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.
2017
Sammendrag
Shallow (<1 m deep) snowpacks on agricultural areas are an important hydrological component in many countries, which determines how much meltwater is potentially available for overland flow, causing soil erosion and flooding at the end of winter. Therefore, it is important to understand the development of shallow snowpacks in a spatially distributed manner. This study combined field observations with spatially distributed snow modelling using the UEBGrid model, for three consecutive winters (2013–2015) in southern Norway. Model performance was evaluated by comparing the spatially distributed snow water equivalent (SWE) measurements over time with the simulated SWE. UEBGrid replicated SWE development at catchment scale with satisfactory accuracy for the three winters. The different calibration approaches which were necessary for winters 2013 and 2015 showed the delicacy of modelling the change in shallow snowpacks. Especially the refreezing of meltwater and prohibited runoff and infiltration of meltwater by frozen soils and ice layers can make simulations of shallow snowpacks challenging.
Sammendrag
Land management and spatial planning are closely linked to the adaptation of water management to climate change impacts. Land management has an influence on the ability of the soil to retain precipitation or flood water and sustainable land use can help to better manage risks related to both increased precipitation/flooding and water scarcity. Land and soil management can also realize significant synergies between climate change adaptation and mitigation. Agriculture as a key form of land use will play a crucial role in adaptive spatial planning approaches. Intensive agriculture in flood-prone areas is at risk of substantial economic loss in the case of flooding. On the other hand, the increased challenges for flood risk management will create a demand for new ways of accommodating flood water and managing flows, which may increase economic opportunities for water farming. There are sufficient reasons to understand land drainage arrangements importance. Drainage has been identified as the forgotten factor in sustaining a sustainable irrigated agriculture. Surface and subsurface drainage provides a lot of functions that meet some actual and challenging needs. Some of these functions are: resource base protection for food production; sustaining and increasing the yields and rural incomes; irrigation investment protection etc. This paper is based on an analysis of managing water excess in north-western Romania using Romanian expertise in this field but also the results from some bilateral projects between Romania, Norway and Iceland.
Sammendrag
In the Nordic countries, changes in pore structure during winter can affect e.g. water transport capacity in soils after winter. A reduction in pore space can cause an increase in runoff volume due to snowmelt and rain, resulting in flooding and soil erosion. This study quantified the effect of freezing-thawing cycles (FTCs) on the macropore structure of a silt and a sandy soil. Six consecutive FTCs were applied to intact soil samples, which were scanned after 0, 1, 2, 4 and 6 FTCs with an industrial X-ray scanner. Using state-of-the-art image processing and analysis techniques, changes in soil macropore network characteristics were quantified. The results showed that freezing-thawing affected the looser sandy soil more than the silt with its more cohesive structure. However, in both soils freezing-thawing had a negative effect on properties of macropore networks (e.g. reduction in macroporosity, thickness and specific surface area of macropores). These findings can help improve understanding of how undisturbed soils react to different winter conditions, which can be beneficial in the development of models for predicting flooding and soil erosion.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Arctic charr and European whitefish are considered to be strong competitors in lakes, with the latter usually being the superior species. However, high niche plasticity and lake morphometry may suggestively facilitate resource partitioning and coexistence between charr and whitefish. Here, we explore the trophic niche utilization (diet and habitat use) of charr and whitefish co-occurring with brown trout in the deep and oligotrophic Lake Fyresvatnet, southern Norway (59°05’N, 8°10’E). Using CPUE, stomach contents and stable isotope analyses, a distinct resource partitioning was revealed between brown trout and the other two species. Brown trout typically occupied the littoral zone, feeding on benthic invertebrates, surface insects and small-sized whitefish. In contrast, charr and whitefish were predominantly zooplanktivorous, but diverged somewhat in habitat utilization as charr shifted seasonally between the profundal and the littoral zone, whereas whitefish were found in the upper water layers (littoral and pelagic habitats). Accordingly, the stable isotope values of carbon (δ13C) reflected a pelagic orientated prey resource use for both charr and whitefish, whereas brown trout had elevated carbon and nitrogen (δ15N) signatures that reflected their benthivore and piscivore diet, respectively. The findings suggest that charr may not rely upon the profundal zone as a feeding habitat but as a refuge area, and may coexist with whitefish if a third competitive and predatory species like brown trout co-occur in the lake. The study indicates that a general high habitat plasticity of Arctic charr may be essential in the presently observed coexistence with a competitively superior fish species like whitefish, and that a third fish species like brown trout may facilitate this particular fish community structure.
Forfattere
Csilla FarkasSammendrag
Det er ikke registrert sammendrag
Forfattere
Márton Dencső Eszter Tóth Györgyi Y. Gelybó Ilona Kása Ágota Horel Márk Rékási Tünde Takács Csilla Farkas Imre Potyó Nikolett UzingerSammendrag
A talajok tulajdonságainak javítása céljából végzett bioszénnel történő kezelések hatása a különböző fizikai, kémiai és biológiai tulajdonságú talajok esetében még nem teljesen ismert. Kísérleteinket homoktalajon végeztük az MTA ATK TAKI Őrbottyánban lévő kísérleti telepén, ahol kukoricát vetettek. Hét kezelést vizsgáltunk, négy ismétlésben. Három esetben a talaj különböző dózisban bioszenet és konstans dózisú műtrágyát tartalmazott (0,1 m/m%; 0,5 m/m%; 1 m/m%; jelölésük BC0,1M; BC0,5M; BC1,0M), három esetben pedig a fent említett bioszén dózisokat egységesen 10 t/ha komposzttal egészítettük ki (BC0,1K; BC0,5K; BC1,0K). Ezek mellett pedig kialakítottunk egy bioszén és komposzt mentes abszolút kontroll (K) kezelést is. Kutatásunk során talajszondákkal monitoroztuk a talajnedvességtartalmának alakulását, valamint statikus kamrás mintavételi eljárással a talajlégzést is mértük a kezelésekben. A talajnedvesség éves átlagát nézve 1% bioszénnel és komposzttal kezelt parcella esetében a talaj nedvességtartalma nem szignifikáns mértékben növekedett a bioszén és komposzt mentes abszolút kontroll környezethez képest. Csapadékesemények alkalmával az 1% bioszenet és komposztot tartalmazó parcellában nőtt meg legjobban a talajnedvesség, illetve hasonlóan alakult a nedvességtartalom a 0,5% bioszénnel kezelt műtrágyás parcellában is. Csapadékesemények után az összes bioszenet és műtrágyát, illetve bioszenet és komposztot tartalmazó parcellában gyorsabban száradt ki a talaj a kontrollhoz képest. A csapadékban szegényebb, szárazabb időszak alkalmával egyedül az 1% bioszenet és komposztot tartalmazó kezelés talajnedvessége volt magasabb a kontrollhoz képest, a 0,5% bioszénnel és műtrágyával kezelt, komposzt mentes esetben a nedvesség hasonlóan alakult a kontrollhoz viszonyítva, az összes többi esetben jóval az alatt maradtak az értékek. Összességében megállapítható, hogy a komposztot tartalmazó talajok érzékenyebben reagáltak a csapadékra, a legjobb vízgazdálkodást az 1% bioszén és komposzt kezelés esetében értük el. Önmagában a bioszén nagy mennyiségű (1,0 m/m%) adagolása nem volt egyértelműen talajnedvesség-növelő hatású. A bioszén szén-dioxid forgalomra történő hatását a talajlégzés mérésével vizsgáltuk. A bioszénnel, valamint műtrágyával kezelt és a kontroll kezelések között csak néhány esetben volt különbség. A komposzttal kevert bioszén kezelések alkalmával hasonló eredményre jutottunk, mint a műtrágyával kevert bioszén esetében. Eredményeink alapján arra következtethetünk, hogy a talajlégzés nem függött a bioszén dózisától. A bioszén talajlégzésre gyakorolt hatása közvetett módon, a talajnedvesség befolyásolásán keresztül valósul meg, mivel bioszenet alkalmazva bizonyos esetekben a talajnedvesség emelkedett a kontrollhoz képest, ekkor a talajlégzés ugyancsak magasabb lett, amely jelenség a komposzttal kezelt esetekben jól megfigyelhető volt.
Forfattere
Hans Thodsen Csilla Farkas Jaroslaw Chormanski Dennis Trolle Gitte Blicher-Mathiesen Ruth Grant Alexander Melvold Engebretsen Ignacy Kardel Hans Estrup AndersenSammendrag
The main environmental stressor of the Baltic Sea is elevated riverine nutrient loads, mainly originating from diffuse agricultural sources. Agricultural practices, intensities, and nutrient losses vary across the Baltic Sea drainage basin (1.75 × 106 km2 , 14 countries and 85 million inhabitants). Six “Soil and Water Assessment Tool” (SWAT) models were set up for catchments representing the major agricultural systems, and covering the different climate gradients in the Baltic Sea drainage basin. Four fertilizer application scenarios were run for each catchment to evaluate the sensitivity of changed fertilizer applications. Increasing sensitivity was found for catchments with an increasing proportion of agricultural land use and increased amounts of applied fertilizers. A change in chemical fertilizer use of ±20% was found to affect watershed NO3-N loads between zero effect and ±13%, while a change in manure application of ±20% affected watershed NO3-N loads between zero effect and −6% to +7%.
Sammendrag
Several mathematical models have been proposed for describing particle‐size distribution (PSD) data, but their characteristics and accuracy have not been investigated for the < 0.002, 0.002–0.05 and 0.05–2.0‐mm fractions separately. Therefore, the primary objective of this study was to examine the characteristics of various PSD models and to evaluate the accuracy of fitting to the entire PSD curve and to each of the three fractions separately. Thirty‐six PSD models were fitted to the experimental data of 160 soil samples from Iran. The beerkan estimation of soil transfer (BEST), Fredlund unimodal and bimodal, two‐ and three‐parameter Weibull, Rosin–Rammler and van Genuchten models provided the best fit to the experimental data of the three size fractions above, but with a different order of performance for the different fractions. For all textural fractions, the following models performed substantially less well than the other models: the offset‐non‐renormalized lognormal, simple lognormal, S‐curve, Schuhmann, Yang, Turcotte and Gompertz models. A comparison of the overall accuracy and simplicity of the models indicated that the BEST, two‐ and three‐parameter Weibull and Rosin–Rammler models provided the best fit to the experimental data for the entire curve, which is similar but does not correspond fully to the findings of a similar, earlier study. We found that the number of model parameters and the type of equation did not explain the models' fitting capabilities. We also found that the iterated function system (IFS) model performed better than the PSD models for all fractions. Comprehensive comparisons of PSD models will be of value to future model users, but it is important to note that such comparisons will remain dataset dependent. This is likely to continue until they are tested on a near‐infinite synthetic dataset that covers all possible data options.
Forfattere
Kris Van Looy Johan Bouma Michael Herbst John Koestel Budiman Minasny Umakant Mishra Carsten Montzka Attila Nemes Yakov A. Pachepsky José Padarian Marcel G. Schaap Brigitta Tóth Anne Verhoef Jan Vanderborght Martine J. van der Ploeg Lutz Weihermüller Steffen Zacharias Yonggen Zhang Harry VereeckenSammendrag
Soil, through its various functions, plays a vital role in the Earth’s ecosystems and provides multiple ecosystem services to humanity. Pedotransfer functions (PTFs) are simple to complex knowledge rules that relate available soil information to soil properties and variables that are needed to parameterize soil processes. In this paper, we review the existing PTFs and document the new generation of PTFs developed in the different disciplines of Earth system science. To meet the methodological challenges for a successful application in Earth system modeling, we emphasize that PTF development has to go hand in hand with suitable extrapolation and upscaling techniques such that the PTFs correctly represent the spatial heterogeneity of soils. PTFs should encompass the variability of the estimated soil property or process, in such a way that the estimation of parameters allows for validation and can also confidently provide for extrapolation and upscaling purposes capturing the spatial variation in soils. Most actively pursued recent developments are related to parameterizations of solute transport, heat exchange, soil respiration, and organic carbon content, root density, and vegetation water uptake. Further challenges are to be addressed in parameterization of soil erosivity and land use change impacts at multiple scales. We argue that a comprehensive set of PTFs can be applied throughout a wide range of disciplines of Earth system science, with emphasis on land surface models. Novel sensing techniques provide a true breakthrough for this, yet further improvements are necessary for methods to deal with uncertainty and to validate applications at global scale.