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
In organic plant production, nitrogen (N) availability is often a growth-limiting factor. Under such conditions, off-farm waste-derived nutrient resources may be an alternative to meet the N demand. In this study, we described a production method for a shrimp shell (SS) pellet Product and evaluated the N fertiliser effect and N recovery efficiency (NRE) in a controlled climate pot experiment with potatoes. The experiment was set up with low, medium and high N levels of SS pellets in comparison with a standard mineral fertiliser (MF) at 9°C, 15°C and 21°C. In a separate study, we examined the loss of N as N2O from SS pellets in comparison with SS powder in a 100 days incubation experiment. The results documented the possibility to formulate a fertiliser pellet product from SS, and that SS pellets were an effective N fertiliser in potato at all Growth temperatures. Nevertheless, a slightly slower development and lower tuber yields than for MF indicated a delayed N-availability from SS pellet fertiliser. NRE after use of MF was around 90%, and about 70% for the different levels of SS pellets. The incubation experiment showed a higher rate of available N for SS powder than for pellets (67% and 39%, respectively) after 100 days of incubation at constant humidity and temperature. This difference was attributed to a lower degree of dissolved materials and a higher rate of denitrification and N2O emissions for pellets than for powder, probably caused by differences in physical properties, occurrence of anoxic hotspots and higher microbial activity around and inside the SS pellets.
Sammendrag
Legume-based cropping system and Brachiaria forage system could play a significant role in enhancing food and nutrition security and sustainable intensifications of African agriculture. To reveal this potential, a comprehensive review of literatures and assessment was performed using key indicators in relation to food and nutrition quality, agro-ecological services and socioeconomic benefits. The key indicators for legumes intercropping systems include: Grain yield, soil organic matter, food availability, nutritive values of legumes, maize and millets- based foods, proportion of income from crop sale and percentage of farmers aware and/or adopting intercropping. In the case of Brachiaria system, the forage biomass, milk yield, availability of milk, milk nutrition contents, income from Brachiaria grass and milk sale and people practising the Brachiaria technology were considered key indicators. Both systems showed positive impacts and contribute to a range of the United Nation’s sustainable development goals including 1, 2, 3, 12, 13 and 15 and other associated targets. Integrating legume-based cropping systems and Brachiaria forage system will enhance contributions of smallholder farmers to food and nutrition security. The necessary changes needed in technology, institutions and policies to upscale legume-based cropping systems and Brachiaria forage system were suggested. These changes include improved varieties, quality seeds, improved cultivation practices, market provision, effective extension and advisory services and support to the seed productions and distribution systems, among others. Yet, to fully tap the potentials of legume-based and Brachiaria forage systems sustainably and raise the profile of these climate smart systems, context specific research measures are necessary.
Sammendrag
Biochar has been shown to reduce nitrous oxide (N2O) emissions from soils, but the effect is highly variable across studies and the mechanisms are under debate. To improve our mechanistic understanding of biochar effects on N2O emission, we monitored kinetics of NO, N2O and N2 accumulation in anoxic slurries of a peat and a mineral soil, spiked with nitrate and amended with feedstock dried at 105 °C and biochar produced at 372, 416, 562 and 796 °C at five different doses. Both soils accumulated consistently less N2O and NO in the presence of high-temperature chars (BC562 and BC796), which stimulated reduction of denitrification intermediates to N2, particularly in the acid peat. This effect appeared to be strongly linked to the degree of biochar carbonisation as predicted by the H:C ratio of the char. In addition, biochar surface area and pH were identified as important factors, whereas ash content and CEC played a minor role. At low pyrolysis temperature, the biochar effect was soil dependent, suppressing N2O accumulation in the mineral soil, but enhancing it in the peat soil. This contrast was likely due to the labile carbon content of low temperature chars, which contributed to immobilise N in the mineral soil, but stimulated denitrification and N2O emission in the peat soil. We conclude that biochar with a high degree of carbonisation, high pH and high surface area is best suited to supress N2O emission from denitrification, while low temperature chars risk supporting incomplete denitrification.
Sammendrag
The use of blankets in horses is widespread in Northern Europe. However, horses are very adaptable to low temperatures and the practice is questioned because blankets may hamper heat dissipation at high temperatures and also disturb free movement. The aim of the current study was to gain information about horses’ own preferences for wearing or not wearing a blanket under different weather conditions during the seasons. 10 horses usually wearing blankets and 13 horses usually not wearing blankets were kept outside in their paddock for 2 h during different weather conditions. Then, these horses were tested for their preference for wearing blankets (see Mejdell et al., 2016). When only considering air temperature and not the impact of other weather factors, the horses preferred to have the blanket on in 80% and 90% of the test at t < -10 °C in horses usually wearing and not wearing blankets, respectively. As air temperature increased, the preference for keeping the blanket on decreased and at air temperatures > 20 °C, the horses preferred to remove the blanket in all the tests. According to the statistical model, the probability for choosing to have a blanket on increased with increasing wind speed, and also precipitation increased the probability for choosing to have a blanket on. Sunshine however, reduced the probability for choosing to wear a blanket.
Sammendrag
The genus Scapania comprises a group of leafy liverworts distributed throughout many bryophytic assemblages. While many Scapania species grow widely, some are assessed as endangered and appear to be specialists with distinct niche environments. Several are found only in alpine forest communities, inhabiting decaying logs in streams, typical of an environment that is threatened by both logging activity and changes to watercourses. Another species, S. nimbosa, has an unusual Oceanic-Montane distribution across Ireland, Scotland, Norway, China and Nepal. Since gemmae and sexual reproduction are absent the species is hypothesized to be primarily dispersed by fragmentation. In Norway S. nimbosa occupies an area of only 13 x 20 km, at altitudes between 300-980 m, and is frequently found with another more abundant asexual species, S. ornithopodioides. This makes S. nimbosa susceptible to local extinction through climate change or perhaps interspecific competition. Genomics is being increasingly used to infer demography and the evolutionary history of a species. Ascertaining levels of genetic variation can also contribute towards an effective conservation management plan. Besides, very little is known about the genomic organization and sexual determination in leafy liverworts. To generate new knowledge about the genus Scapania we sequenced the genomes of the sexual species S. nemorea (both male and female isolates), S. undulata (a single isolate), and several asexual S. ornithopodiodes and S. nimbosa isolates. Illumina paired-end (2x 300 bp) and Oxford Nanopore long reads were used to create genomic references. Initially organellar genomes were assembled, annotated and genetic variation was discovered. This revealed that variation is indeed present even for S. nimbosa and S. ornithopodioides at Norwegian sites. Next we focussed on creating a high quality nuclear reference genome for S. nemorea using the SPAdes assembler (v3.13). Qualities of each assembly and isolate were assessed with QUAST and BUSCO. While one assembly spans 202.6 Mb (10930 scaffolds; N50 of 66 Kb), other isolates of S. nemorea show larger assembled genome sizes and different Kmer distributions, consistent with the expected alternative sexual chromosome complement. We further analyse genomic synteny and diversity, but emphasize that difficulties in extracting DNA from herbarium specimens really hamper analysis.
Forfattere
Juraj Parajka Nejc Bezak John Burkhart Bjarki Hauksson Ladislav Holko Yeshewa Hundecha Michal Jenicek Pavel Krajčí Walter Mangini Peter Molnar Philippe Riboust Jonathan Rizzi Aynur Sensoy Guillaume Thirel Alberto ViglioneSammendrag
This study evaluates MODIS snow cover characteristics for large number of snowmelt runoff events in 145 catchments from 9 countries in Europe. The analysis is based on open discharge daily time series from the Global Runoff Data Center database and daily MODIS snow cover data. Runoff events are identified by a base flow separation approach. The MODIS snow cover characteristics are derived from Terra 500 m observations (MOD10A1 dataset, V005) in the period 2000–2015 and include snow cover area, cloud coverage, regional snowline elevation (RSLE) and its changes during the snowmelt runoff events. The snowmelt events are identified by using estimated RSLE changes during a runoff event. The results indicate that in the majority of catchments there are between 3 and 6 snowmelt runoff events per year. The mean duration between the start and peak of snowmelt runoff events is about 3 days and the proportion of snowmelt events in all runoff events tends to increase with the maximum elevation of catchments. Clouds limit the estimation of snow cover area and RSLE, particularly for dates of runoff peaks. In most of the catchments, the median of cloud coverage during runoff peaks is larger than 80%. The mean minimum RSLE, which represents the conditions at the beginning of snowmelt events, is situated approximately at the mean catchment elevation. It means that snowmelt events do not start only during maximum snow cover conditions, but also after this maximum. The mean RSLE during snowmelt peaks is on average 170 m lower than at the start of the snowmelt events, but there is a large regional variability.
Sammendrag
For plum production to be economically viable, dwarfing rootstocks are essential for establishing high-density orchards, which ensure easier management, lower production costs, and earlier yields. Performance of the semi-dwarfing plum rootstocks ‘Wavit’, ‘Ute’ (both clones of Prunus domestica), and the dwarfing ‘VVA-1’ (Krymsk®1) was compared against the industry standard, ‘St. Julien A’. Onto these rootstocks, scion cultivars ‘Excalibur’, ‘Reeves’, and ‘Valor’ were grafted and assessed in a replicated field trial in western Norway at 60° North. Trees were planted in spring 2006 and the ‘VVA-1’ rootstock in May 2007. Plants were all one-year-old whips, spaced 2.0×4.0 m apart and trained to a central leader as free spindles. Tree vigour, yield, fruit size, fruit quality, and yield efficiency were evaluated for eight subsequent years. Tree size was significantly influenced by the rootstock after eight years of growth. ‘VVA-1’ produced the smallest trees, about half the tree size of ‘St. Julien A’ as measured by trunk cross-sectional area. ‘Wavit’ and ‘Ute’ were similar in size to ‘St. Julien A’. All plum trees came into production slowly. On average the cultivars ‘Excalibur’ and ‘Reeves’ were harvested in mid-September and ‘Valor’ two weeks later. During the period 2011-2014, when trees were fully mature, ‘Reeves’ and ‘Valor’ grafted on the three semi-dwarfing rootstocks resulted in the highest yields tree-1. ‘VVA-1’ resulted in significantly lower yields for ‘Valor’. ‘Excalibur’ was the only cultivar in which ‘VVA-1’ significantly increased yield efficiency. Accumulated yield from 2011-2015 on ‘VVA-1’ was 0.52 kg cm-2 TCSA, 2.3 times more than on ‘St Julien A’. Fruit weight in ‘Excalibur’ and ‘Reeves’ was on average 57 and 62 g, respectively, and not affected by the different rootstocks. ‘Valor’ on ‘VVA-1’ showed a 10 g reduction in fruit weight compared to 59 g fruit weight on the other rootstocks. Fruit soluble solids were on average around 13 °Brix for ‘Excalibur’ and ‘Reeves’ and 16 °Brix for ‘Valor’ and did not differ significantly between trees on the different rootstocks tested. In conclusion, ‘St. Julien A’ was the most reliable semi-vigorous rootstock and resulted in the highest accumulated yields over the first eight years after planting and with favourable effects on fruit quality of all European plum cultivars evaluated. ‘VVA-1’ resulted in trees of low vigour which, especially with ‘Excalibur’, were more precocious and had higher yield efficiencies than all other rootstock scion combinations. If this rootstock is to be used it should be planted at a higher density per area than the semi-dwarfing rootstocks and on fertile soil with fertigation provided.
Forfattere
Jyrki Jauhiainen Jukka Alm Brynhildur Bjarnadottir Ingeborg Callesen Jesper R Christiansen Nicholas Clarke Lise Dalsgaard Hongxing He Sabine Jordan Vaiva Kazanavičiūtė Leif Klemedtsson Ari Laurén Andis Lazdiņš Aleksi Lehtonen Annalea Lohila Ainars Lupikis Ülo Mander Kari Minkkinen Åsa Kasimir Mats Olsson Paavo Ojanen Hlynur Óskarsson Bjarni D. Sigurdsson Gunnhild Søgaard Kaido Soosaar Lars Vesterdal Raija LaihoSammendrag
Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small resources, several methodologies and manually operated systems, which further involve different options for the detailed design of the measurement and data analysis protocols for deriving the annual flux. It would be beneficial to set certain guidelines for how to measure and report the data, so that data from individual studies could also be used in synthesis work based on data collation and modelling. Such synthesis work is necessary for deciphering general patterns and trends related to, e.g., site types, climate, and management, and the development of corresponding emission factors, i.e. estimates of the net annual soil GHG emission and removal, which can be used in GHG inventories. Development of specific emission factors also sets prerequisites for the background or environmental data to be reported in individual studies. We argue that wide applicability greatly increases the value of individual studies. An overall objective of this paper is to support future monitoring campaigns in obtaining high-value data. We analysed peer-reviewed publications presenting CO2, CH4 and N2O flux data for drained organic forest soils in boreal and temperate climate zones, focusing on data that have been used, or have the potential to be used, for estimating net annual soil GHG emissions and removals. We evaluated the methods used in data collection and identified major gaps in background or environmental data. Based on these, we formulated recommendations for future research.
Sammendrag
Vegetation optical properties have a direct impact on canopy absorption and scattering and are thus needed for modeling surface fluxes. Although plant functional type (PFT) classification varies between different land surface models (LSMs), their optical properties must be specified. The aim of this study is to revisit the “time-invariant optical properties table” of the Simple Biosphere (SiB) model (later referred to as the “SiB table”) presented 30 years ago by Dorman and Sellers (1989), which has since been adopted by many LSMs. This revisit was needed as many of the data underlying the SiB table were not formally reviewed or published or were based on older papers or on personal communications (i.e., the validity of the optical property source data cannot be inspected due to missing data sources, outdated citation practices, and varied estimation methods). As many of today's LSMs (e.g., the Community Land Model (CLM), the Jena Scheme of Atmosphere Biosphere Coupling in Hamburg (JSBACH), and the Joint UK Land Environment Simulator (JULES)) either rely on the optical properties of the SiB table or lack references altogether for those they do employ, there is a clear need to assess (and confirm or correct) the appropriateness of those being used in today's LSMs. Here, we use various spectral databases to synthesize and harmonize the key optical property information of PFT classification shared by many leading LSMs. For forests, such classifications typically differentiate PFTs by broad geo-climatic zones (i.e., tropical, boreal, temperate) and phenology (i.e., deciduous vs. evergreen). For short-statured vegetation, such classifications typically differentiate between crops, grasses, and photosynthetic pathway. Using the PFT classification of the CLM (version 5) as an example, we found the optical properties of the visible band (VIS; 400–700 nm) to fall within the range of measured values. However, in the near-infrared and shortwave infrared bands (NIR and SWIR; e.g., 701–2500 nm, referred to as “NIR”) notable differences between CLM default and measured values were observed, thus suggesting that NIR optical properties are in need of an update. For example, for conifer PFTs, the measured mean needle single scattering albedo (SSA, i.e., the sum of reflectance and transmittance) estimates in NIR were 62 % and 78 % larger than the CLM default parameters, and for PFTs with flat leaves, the measured mean leaf SSA values in NIR were 20 %, 14 %, and 19 % larger than the CLM defaults. We also found that while the CLM5 PFT-dependent leaf angle values were sufficient for forested PFTs and grasses, for crop PFTs the default parameterization appeared too vertically oriented, thus warranting an update. In addition, we propose using separate bark reflectance values for conifer and deciduous PFTs and demonstrate how shoot-level clumping correction can be incorporated into LSMs to mitigate violations of turbid media assumption and Beer's law caused by the nonrandomness of finite-sized foliage elements.
Forfattere
Mohammad Ramin Marcia Franco Michael Roleda Inga Marie Aasen Mårten Hetta Håvard SteinshamnSammendrag
Utilisable crude protein (uCP), methane (CH4) production and other fermentation parameters were analysed in vitro for a diet in which grass silage was replaced by different levels of seaweed protein fractions prepared from three seaweed species: Saccharina latissima, Alaria esculenta and Palmaria palmata. Ten fractions from these three species in which the protein content had been increased and the salt content reduced by simple processing were tested, with inclusion levels in the diet based on the nitrogen content of the fractions. Following an extraction procedure, four fractions from Saccharina latissima, three from Alaria esculenta and one from Palmaria palmata, were gradually included in the diet by replacing high quality silage with approximately 0, 0.15, 0.30 and 0.45 g/g DM, while two high-protein fractions of Palmaria palmata were tested at replacement levels of 0, 0.075, 0.15 and 0.225 g/g DM. To estimate fermentation parameters, 500 mg of each diet were incubated in bottles with 60 mL buffered rumen fluid. Estimated uCP increased linearly with increasing replacement rate of grass silage with seaweed protein fractions (from 158 g/kg DM to 206 g/kg DM on average for all fractions). Increasing protein fraction from the brown seaweed Saccharina latissima in the diet significantly increased true organic matter digestibility (OMD) (from on average 0.786 to 0.821). Organic matter digestibility decreased with increasing level of Alaria esculenta fractions (from on average 0.785 to 0.733), which also gave a linear decrease in CH4 production (from on average 45.3 to 38.5 mL/g organic matter). As a result of decreased CH4 production and OMD, total volatile fatty acid concentration decreased with increasing level of Alaria esculenta fractions (from on average 69.5 to 63.0 mmol/L). Thus, positive and species-specific effects of seaweed on estimated uCP and fermentation parameters were observed in vitro when protein fractions remaining after an extraction procedure on seaweed partly replaced grass silage in the feed ration.