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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.

2022

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Planted filters are often used to remove pesticides from runoff water. However, the detailed fate of pesticides in the planted filters still remains elusive. This hampers an accurate assessment of environmental risks of the pesticides related to their fate and thereby development of proper mitigation strategies. In addition, a test system for the chemical fate analysis including plants and in particular for planted filters is not well established yet. Therefore, we developed a microcosm test to simulate the fate of pesticide in planted filters, and applied 2-13C,15N-glyphosate as a model pesticide. The fate of 2-13C,15N-glyphosate in the planted microcosms over 31 day-incubation period was balanced and compared with that in the unplanted microcosms. The mass balance of 2-13C,15N-glyphosate turnover included 13C mineralization, degradation products, and the 13C and 15N incorporation into the rhizosphere microbial biomass and plants. We observed high removal of glyphosate (> 88%) from the water mainly due to adsorption on gravel in both microcosms. More glyphosate was degraded in the planted microcosms with 4.1% of 13C being mineralized, 1.5% of 13C and 3.8% of 15N being incorporated into microbial biomass. In the unplanted microcosms, 1.1% of 13C from 2-13C,15N-glyphosate was mineralized, and only 0.2% of 13C and 0.1% of 15N were assimilated into microbial biomass. The total recovery of 13C and 15N was 81% and 85% in planted microcosms, and 91% and 93% in unplanted counterparts, respectively. The microcosm test was thus proven to be feasible for mass balance assessments of the fate of non-volatile chemicals in planted filters. The results of such studies could help better manage and design planted filters for pesticide removal.

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Barnyard grass [Echinochloa crus-galli (L.) Beauv] is a competitive C4 weed species that is widely distributed throughout the world. Although it originated in warm climatic conditions, currently, it is found in Europe as far north as Norway. This study aimed to compare the phenological development of plants from different climatic conditions in varying environmental conditions. To represent the contrasting climatic conditions within Europe, seeds were collected in Norway and Italy, and distributed to the study participants, to be sown at 10 different sites as two common populations. In addition to that, seeds of two to three local populations were collected near each of the sites. The development of the plants was monitored in a pot experiment set up under field conditions. The time to reach heading in the first year of the experiment was 77.6% faster (ranging from 45.9 to 98.3% on average) in the Norwegian than in the Italian population. However, in the leaf development stage, the difference between the common populations was smaller by, 23.5% on average (0–46.7%) and was mostly not significant. Our results indicate that different E. crus-galli ecotypes, characterized by differences in their phenological development, evolved within the distribution area of this species in Europe. However, the early development of the plants progressed with negligible differences between populations. The findings reported here can be used to adapt existing models from one region to regions with different climatic conditions for use in decision support systems and for research into plant population dynamics.

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The rapid conversion of tropical rainforests into monoculture plantations of rubber (Hevea brasiliensis) in Southeast Asia (SEA) necessitates understanding of rubber tree physiology under local climatic conditions. Frequent fog immersion in the montane regions of SEA may affect the water and carbon budgets of the rubber trees and the plantation ecosystems. We studied the effect of fog on various plant physiological parameters in a mature rubber plantation in southwest China over 3 years. During the study period, an average of 141 fog events occurred every year, and the majority occurred during the dry season, when the temperature was relatively low. In addition to the low temperature, fog events were also associated with low vapor pressure deficit, atmospheric water potential, relative humidity and frequent wet-canopy conditions. We divided the dry season into cool dry (November-February) and hot dry (March-April) seasons and classified days into foggy (FG) and non-foggy (non-FG) days. During the FG days of the cool dry season, the physiological activities of the rubber trees were suppressed where carbon assimilation and evapotranspiration showed reductions of 4% and 15%, respectively, compared to the cool dry non-FG days. Importantly, the unequal declines in carbon assimilation and evapotranspiration led to enhanced crop water productivity (WPc) on cool dry FG days but insignificant WPc values were found between FG and non-FG days of the hot dry season. Our results suggest that, by regulating plant physiology, fog events during the cool dry season significantly reduce water demand and alleviate water stress for the trees through improved WPc.

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Historically, the autumn dynamics of deciduous forest trees have not been investigated in detail. However, autumn phenological events, like onset of loss of canopy greenness (OLCG), onset of foliar senescence (OFS) and cessation of wood growth (CWG), have an important impact on tree radial growth and the entire ecosystem's seasonal dynamics. Here, we monitored the leaf and wood phenological events of silver birch (Betula pendula) at four different sites in Ås, southeastern Norway: (a) a natural mature stand, (b) a plantation on former agricultural ground, (c) young natural trees, and (d) young trees in pots under different fertilization levels. The study took place over four consecutive years (from 2017 to 2020), with a particular focus on 2018, a year in which there was a severe summer drought, and the next year, 2019, which featured more normal conditions. First, we provided a description of birch phenology within its mid-north distributional. Second, we showed that drought advanced CWG by about 5 to 6 weeks and it delayed OLCG and OFS up to 30 days. Third, we observed an unexpected advance in OLCG in 2019 compared to 2018 (30 days) and 2020 (14 days). OFS presented similar dynamics as OLCG, whereas CWG was advanced only in 2018. These findings might indicate lag-effects of severe drought on the next year autumn leaf phenology but not on wood growth. On the other hand, the comparison between the natural stand and the plantation showed that, under drought conditions, wood growth is more sensitive to site fertility than autumn leaf phenology. In summary, our study elucidated the autumn dynamics of an important deciduous forest species in the northern temperate zone and showed unexpected impacts of a severely dry and warm summer on the current and next year leaf phenology.

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Microalgal biomass is widely studied for its possible application in food and human nutrition due to its multiple potential health benefits, and to address raising sustainability concerns. An interesting field whereby to further explore the application of microalgae is that of beer brewing, due to the capacity of some species to accumulate large amounts of starch under specific growth conditions. The marine species Tetraselmis chui is a well-known starch producer, and was selected in this study for the production of biomass to be explored as an active ingredient in beer brewing. Cultivation was performed under nitrogen deprivation in 250 L tubular photobioreactors, producing a biomass containing 50% starch. The properties of high-starch microalgal biomass in a traditional mashing process were then assessed to identify critical steps and challenges, test the efficiency of fermentable sugar release, and develop a protocol for small-scale brewing trials. Finally, T. chui was successfully integrated at a small scale into the brewing process as an active ingredient, producing microalgae-enriched beer containing up to 20% algal biomass. The addition of microalgae had a noticeable effect on the beer properties, resulting in a product with distinct sensory properties. Regulation of pH proved to be a key parameter in the process.

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Aquaculture industry is one of the world’s fastest and largest growing food producing sector. Most importantly, the usage of fish meal in aquaculture has been replaced with alternate protein sources due to their production cost, demand of raw materials and various environmental issues. The insect black soldier fly (Hermetia illucens) larval (BSFL) meal is being recognized as a feed ingredient in aquafeeds for their protein rich content similar to fish meal (FM). BSFL meal has been utilized as a fish meal or soy meal substitution in aquaculture to improve the nutrition. The culture of H. illucens larvae can be achieved using various biodegradable wastes and converted into a valuable biomass. In addition, the proximate analysis of H. illucens has been analyzed for its multifaceted role in poultry, cattle feed preparation and human consumption. The effectiveness of BSFL diet was analyzed for final body weight (FBW), specific growth rate (SGR), feed conversion ratio (FCR), feed intake (FI), feed efficiency (FE) and survival (SUR) of different fish and shrimp used as an experimental models with FM as the control diet. However, there is no comprehensive review available on the BSFL as an alternate protein source in aquaculture till date. Hence, the present review aimed to evaluate the feasible role of BSFL in feed, its sustainable production and challenges of BSFL meal in aquaculture sector along with their merits and demerits.

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Som en del av prosjektet Presisjonshektaren ved NIBIO Senter for Presisjonsjordbruk har det gjennom 2021 og 2022 blitt utført et demonstrasjonsforsøk hvor det ble prøvd ulike verktøy til jordkartlegging på et tilsynelatende homogent skifte gjennom en sesong. Denne rapporten oppsummerer dette arbeidet ved å beskrive resultatet fra kartleggingen og ser på sammenhenger mellom kartleggingsresultater og avlingsnivå. Resultatene viser at også innenfor et skifte som ser homogent ut, finnes det en god del variasjon på grunn av topografi (Figur 2) og forskjeller i jordegenskaper (Figur 8 - Figur 11) som kan føre til en betydelig variasjon i avling og proteininnhold (Figur 20 og Figur 21). Dette viser at dersom man skal kartlegge jorda som basis for presisjonstildeling av innsatsfaktorer, kan det være verdt å vurdere å ta jordprøver noe tettere enn den generelle anbefalingen. I dette forsøket viste høsteprøvene et spenn i kornavling tilsvarende 560-800 kg per daa minimum. Proteininnholdet varierte fra 11,2 til 13 %. Siden dette forsøket ble gjennomført som et ettårig forsøk uten gjentak, er det ikke mulig å konkludere med noen årsakssammenheng mellom de forskjellige variablene som er målt. Det er likevel observert interessante samvariasjoner mellom forskjellige typer kartlegging. Det kan være interessant å gjøre mer detaljerte forsøk for å undersøke disse nærmere på et senere tidspunkt. Ved konvensjonell, uniform dyrkingspraksis, vil hele skiftet behandles likt ved for eksempel gjødsling og jordarbeiding. Dette fører til at ikke alle områder blir behandlet etter behov og potensiale. Ved homogen gjødsling vil noen områder få mer gjødsel enn nødvendig. Dette reduserer utnyttelsen av innsatsfaktorene og kan føre til økt miljøbelastning og kostnader. Samtidig vil andre områder få for lite gjødsel, noe som kan begrense avlingspotensialet og produksjonseffektiviteten. Omfanget av variasjonen i dette forsøket illustrerer derfor behovet for stedspesifikk behandling. Med høye priser på innsatsfaktorer er det et stort innsparingspotensial i å behandle de ulike områdene ut fra behov og potensiale. Det finnes mange muligheter for kartlegging av åkeren, og gårdbrukeren møter mange ulike tilbud. Det er svært viktig at gårdbrukeren før hen benytter seg av et slikt tilbud ber om dokumentasjon på kvalitet og kalibrering for norske forhold. Ved omfattende kartlegging genereres også store mengder data som må ivaretas på en god måte for å kunne være til nytte for bonden. Som en del av arbeidet med Presisjonshektaren er det også utarbeidet en oversikt over forskjellige såkalte «Farm Management Information Systems» (FMIS) – informasjonsstyringssystemer for gårdsbruk (NIBIO Rapport – FMIS for norske gårdbrukere).) Et ettårig forsøk slik som det som er gjennomført her gir ikke muligheter for å konkludere om hvilken kartleggingsmetode som egner seg best. Resultatene og erfaringen fra det første året med forsøk på ‘Presisjonshektaren’ viser behovet for utvidet forskning på praktisk anvendelse av metodene for kartlegging for å prøve metodene gjennom flere sesonger og på ulike plasser for å også dekke variasjon i jordtype og klimatiske forhold. NIBIO driver med en rekke spennende forsøk innom presisionslandbruk i grensesnittet mellom agronomi, jordfag, plantedyrking og teknologi og dette blir også tema i nye forsøk i tida framover. Følg med på NIBIO’s aktivitet innenfor fagområdet: www.nibio.no https://precisionag.no/nb/hjem/

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Kelp forests in the North Atlantic are at risk of decline at their warm temperature distribution margins due to anthropogenic temperature rise and more frequent marine heat waves. To investigate the thermal adaptation of the cold-temperate kelp Laminaria digitata, we sampled six populations, from the Arctic to Brittany (Spitsbergen, Tromsø, Bodø [all Norway], Helgoland [Germany], Roscoff and Quiberon [both France]), across the species’ entire distribution range, spanning 31.5° latitude and 12-13°C difference in mean summer sea surface temperature. We used pooled vegetative gametophytes derived from several sporophytes to approximate the genetic diversity of each location. Gametophytes were exposed to (sub-) lethal high (20-25°C) and (sub-) optimal low (0-15°C) temperature gradients in two full-factorial, common-garden experiments, subjecting subsets of populations from different origins to the same conditions. We assessed survival of gametophytes, their ability to develop microscopic sporophytes, and subsequent growth. We hypothesized that the thermal performance of gametophytes and microscopic sporophytes corresponds to their local long-term thermal history. Integrated gametophyte survival revealed a uniform upper survival temperature (UST) of 24°C among five tested populations (Tromsø to Quiberon). In contrast, following two weeks of thermal priming of gametophytes at 20-22°C, sporophyte formation at 15°C was significantly higher in southern populations (Quiberon and Roscoff) compared to the high-latitude population of Tromsø. Between 0-15°C, survival of the Arctic population (Spitsbergen) was negatively correlated with increasing temperatures, while the southern-most population (Quiberon) showed the opposite. Thus, responses of survival at low, and sporophyte formation at high temperatures, support the concept of local adaption. On the other hand, sporophyte formation between 0-15°C peaked at 6-9°C in the Quiberon and at 9-12°C in the Spitsbergen population. Sporophyte growth rates (GR) both in length and width were similar for Spitsbergen, Tromsø and Quiberon; all had maximum GRs at 12-15°C and low GRs at 0-6°C. Therefore, responses of sporophyte formation and growth at low temperatures do not reflect ecotypic adaptation. We conclude that L. digitata populations display trait-dependent adaptation, partly corresponding to their local temperature histories and partly manifesting uniform or unpredictable responses. This suggests differential selection pressures on the ontogenetic development of kelps such as L. digitata.

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Forest management is an important tool for GHG mitigation by representing three carbon pools: living biomass, forest soil, and wood-based products. Additionally, increasing attention has been given to the potential for wood products to substitute fossil-intensive products as a climate mitigation strategy. The goal of this paper is to analyse the theoretical GHG effects of fully replacing four common non-wood products with wood-based products of ‘low’ and ‘high’ technology options that have a similar functionality: (1) Spruce particle board substituting polyurethane (PU) foam insulation board; (2) spruce cross-laminated timber beam (CLT) substituting steel beam; (3) birch energy wood substituting electric heating; and (4) birch plywood substituting plaster board. The analysis was based on forestry in Western Norway as a case study, where forests typically consist of naturally generated birch and expanding areas of planted Norway spruce. In this study we compare wood products derived from paired stands of Norway spruce and downy birch. The analysis showed that spruce gave a higher theoretical substitution effect relative to birch for the selected pairs of woody and non-woody products. CLT substituting steel beam gave the highest substitution effect, approximately 15% higher than particle board substituting PU foam board. The theoretical substitution effect in mass units of carbon per kg wood product for the two spruce wood products was approximately 17 times higher relative to substituting Norwegian hydro energy-based electric heating, whereas plywood substituting plaster board may in fact increase GHG emissions. As the gross emissions were relatively similar for the birch plywood and the spruce particle board, the major substitution effect was related to the avoided emission of the non-woody product rather than to the tree species per se. The paper concludes that the choice of product to be substituted was the key factor that determined the final substitution effects. Furthermore, the study showed that transportation was the single most important factor that affected the emissions between planting and delivery of the timber at production gate. The analysis enables informed decisions related to CO2-emissions at the various steps from tree planting to wood conversion, and underline the importance of informed decision related to the choice of substitution products.

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Heterogeneity of structure can increase mechanical stability, stress resistance and resilience, biodiversity and many other functions and services of forest stands. That is why many silvicultural measures aim at enhancing structural diversity. However, the effectiveness and potential of structuring may depend on the site conditions. Here, we revealed how the stand structure is determined by site quality and results from site-dependent partitioning of growth and mortality among the trees. We based our study on 90 mature, even-aged, fully stocked monocultures of Scots pine (Pinus sylvestris L.) sampled in 21 countries along a productivity gradient across Europe. A mini-simulation study further analyzed the site-dependency of the interplay between growth and mortality and the resulting stand structure. The overarching hypothesis was that the stand structure changes with site quality and results from the site-dependent asymmetry of competition and mortality. First, we show that Scots pine stands structure across Europe become more homogeneous with increasing site quality. The coefficient of variation and Gini coefficient of stem diameter and tree height continuously decreased, whereas Stand Density Index and stand basal area increased with site index. Second, we reveal a site-dependency of the growth distribution among the trees and the mortality. With increasing site index, the asymmetry of both competition and growth distribution increased and suggested, at first glance, an increase in stand heterogeneity. However, with increasing site index, mortality eliminates mainly small instead of all-sized trees, cancels the size variation and reduces the structural heterogeneity. Third, we modelled the site-dependent interplay between growth partitioning and mortality. By scenario runs for different site conditions, we can show how the site-dependent structure at the stand level emerges from the asymmetric competition and mortality at the tree level and how the interplay changes with increasing site quality across Europe. Our most interesting finding was that the growth partitioning became more asymmetric and structuring with increasing site quality, but that the mortality eliminated predominantly small trees, reduced their size variation and thus reversed the impact of site quality on the structure. Finally, the reverse effects of mode of growth partitioning and mortality on the stand structure resulted in the highest size variation on poor sites and decreased structural heterogeneity with increasing site quality. Since our results indicate where heterogeneous structures need silviculture interventions and where they emerge naturally, we conclude that these findings may improve system understanding and modelling and guide forest management aiming at structurally rich forests.