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.
2017
Abstract
No abstract has been registered
Authors
Nils-Otto KitterødAbstract
Unconsolidated sediment cover thickness (D) above bedrock was estimated by using a publicly available well database from Norway, GRANADA. General challenges associated with such databases typically involve clustering and bias. However, if information about the horizontal distance to the nearest bedrock outcrop (L) is included, does the spatial estimation of D improve? This idea was tested by comparing two cross-validation results: ordinary kriging (OK) where L was disregarded; and co-kriging (CK) where cross-covariance between D and L was included. The analysis showed only minor differences between OK and CK with respect to differences between estimation and true values. However, the CK results gave in general less estimation variance compared to the OK results. All observations were declustered and transformed to standard normal probability density functions before estimation and back-transformed for the cross-validation analysis. The semivariogram analysis gave correlation lengths for D and L of approx. 10 and 6 km. These correlations reduce the estimation variance in the cross-validation analysis because more than 50 % of the data material had two or more observations within a radius of 5 km. The small-scale variance of D, however, was about 50 % of the total variance, which gave an accuracy of less than 60 % for most of the cross-validation cases. Despite the noisy character of the observations, the analysis demonstrated that L can be used as secondary information to reduce the estimation variance of D.
Abstract
Based on soil temperature, snow depth and the grown cultivar's maximum attainable level of frost tolerance (LT50c), the FROSTOL model simulates development of frost tolerance (LT50) and winter damage, thereby enabling risk calculations for winter wheat survival. To explore the accuracy of this model, four winter wheat cultivars were sown in a field experiment in Uppsala, Sweden in 2013 and 2014. The LT50 was determined by tests of frost tolerance in November, and the cultivars’ LT50c was estimated. Further, recorded winter survival from 20 winter wheat field variety trials in Sweden and Norway was collected from two winter seasons with substantial winter damages. FROSTOL simulations were run for selected cultivars at each location. According to percentage of winter damage, the cultivar survival was classified as “survived,” “intermediate” or “killed.” Mean correspondence between recorded and simulated class of winter survival was 75% and 37% for the locations in Sweden and Norway, respectively. Stress factors that were not accounted for in FROSTOL might explain the poorer accuracy at the Norwegian locations. The accuracy was poorest for cultivars with intermediate LT50c levels. When low temperature was the main cause of damage, as at the Swedish locations, the model accuracy was satisfying.
Authors
Felix Herzog Gisela Lüscher Michaela Arndorfer Marion Bogers Katalin Balázs Robert Gerald Henry Bunce Peter Dennis Eszter Falusi Jürgen K. Friedel Ilse R. Geijzendorffer Tiziano Gomiero Philippe Jeanneret Gerardo Moreno Marie-Louise Oschatz Maurizio Guido Paoletti Jean-Pierre Sarthou Siyka Stoyanova Erich Szerencsits Sebastian Wolfrum Wendy Fjellstad Debra BaileyAbstract
Habitat descriptors are cost effective biodiversity indicators demanded by stakeholders and required for regional and global biodiversity monitoring. We mapped 195 farms of different types in twelve case study regions across Europe and tested 18 habitat descriptors for scientific validity, information content and ease of interpretation. We propose a core set consisting of (i) four descriptors to measure structural composition and configuration of farms (Habitat Richness, Habitat Diversity, Patch Size, and Linear Habitats), (ii) three descriptors addressing specific habitat types (Crop Richness, Shrub Habitats, and Tree Habitats) and (iii) one interpreted descriptor (Semi-Natural Habitats). As a set, the descriptors make it possible to evaluate the habitat status of a farm and to track changes occurring due to modified land use and/or management, including agri-environmental measures. The farm habitat maps can provide ground truth information for regional and global biodiversity monitoring.
Abstract
No abstract has been registered
Abstract
Turfgrass grow-in on sand-based putting greens usually incurs a high risk for nitrogen (N) leakage. Our objective was to evaluate how substitution of a standard mineral fertilizer with an amino-acid-based fertilizer affects creeping bentgrass (Agrostis stolonifera L.) establishment rate and the concentration of nitrate and total N in drainage water. The experiment was conducted from 19 May to 26 July 2016 in the United States Golf Association green field lysimeter facility at Landvik, Norway. The liquid fertilizers arGrow Turf (70% of N as arginine and 30% as lysine) and Wallco (60% of N as nitrate and 40% as ammonium) were applied at ∼2-wk intervals at the two rates of 1.5 or 3.0 g N m−2 application−1. Results showed significantly faster grow-in on plots receiving amino-acid-based fertilizer than on plots receiving mineral fertilizers; the average turfgrass coverage 26 d after the first fertilization was 75 and 36%, respectively. In parallel with this, the average concentration of nitrate and total N in drainage water, as well as the total N loss, were all reduced by 40 to 45%. Arginine and lysine at 1.5 g N m−2 gave faster grow-in than Wallco at 3.0 g N m−2 and was the only treatment in which the drainage water complied with EU’s requirements for maximum concentration of nitrate in drinking water.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Hadush Tsehaye Beyene May Bente Brurberg Leif Sundheim Arne Tronsmo Dereje Assefa Anne Marte TronsmoAbstract
No abstract has been registered
Authors
Maochuan Hu Takahiro Sayama Xingqi Zhang Kenji Tanaka Kaoru Takara Hong YangAbstract
Low impact development (LID) has attracted growing attention as an important approach for urban flood mitigation. Most studies evaluating LID performance for mitigating floods focus on the changes of peak flow and runoff volume. This paper assessed the performance of LID practices for mitigating flood inundation hazards as retrofitting technologies in an urbanized watershed in Nanjing, China. The findings indicate that LID practices are effective for flood inundation mitigation at the watershed scale, and especially for reducing inundated areas with a high flood hazard risk. Various scenarios of LID implementation levels can reduce total inundated areas by 2%–17% and areas with a high flood hazard level by 6%–80%. Permeable pavement shows better performance than rainwater harvesting against mitigating urban waterlogging. The most efficient scenario is combined rainwater harvesting on rooftops with a cistern capacity of 78.5 mm and permeable pavement installed on 75% of non-busy roads and other impervious surfaces. Inundation modeling is an effective approach to obtaining the information necessary to guide decision-making for designing LID practices at watershed scales.