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.
2021
Authors
Elisabeth Pötzelsberger Martin M. Gossner Ludwig Beenken Anna Gazda Michal Petr Tiina Ylioja Nicola La Porta Dimitrios N. Avtzis Elodie Bay Maarten De Groot Rein Drenkhan Mihai-Leonard Duduman Rasmus Enderle Margarita Georgieva Ari Hietala Björn Hoppe Herve Jactel Kristjan Jarni Srđan Keren Zsolt Keseru Marcin Koprowski Andrej Kormuťák María Josefa Lombardero Aljona Lukjanova Vitas Marozas Edurad Mauri Maria Cristina Monteverdi Per Holm Nygaard Nikica Ogris Nicolai Olenici Christophe Orazio Bernhard Perny Glória Pinto Michael Power Radoslaw Puchalka Hans Peter Ravn Ignacio Sevillano Sophie Stroheker Paul Taylor Panagiotis Tsopelas Josef Urban Kaljo Voolma Marjana Westergren Johanna Witzell Olga Zborovska Milica ZlatkovicAbstract
For non-native tree species with an origin outside of Europe a detailed compilation of enemy species including the severity of their attack is lacking up to now. We collected information on native and non-native species attacking non-native trees, i.e. type, extent and time of first observation of damage for 23 important non-native trees in 27 European countries. Our database includes about 2300 synthesised attack records (synthesised per biotic threat, tree and country) from over 800 species. Insects (49%) and fungi (45%) are the main observed biotic threats, but also arachnids, bacteria including phytoplasmas, mammals, nematodes, plants and viruses have been recorded. This information will be valuable to identify patterns and drivers of attacks, and trees with a lower current health risk to be considered for planting. In addition, our database will provide a baseline to which future impacts on non-native tree species could be compared with and thus will allow to analyse temporal trends of impacts.
Abstract
Organisms use circadian rhythms to anticipate and exploit daily environmental oscillations. While circadian rhythms are of clear importance for inhabitants of tropic and temperate latitudes, its role for permanent residents of the polar regions is less well understood. The high Arctic Svalbard ptarmigan shows behavioral rhythmicity in presence of light-dark cycles but is arrhythmic during the polar day and polar night. This has been suggested to be an adaptation to the unique light environment of the Arctic. In this study, we examined regulatory aspects of the circadian control system in the Svalbard ptarmigan by recording core body temperature (Tb) alongside locomotor activity in captive birds under different photoperiods. We show that Tb and activity are rhythmic with a 24-h period under short (SP; L:D 6:18) and long photoperiod (LP; L:D 16:8). Under constant light and constant darkness, rhythmicity in Tb attenuates and activity shows signs of ultradian rhythmicity. Birds under SP also showed a rise in Tb preceding the light-on signal and any rise in activity, which proves that the light-on signal can be anticipated, most likely by a circadian system.
Abstract
No abstract has been registered
Abstract
To increase the annual uptake of CO2 as well as the long-term storage of carbon (C) in forests, the Norwegian government consider large-scale replacements of native, deciduous forests with faster-growing species like Norway spruce. To assess the effects of tree species change on ecosystem C and nitrogen (N) stocks and soil chemistry, we used a paired plot approach including stands of native downy birch and planted 45 – 60-year-old Norway spruce. The birch stands were used as reference for the assessment of differences following the tree species change. We found significantly higher C and N stocks in living tree biomass in the spruce stands, whereas no significant differences were found for dead wood. The cover of understory species groups, and the C and N stocks of the aboveground understory vegetation was significantly higher in the birch stands. The tree species change did not affect the soil organic carbon (SOC) stock down to 1 m soil depth; however, the significantly higher stock in the forest floor of the spruce stands suggested a re-distribution of SOC within the profile. There was a significant positive correlation between the SOC stock down to 30 cm soil depth and the total ecosystem C stock for the birch stands, and a negative correlation for the spruce stands. Significant effects of tree species change were found for C and N concentrations, C/N, exchangeable acidity, base saturation, and exchangeable Ca, K, Mg, Na, S, and Fe in the organic horizon or the upper mineral soil layer. The total ecosystem C stock ranged between 197 and 277 Mg ha-1 for the birch stands, and 297 and 387 Mg ha-1 for the spruce stands. The ecosystem C accumulation varied between 32 and 142 Mg ha-1 over the past 45-60 years, whereas the net ecosystem C capture was considerably lower and potentially negative. Our results suggest that the potential to meet the governments’ targets to increase C sequestration depend on the C debt incurred from the removed birch stands, the rotation length, and potentially also the susceptibility of the different stand types to future risk factors related to climate change.
Authors
Katherine Ann Gredvig NielsenAbstract
No abstract has been registered
Authors
Kristian Muri Knausgård Siv Skar Filippo Sanfilippo Albert Buldenko Henning Lindheim Jakob Lunde Eligijus Sukarevicius Kjell Gunnar RobbersmyrAbstract
Aquaponic systems are engineered ecosystems combining aquaculture and plant production. Nutrient rich water is continuously circulating through the system from aquaculture tanks. A biofilter with nitrifying bacteria breaks down fish metabolism ammonia into nitrite and nitrate, which plants and makes the aquaculture wastewater into valued organic fertiliser for the plants, contenting essential macro and micro elements. At the same time, plants are cleaning the water by absorbing ammonia from the fish tanks before it reaches dangerous levels for the aquatic animals. In principle, the only external input is energy, mainly in the form of light and heat, but fish food is also commonly provided. Growing fish food is potentially feasible in a closed loop system, hence aquaponic systems can possibly be an important source of proteins and other important nutrition when, for example, colonising other planets in the future. Fully autonomous aquaponic systems are currently not available. This work aims at minimising manual labour related to cleaning pipes for water transport. The cleaning process must be friendly to both plants and aquatic animals. Hence, in this work, pure mechanical cleaning is adopted. A novel belt-driven continuum robot capable of travelling through small/medium diameter pipes and manoeuvring branches and bends, is designed and tested. The robot is modular and can be extended with different cleaning modules through an interface providing CAN-bus network and electric power. The flexible continuum modules of the robot are characterised. Experimental results demonstrate that the robot is able to travel through pipes of diameter 50 mm to 75 mm, and also capable of handling T-branches of up to 90 degrees.
Abstract
No abstract has been registered
Abstract
Grass clover crops were harvested with or without application of 4 L/t of a formic- and propionic acid-based silage additive and ensiled in one bunker silo and 6 round bales per treatment in each of three harvests. The study aimed to compare losses, grass silage quality and aerobic stability obtained either with round bales or precision chopped grass ensiled in bunker silos. Round bales were either sealed immediately or after delay until bunker silos were covered. Unpredicted rain showers during the three harvests gave crop DM as low as 194, 186 and 213 g/kg, respectively. Due to the lower pressure exerted on the crop by the baler than by packing vehicles in the bunkers, and the longer particle length in bales, densities in baled silage were much lower than in bunker silage, 531 vs 833 kg/m3 (P < 0.001), and 111 vs 164 kg DM/m3 (P < 0.001). Presumably due to early cell rupture and higher release of effluent caused by the applied acid, densities were higher in treated than in untreated silage, in bunkers 170 vs. 159 kg DM/m3 (P = 0.08), and in bales, 114 vs. 109 kg DM/m3 (P = 0.02). A much lower proportion of ensiled crop DM could be offered to livestock from bunkers than from round bales, 833 vs. 927 g/kg (P < 0.001). The amount of moulded, wasted silage DM was significantly higher in bunkers than in bales, 26 vs. 0.6 g/kg, (P < 0.001), and the sum of DM lost by crop respiration, effluent runoff, anaerobic fermentation, aerobic deterioration and gaseous losses was significantly higher from bunkers than bales, 141 vs. 72 g/kg (P < 0.002). Acid treatment caused only minor decreases in DM losses. It restricted acid fermentation and improved silage intake potential both in bunkers and bales (P < 0.001), and caused higher stability in bales (P < 0.009). High ethanol concentrations were found in acid treated bunker silage but not in treated bale silage. Also, a reduction in heat induced increases in fiber bound protein obtained by acid treatment in bales, but not in bunkers, suggested that the applied dosage was too low to restrict heating in bunkers, and favored yeast growth. The larger surface area susceptible to heating, and loss of ad ditive in effluent, make higher acid dosages, or a higher proportion of ingredients that inhibit yeast growth, necessary to low DM grass crops ensiled in bunkers.
Authors
Ingunn Øvsthus Kristian Thorup-Kristensen Randi Seljåsen Hugh Riley Peter Dörsch Tor Arvid BrelandAbstract
Mechanistic models are useful tools for understanding and taking account of the complex, dynamic processes such as carbon (C) and nitrogen (N) turnover in soil and crop growth. In this study, the EU-Rotate_N model was first calibrated with measured C and N mineralization from nine potential fertilizer resources decomposing at controlled soil temperature and moisture. The materials included seaweeds, wastes from the food industry, food waste anaerobically digested for biogas production, and animal manure. Then the model’s ability to predict soil and crop data in a field trial with broccoli and potato was evaluated. Except for seaweed, up to 68% of added C and 54–86% of added N was mineralized within 60 days under controlled conditions. The organic resources fell into three groups: seaweed, high-N industrial wastes, and materials with high initial content of mineral N. EU-Rotate_N was successfully calibrated for the materials of industrial origin, whereas seaweeds, anaerobically digested food waste and sheep manure were challenging. The model satisfactorily predicted dry matter (DM) and N contents (root mean square; RMSE: 0.11–0.32) of the above-ground part of broccoli fertilized with anaerobically digested food waste, shrimp shell pellets, sheep manure and mineral fertilizers but not algal meal. After adjusting critical %N for optimum growth, potato DM and N contents were also predicted quite well (RMSE: 0.08–0.44). In conclusion, the model can be used as a learning and decision support tool when using organic materials as N fertilizer, preferably in combination with other models and information from the literature.
Abstract
Accurate assessment of crop nitrogen (N) status and understanding the N demand are considered essential in precision N management. Chlorophyll fluorescence is unsusceptible to confounding signals from underlying bare soil and is closely related to plant photosynthetic activity. Therefore, fluorescence sensing is considered a promising technology for monitoring crop N status, even at an early growth stage. The objectives of this study were to evaluate the potential of using Multiplex® 3, a proximal canopy fluorescence sensor, to detect N status variability and to quantitatively estimate N status indicators at four key growth stages of maize. The sensor measurements were performed at different growth stages, and three different regression methods were compared to estimate plant N concentration (PNC), plant N uptake (PNU), and N nutrition index (NNI). The results indicated that the induced differences in maize plant N status were detectable as early as the V6 growth stage. The first method based on simple regression (SR) and the Multiplex sensor indices normalized by growing degree days (GDD) or N sufficiency index (NSI) achieved acceptable estimation accuracy (R2 = 0.73–0.87), showing a good potential of canopy fluorescence sensing for N status estimation. The second method using multiple linear regression (MLR), fluorescence indices and GDDs had the lowest modeling accuracy (R2 = 0.46–0.79). The third tested method used a non-linear regression approach in the form of random forest regression (RFR) based on multiple sensor indices and GDDs. This approach achieved the best estimation accuracy (R2 = 0.84–0.93) and the most accurate diagnostic result.