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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.

2024

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Wood-decay fungi are adapted to growth under different climate conditions and on various host tree species, but little is known about intraspecific variation in growth, substrate specificity and decay rates under different climatic conditions. Such knowledge is relevant to understand how wood-decay fungi will respond to climate change. Here, we investigate whether populations of the widespread brown-rot fungus Fomitopsis pinicola grow at different rates under different temperatures and water availabilities and whether the decay rate of the two wood substrates, Alnus incana and Picea abies, differs across populations. We isolated 72 cultures from fruit bodies collected in nine geographic localities across Norway, representing different climate conditions and substrates. We conducted in vitro growth experiments to assess the level of intraspecific phenotypic variability in temperature-dependent growth. All populations showed a strong but similar response in mycelial growth rates to different temperatures and water potentials. There were no consistent differences between populations in growth rates across temperatures, but larger variation between populations at the higher temperatures. Similarly, we observed no significant differences in wood decay rates across the nine populations and no signs of substrate specific adaptation to P. abies and A. incana. Our results indicate that local adaptation to different climates or substrates, as revealed by in vitro growth experiments, has to a limited extent, taken place during the few thousand years Fomitopsis pinicola has been present in this area.

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The importance of phosphorus (P) in regulating ecosystem responses to climate change has fostered P-cycle implementation in land surface models, but their CO2 effects predictions have not been evaluated against measurements. Here, we perform a data-driven model evaluation where simulations of eight widely used P-enabled models were confronted with observations from a long-term free-air CO2 enrichment experiment in a mature, P-limited Eucalyptus forest. We show that most models predicted the correct sign and magnitude of the CO2 effect on ecosystem carbon (C) sequestration, but they generally overestimated the effects on plant C uptake and growth. We identify leaf-to-canopy scaling of photosynthesis, plant tissue stoichiometry, plant belowground C allocation, and the subsequent consequences for plant-microbial interaction as key areas in which models of ecosystem C-P interaction can be improved. Together, this data-model intercomparison reveals data-driven insights into the performance and functionality of P-enabled models and adds to the existing evidence that the global CO2-driven carbon sink is overestimated by models.

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Potato production faces major challenges from inadequate soil fertility, and nematode infestation, yet synthetic fertilizers and nematicides are costly and harmful to the environment. This study explored the potential of chitin-fortified black soldier fly-composted organic fertilizer (BSFCOF) as a multipurpose organic fertilizer amendment for enhancing potato yield and suppressing potato cyst nematodes (PCN). The BSFCOF was applied at a rate equivalent to 150 kg N ha-1 and fortified with chitin from black soldier fly pupal exuviae at inclusion rates equivalent to 0.5, 1, 2, 3, 4 and 5% chitin. Data were collected on potato growth characteristics, PCN population densities, and soil chemical properties for two growing cycles. Results showed that chitin fortified BSFCOF significantly improved potato growth parameters, chlorophyll concentration, marketable tuber yield and number of marketable tubers. The marketable tuber yield achieved using chitin-fortified BSFCOF was 70 – 362%, and 69 – 238% higher than the values achieved using unfertilized soil during the first and second growing cycles, respectively. Soil amendment with chitin-fortified BSFCOF significantly reduced the number of cysts per 200 g soil-1, number of eggs and J2 per cyst-1, eggs g-1 soil and reproduction rate by 32 – 87%, 9 – 92%, 31– 98% and 31 – 98%, respectively. The PCN suppression increased with chitin inclusion rates. There were significantly higher values for soil pH, ammonium nitrogen, nitrate nitrogen, available phosphorus, calcium, magnesium, potassium, and cation exchange capacity in soil amended with BSFCOF compared to unamended soil. This study demonstrates that BSFCOF fortified with 5% chitin is an effective soil enhancer with multiple benefits, including improved soil fertility, potato performance, and effective management of potato cyst nematodes.

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Trials were carried out in apple orchards of Emilia-Romagna and Trentino-Alto Adige in northern Italy to investigate the effects of sprinkler irrigation on possible reduction in inoculum and subsequent disease pressure of Venturia inaequalis, the ascomycete causing apple scab. In spring, volumetric spore traps were placed above apple leaf litter containing pseudothecia with ascospores of the fungus. Pseudothecia matured more rapidly in irrigated plots, and 95% of the total number of spores trapped in a season was reached on average 164 degree days (base temperature 0°C) earlier in irrigated compared with nonirrigated plots. On average for seven location/year combinations, more than 50% of the ascospores were trapped following irrigations carried out for 2 h on sunny days before a forecasted rainfall. Subsequently, a much lower number of spores were trapped on rainy days following irrigation. Field trials with scab-susceptible apple cultivars were carried out in the two regions to evaluate the efficacy of sprinkler irrigation on disease. Irrigated and nonirrigated plots were either treated with different fungicide control strategies or not treated. Irrigation significantly reduced the incidence of apple scab at both sites, and the overall number of infected leaves and fruit was reduced by more than 50%. Midday sprinkler irrigation can significantly reduce the inoculum pressure of V. inaequalis in apple orchards. This may be a sustainable management strategy, especially in areas with extended dry periods.

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Six seed mixtures differing in number of species and their proportion of timothy (Phleum pratense L.) were tested during three/four production (ley) years in replicated field experiments at three climatically different sites in Norway; one a mountainous inland site at 61° N (Løken) and two in coastal environments, at 61° N (Fureneset) and 65° N (Tjøtta). There were significant differences in forage accumulation (FA) and digestible forage accumulation (DFA) between the three sites. There was a significant FA decline from the third to the fourth ley year for mixtures containing timothy, but not for mixtures without timothy. Estimated interannual FA- stability was higher for timothy-based seed mixtures than for mixtures without timothy at the inland site, but FA-stability was lower at the coastal sites. In the third-year herbage of timothy-based mixtures at the inland site consisted almost solely of timothy, whereas at the coastal sites meadow fescue (Festuca pratensis Huds.) and especially tall fescue (F. arundinacea Schreb.) dominated. In seed mixtures without timothy, cocksfoot (Dactylis glomerata L.) suppressed other species at the inland site, whereas at the coastal sites, tall fescue and ryegrasses (Lolium spp.) were the dominant species in the third-year herbage. Length of growing season and site-specific growing conditions were important drivers for the observed species changes. Timothy can thus be recommended for ley establishment at sites where the growing season is short (<4 months) and plant growth is intensive, but under conditions with a longer growing season it needs to be sown in mixtures with grass species that surpass the regrowth capacity of timothy.

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The food system significantly impacts the environment and society. This study examined a shift from a continuation of the current trend (policy as usual scenario) towards a biomass value hierarchy scenario, which focused on optimizing land and biomass use and rethinking the role of livestock production. The biomass value hierarchy was based on circular economy principles, the waste hierarchy, and national self-sufficiency, which eliminated feed import and redistributed protein sources in the diet. A Multi-Criteria Decisions Analysis (MCDA) framework was used to assess the two scenarios across four sustainability dimensions: environmental, social, economic and policy. Environmental and social impacts were analysed using life cycle assessment methodology, while economic and policy implications were explored using partial equilibrium modelling, with the Norwegian food system as a case study. The results for the environmental dimension indicated that, compared to the policy as usual scenario, the biomass value hierarchy reduced environmental impacts by 8% to 18% across the indicators, including climate change, acidification, particulate matter, terrestrial eutrophication and occupation of arable land. Social impacts also improved in categories with the highest social risks, such as equal opportunities for workers, health and safety for farmers, cultural heritage, food security, fair competition, and promoting social responsibility. Contrarily, indicators within the economic dimension revealed reduced profitability, and results within the policy dimension showed a considerable increase in required subsidies, border measures and governmental restrictions on consumption. The study findings indicate that an environmentally and socially sustainable food system is feasible but requires significant political and economic support. Additionally, the study highlights the value of using MCDA when combining different research methods in cross-disciplinary assessments. These results underscore the need for a societal debate on acceptable levels of political intervention and the role of consumers and taxpayers in shaping the future food system.

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Aims We introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions. Results ReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun-Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020. Conclusions ReSurveyEurope is a new resource to address a wide range of research questions on fine-scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well-established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.

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Large clear-cut areas as a consequence of drought and bark beetle infestations necessitate extensive replanting efforts in German forests, leading to an increased interest in efficient planting systems. In addition to manual planting, mechanized and semi-mechanized systems utilizing surplus forest machine capacities available after completion of salvage logging operations are likely required for timely reforestation of the clear-cut areas. A semi-mechanized system utilizing a standard forwarder with a grapple-actuated soil borer for both, the transport of planting material and the preparation of planting pits, combined with two workers carrying out manual planting, was investigated in a time-and-motion study. The frequency method was used after video recording of a planting operation that covered an area of approximately 1.2 hectares. A total of 815 alder saplings (Alnus glutinosa L.) with heights of 1.2–1.5 m were planted. Observed productivity was 93 saplings per system work hour (SWH). With additional placement of stakes for stabilizing the plants, the productivity decreased to 42 saplings per SWH. While directly comparable results were not found in the literature, available productivity figures of purely manual planting systems do not suggest an increased productivity of this semi-mechanized system. Considering ergonomics, however, forwarder utilization provides reduced workload not only in plant hole preparation but also with material transport and clearing of planting spots. Both the ergonomic aspects of the system and, in particular, the suitability of the soil borer for different soil textures should be further investigated.

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This study evaluated 22 spring-type faba bean cultivars in the main areas for cultivation of faba bean in Norway to assess the variation of 14 faba bean traits due to cultivar (G), environment (E), and their interaction (G × E), and to assess their stability across environments by using the additive main effects and multiplicative interaction (AMMI) analysis and coefficient of variation (CV). Significant G, E, and G × E effects were found for most traits, with environment accounting for much of the variance in yield and the growing degree days (GDD) to different developmental stages. Yield was highly correlated with thousand kernel weight (TKW) and GDD to BBCH 89 (maturation). The stability of the cultivars was studied for yield, TKW, and GDD to BBCH 89. Stability analysis using the AMMI stability value, yield stability index, CV, and the average sum of ranks identified Birgit, Stella, Bobas, and Macho as the most stable high-yielding cultivars across environments, achieving a mean yield of 6–6.4 tons ha−1. Bobas, Macho, Stella, and Yukon had the most stable TKW (612–699 g) and Bobas, Capri, Trumpet, and Vertigo were the most stable regarding GDD to BBCH 89 (1257°C days, with a base temperature of 5°C). These stable cultivars can be utilized in breeding programs to achieve high and stable faba bean yield in the main growing areas of Norway and other Nordic-Baltic countries.

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Increasing planting densities and nitrogen (N) application rates are two practices commonly used in high-yield maize (Zea mays L.) production systems to increase crop yield, but have resulted in lower N use efficiency, increased lodging, and negative environmental problems. Crop sensing-based precision N management (PNM) strategies have been developed to optimize maize yield, N use efficiency, and reduce environmental footprints, however, PNM strategies to balance grain yield and lodging risks are still very limited. The objectives of this study were to: (1) propose a N nutrition index (NNI)-based algorithm for in-season estimation of maize N demand; and (2) develop a sensor-based PNM strategy to balance grain yield and lodging risk for maize. Field experiments were conducted in Northeast China from 2017 to 2019, using a split-plot design with three planting densities (5.5, 7.0 and 8.5 plants m−2) as main plots and six N rates (0–300 kg ha−1) as subplots. Based on previous studies, a leaf fluorescence sensor Dualex 4 good for estimating plant N concentration and a canopy reflectance sensor Crop Circle ACS 430 good for estimating plant aboveground biomass were used to estimate maize NNI and predict lodging risk. Total N rates to achieve low lodging risk were determined based on wind velocity causing maize stalk lodging and historical actual natural wind speed, as well as the response of a lodging risk indicator (stem failure moment, Bs) to N supply. In-season side-dress N rates were determined based on theoretical amount of preplant N fertilizer estimated using NNI and a target total N rate. The final recommended sidedress N rates were adjusted based on the sensor-predicted lodging risk. The results indicated that NNI could be used for estimating the theoretical amount of preplant N fertilizer required to reach the current N status. It’s feasible to estimate maize side-dress N demand based on the difference of a target total N rate (to achieve an optimal grain yield or low lodging risk) and the current theoretical N supply. Total N rate to ensure low lodging risk was suggested to be adopted under low and medium planting densities. Medium planting density of 70,000 plants ha−1 matched with the corresponding optimal N rate would be recommended for the study area to balance economic return and lodging risk. In general, high planting density is not recommended because it has high lodging risk. More studies are needed to further improve the developed crop sensing-based PNM strategy with more site-years of data and multi-source data fusion using machine learning models for practical on-farm applications.