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
Forfattere
Simon Weldon Bert van der Veen Eva Farkas Nazli Pelin Kocatürk Schumacher Alba Dieguez-Alonso Alice Budai Daniel RasseSammendrag
Sorption of nutrients such as NH4+ is often quoted as a critical property of biochar, explaining its value as a soil amendment and a filter material. However, published values for NH4+ sorption to biochar vary by more than 3 orders of magnitude, without consensus as to the source of this variability. This lack of understanding greatly limits our ability to use quantitative sorption measurements towards product design. Here, our objective was to conduct a quantitative analysis of the sources of variability, and infer which biochar traits are more favourable to high sorption capacity. To do so, we conducted a standardized remodelling exercise of published batch sorption studies using Langmuir sorption isotherm. We excluded studies presenting datasets that either could not be reconciled with the standard Langmuir sorption isotherm or generated clear outliers. Our analysis indicates that the magnitude of sorption capacity of unmodified biochar for NH4+ is lower than previously reported, with a median of 4.2 mg NH4+ g−1 and a maximum reported sorption capacity of 22.8 mg NH4+ g−1. Activation resulted in a significant relative improvement in sorption capacity, but absolute improvements remain modest, with a maximum reported sorption of 27.56 mg NH4+ g−1 for an activated biochar. Methodology appeared to substantially impact sorption estimates, especially practices such as pH control of batch sorption solution and ash removal. Our results highlight some significant challenges in the quantification of NH4+ sorption by biochar and our curated data set provides a potentially valuable scale against which future estimates can be assessed.
Forfattere
Vindhya Basnayaka Jayanga T. Samarasinghe Miyuru Gunathilake Nitin Muttil Dileepa C. Hettiarachchi Amila Abeynayaka Upaka RathnayakeSammendrag
River meandering and anabranching have become major problems in many large rivers that carry significant amounts of sediment worldwide. The morphodynamics of these rivers are complex due to the temporal variation of flows. However, the availability of remote sensing data and geographic information systems (GISs) provides the opportunity to analyze the morphological changes in river systems both quantitatively and qualitatively. The present study investigated the temporal changes in the river morphology of the Deduru Oya (river) in Sri Lanka, which is a meandering river. The study covered a period of 32 years (1989 to 2021), using Landsat satellite data and the QGIS platform. Cloud-free Landsat 5 and Landsat 8 satellite images were extracted and processed to extract the river mask. The centerline of the river was generated using the extracted river mask, with the support of semi-automated digitizing software (WebPlotDigitizer). Freely available QGIS was used to investigate the temporal variation of river migration. The results of the study demonstrated that, over the past three decades, both the bend curvatures and the river migration rates of the meandering bends have generally increased with time. In addition, it was found that a higher number of meandering bends could be observed in the lower (most downstream) and the middle parts of the selected river segment. The current analysis indicates that the Deduru Oya has undergone considerable changes in its curvature and migration rates.
Forfattere
Darius Kviklys Jonas Viškelis Mindaugas Liaudanskas Valdimaras Janulis Kristina Laužikė Giedrė Samuolienė Nobertas Uselis Juozas LanauskasSammendrag
Modern apple orchard systems should guarantee homogeneity of fruit internal and external qualities and fruit maturity parameters. However, when orchards reach productive age, a variation of these parameters takes place and mostly it is related to uneven light distribution within the tree canopy. The aim of the study was to evaluate the canopy position’s effect on fruit internal and external quality parameters. This is the first study where all the main fruit quality and maturation parameters were evaluated on the same trees and were related to the light conditions and photosynthetic parameters. Four fruit positions were tested: top of the apple tree, lower inside part of the canopy, and east and west sides of the apple tree. Fruit quality variability was significant for fruit size, blush, colour indices, total sugar content, dry matter concentration, accumulation of secondary metabolites and radical scavenging activity. Fruit position in the canopy did not affect flesh firmness and fruit maturity parameters such as the starch index, Streif index and respiration rate. At the Lithuanian geographical location (55°60′ N), significantly, the highest fruit quality was achieved at the top of the apple tree. The tendency was established that apple fruits from the west side of the canopy have better fruit quality than from the east side and it could be related to better light conditions at the west side of the tree. Inside the canopy, fruits were distinguished only by the higher accumulation of triterpenic compounds and higher content of malic acid. Light is a main factor of fruit quality variation, thus all orchard management practices, including narrow two-dimensional tree canopies and reflecting ground covers which improve light penetration through the tree canopy, should be applied.
Sammendrag
Clopyralid is a systemic herbicide used in oilseed rape and other crops. It was found in Danish honey from 2016 in concentrations exceeding the maximum residue level (MRL) of 0.05 mg kg−1. About 50% of the Danish honey is based on nectar from winter oilseed rape. In 2019 and 2020, winter oilseed rape fields were sprayed with clopyralid just before the assigned spraying deadline. At flowering, nectar and pollen samples were collected and the content of clopyralid was measured. Honey and pollen samples were also collected from beehives next to ten conventional winter oilseed rape fields sprayed with clopyralid. Clopyralid was found in nectar and pollen from the experimental fields, and in honey and pollen from beehives next to the conventional fields. For most samples the content in nectar and honey exceeded the MRL. The concentrations found, may not pose any health risk for consumers, as the MRL is based on the original detection limit and not on toxicological tests. However, it can have a significant economical consequence for the beekeepers, who are not allowed to sell the honey if the concentration of clopyralid exceeds 0.1 mg kg−1. Reducing the acceptable applicable rate of clopyralid or implementing an earlier deadline for spraying of clopyralid may reduce the risk of contaminating bee food products. However, if it is not possible to obtain a satisfactory effect of clopyralid on the weed flora under these conditions, spraying with pesticides containing clopyralid should be restricted in winter oilseed rape. Determination of an MRL value based on toxicological tests might result in a higher value and make it acceptable selling the honey containing higher levels of clopyralid.
Forfattere
Aritz Royo-Esnal Andrea Onofri Donato Loddo Jevgenija Necajeva Peter K. Jensen Garifalia Economou Alireza Taab Agnieszka Synowiec Isabel M. Calha Lars Andersson Ahmet Uludag Ilhan Uremis Alistair J. Murdoch Kirsten TørresenSammendrag
Echinochloa crus-galli (L.) P. Beauv. is one of the most important weeds. It is distributed worldwide and has adapted to diverse habitats and climatic conditions. This study aimed to compare the emergence patterns of two populations of E. crus-galli from different environments at 11 locations across Europe and the Middle East. Seeds of the two populations were collected from maize in Italy and from spring barley in Norway and were then buried in soil in autumn 2015. In the spring of 2016, the soil was disturbed around the usual seedbed preparation date in each location and emergence was recorded. The soil was again disturbed a year later and emergence was recorded for a second season. Total emergence, the times of onset, end and to 50% emergence and the period between 25% and 75% of emergence were analysed by two-way ANOVA and principal components analysis. The Italian population showed a higher emergence than the Norwegian population in Southern locations, while the ranking was reversed in Northern locations. In almost all locations, a tendency to emerge earlier was recorded for the Norwegian population, but the periods from 25% to 75% emergence were similar for both populations. Total emergence, and the times of onset and end of emergence seemed to be mainly under genotypic (plus maternal) control, suggesting there were different temperature thresholds for seedling emergence in each population. Conversely, the duration of emergence seemed to be mainly under environmental control. This research confirms the high variability between populations and suggests the need to continue identifying key characteristics for the development of efficient models for seedling emergence in specific climates and/or latitudes.
Sammendrag
Acrylamide has become an important measure when looking at profitability and sustainability in the potato processing industry. Acrylamide is a possible carcinogenic which is formed in starchy foods during high-temperature cooking processes. Crisps and French fries made from processing potatoes are consumed by people of all ages and therefore the pressure on the industry has been large to reduce the acrylamide levels. In the ongoing project POTETFRIT (2019-2022), the aim is to reduce acrylamide content and improve product quality, profitability and sustainability in the production of Norwegian crisps and French fries. The aim will be reached through new knowledge about the interaction between potato quality and storage conditions. The effect of different temperature strategies including cold storage (5 ⁰C) and reconditioning at 15 ⁰C was tested in eight different varieties (Lady Claire, Kiebitz, Pirol, Lady Britta, Peik, Innovator, Zorba and Gullflaks). The importance of elevated CO2 levels in the potato store on product quality and acrylamide content, was studied in the same potato varieties and in tubers with different maturity levels. Storage conditions in 29 commercial potato stores was also studied, with attention to temperature conditions and CO2 levels in different stages of the storage season. The effect of different ventilation strategies was also studied. So far results show that the varieties L. Claire, Kiebitz and Gullflaks can be stored at low temperature levels without developing high sugar and acrylamide levels and dark fry colour and at the same time keeping sprouting at a low level. In the CO2 trials, none of the varieties tested showed elevated sugar and acrylamide levels when exposed to high CO2 levels (15000 ppm) and also in the commercial stores there was no correlation between high CO2 and high sugar levels.
Sammendrag
The large brown seaweeds (kelps) are potential sources of protein for animal feed. They have lower protein contents than most red and green algae, but due to potential for large-scale production, they may represent a significant future protein source. The impact of pH, temperature and polysaccharide-degrading enzymes on the solubility and extraction yields of protein from wet Saccharina latissima biomass was investigated. The protein solubility increased with increasing pH and reached maximum of 23% at pH 11, determined as total amino acids (TAA). The enzyme treatments increased the release of soluble compounds by 30–35%. The highest protein yield obtained was 19%, using a ratio of water to wet seaweed of 1:1 for extraction. Even if the yields can be increased by increasing the water amounts used for extraction, the majority of the protein would remain in the insoluble residue after separation. The strategy for production of a larger quantity of protein-enriched biomass was therefore to maintain the insoluble fraction as the product. A pilot scale production was carried out, also including the red algae Palmaria palmata. In total 750 kg S. latissima and 195 kg P. palmata were processed. The protein content in the product increased from 10 to 20% of dry weight (dw) for S. latissima and from 12 to 28% for P. palmata, with yields of 79 and 69%, respectively. The ash content was reduced from 44 to 26% and from 12 to 5% of dw, respectively, for the two species. The main protein loss was free amino acids, which constituted approximately 10% of TAA in the feedstocks. Less essential than non-essential amino acids were lost, thus, the essential amino acids were enriched in the product.
Sammendrag
The success of Phasmarhabditis hermaphrodita (Schneider) Andrássy (Rhabditida: Rhabditidae) as a biological control agent of molluscs has led to a worldwide interest in phasmarhabditids. However, scant information is available on the lifecycle development of species within the genus. In the current study, the development of P. hermaphrodita, Phasmarhabditis papillosa, Phasmarhabditis bohemica and Phasmarhabditis kenyaensis were studied using ex vivo cultures, in order to improve our understanding of their biology. Infective juveniles (IJs) of each species were added to 1 g of defrosted homogenized slug cadavers of Deroceras invadens and the development monitored after inoculated IJ recovery, over a period of eight–ten days. The results demonstrated that P. bohemica had the shortest development cycle and that it was able to produce first-generation IJs after eight days, while P. hermaphrodita, P. papillosa and P. kenyaensis took ten days to form a new cohort of IJs. However, from the perspective of mass rearing, P. hermaphrodita has an advantage over the other species in that it is capable of forming self-fertilizing hermaphrodites, whereas both males and females are required for the reproduction of P. papillosa, P. bohemica and P. kenyaensis. The results of the study contribute to the knowledge of the biology of the genus and will help to establish the in vitro liquid cultures of different species of the genus.
Sammendrag
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.
Forfattere
Jevgenija Necajeva Aritz Royo-Esnal Donato Loddo Peter Jensen Alireza Taab Agnieszka Synowiec Ahmet Uludag Ilhan Uremis Alistair Murdoch Anna Bochenek Andrea Onofri Kirsten TørresenSammendrag
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.