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.
2004
Authors
Arne O. Stuanes Richard Wright Heleen A. de Wit Lars R. Hole Øyvind Kaste Jan MulderAbstract
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Authors
Torild Wickstrøm Gunnar OgnerAbstract
A humus sample and a mineral soil sample were collected to investigate different sample pretreatments and their effects on the quality (mean value and uncertainty) of soil chemical data. Thirty-four humus subsamples and sixty mineral subsamples were prepared for chemical analysis. Diverse combinations of sieving, milling or grinding were utilized before the determination of Kjeldahl nitrogen (Kj-N), pH, extractable elements, and a few other chemical parameters.The humus subsamples were sieved, sieved and milled or sieved and ground. Relative to sieving, grinding improved the uncertainty in the determination by 210 times [highest for calcium (Ca), manganese (Mn), Kj-N, loss on ignition and volume weight].The mineral soil subsamples were either sieved or sieved and ground. The uncertainty was improved by 24 times for aluminum (Al), barium (Ba), Ca, hydrogen (H), potassium (K), sulphur (S), silicon (Si), zinc (Zn), and nitrogen (N) when grinding was applied.The result increased for almost all of the chemical parameters when the samples (humus and mineral) were ground in addition to sieving. The maximum increase in mean value was observed for Si (330%), iron (Fe) (200%) and carbon (C), K, magnesium (Mg), Mn, sodium (Na) (1734%).The determination of Kj-N was less influenced (016%) by different pretreatments but the uncertainty in the determination was improved up to 10 times when the sample was ground.Different sieving techniques were also utilized. It was shown that different sieving techniques altered the mean value for Ba, Fe, K, Mg, Si, Zn, pH, and loss on ignition, while the uncertainty was unaffected.All subsamples were reanalyzed after 15 months, without mixing in each sample before weighing. An increase in concentration was observed for C, Fe, phosphorus (P), S (up to 130%) and in volume weight (626%) while a decrease was observed for Ca, K, Mg, strontium (Sr), Zn (727%).
Authors
Per Holm Nygaard Heleen A. de WitAbstract
Aluminium (Al), mobilized by acidic deposition, has been claimed to be a major threat to forest vitality. Fine root mortality, decreased root growth and reduced nutrient uptake have been observed in controlled laboratory experiments where roots of tree seedlings were exposed to elevated concentrations of Al. Yet, evidence for Al-induced root damage from forest stands is scarcely reported. Nevertheless, Al dissolved in soil water has received a key role in the critical load concept for forests. Here, we present effects of artificially elevated concentrations of Al in the soil solution on fine roots in a middle-aged stand of Norway spruce (Picea abies (L.) Karst.). Although the inorganic Al concentrations about 200 M and Ca:Al ratio about 0.7 that were established in the soil solution within this experiment have been associated with reduction of root growth and root mortality for spruce seedlings in hydroponic studies, no acute damage on fine roots was observed. Three years of treatment did not cause visual root damage, nor were effects on fine root necromass observed. Fine root necromass made up about 10 % of fine root biomass for all treatments. However, significantly lower molar Ca:Al and Mg:Al ratios in living and dead fine roots were found in the plots where Al concentrations were highest and ratios of Ca to Al in the soil solution were lowest. The lack of response on fine root biomass suggests that forest stands tolerate higher Al levels than results from laboratory experiments indicate. We conclude that effect studies in the laboratory have limited value for field conditions. The key role of Al toxicity, expressed as the Ca/Al ratio, in critical load calculations for forests may have to be reconsidered.
Authors
Nina Elisabeth Nagy Carl Gunnar Fossdal Lars Sandved Dalen Anders Lønneborg Inger Heldal Øystein JohnsenAbstract
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Authors
Sissel Torre Päivi Rinne Carl Gunnar Fossdal Heather Danforth Stein Erik Lid Ragnhild Nestestog Chris Van der SchootAbstract
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Since 1993, Norwegian governmental subsidies have been applied to preserve valuable semi-natural grasslands in Norway. After 8 years of management and payments, the effects of the subsidies were investigated in the county of Nord-Trøndelag. The intention of the subsidies, to secure both open landscapes and biodiversity, was not obtained due to a general lack of knowledge of ecology and biodiversity at all levels. This clearly demonstrates the importance of knowledge and information exchange between scientists, authorities, politicians and farmers to secure maintenance of the most valuable semi-natural grasslands. In addition, transdisciplinary research and exchange of knowledge between archaeologists, historians and ecologists are necessary to preserve the most valuable cultural landscapes with regard to both biodiversity and cultural monuments. This study was presented at the EGF meeting 21-24 June 2004, Luzern, Switzerland.
Authors
Tove M. Østensvik Kaj Bo VeierstedAbstract
No abstract has been registered