops may be an important component in the design of resource-efficient cropping systems. Our aim was to determine how competition from companion crops with different modes of competition affect E. repens biomass acquisition and allocation and discuss that in relation to how E. repens responds to different levels of light and nutrient supply. Methods Greenhouse experiments were conducted with E. repens growing in interspecific competition with increasing density of perennial ryegrass or red clover, or growing at three levels of both light and nutrient supply. Key ResultsElymus repens total biomass decreased with increasing biomass of the companion crop and the rate of decrease was higher with red clover than with perennial ryegrass, particularly for E. repens rhizome biomass. A reduced nutrient supply shifted E. repens allocation towards below-ground biomass while a reduced light supply shifted it towards shoot biomass. Red clover caused no change in E. repens allocation pattern, while ryegrass mostly shifted the allocation towards below-ground biomass, but the change was not correlated with ryegrass biomass. Conclusions The companion crop mode of competition influences both the suppression rate of E. repens biomass acquisition and the likelihood of shifts in E. repens biomass allocation.