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.
2001
Abstract
Materials and Methods: In the field, fresh samples were obtained from different sources. Lake samples were collected from Lake Årungen, which is located in Ås. Stream samples were collected from Ås and Birkenes in southern Norway. All the samples were filtered in the field through 0.45 um membrane filters using syringes. Then the samples were fractionated through Bond Elut SCX cartridges connected to a portable vacuum pump, based on the method of Wickstrøm et al. (2000). A portion of the sample was passed immediately through the cation exchange cartridge. After the fieldwork another portion of the sample was taken to the laboratory where the same fractionation procedure was applied. These two fractions were then analysed for non-labile aluminium. A portion of the unfractionated sample was also analysed for total dissolved aluminium. An additional laboratory fractionation with a time lag was also applied to observe storage effects. Subsequent determination of total elements was done using ICP-AES. Transport, pretreatment and storage can also have an effect on the pH and organic matter concentration of the samples and, through this, on the equilibrium between different Al fractions. To evaluate pH differences prior to analysis, pH values were also measured in the field and in the laboratory. DOC was also determined. Differences between fractionation in the field and fractionation in the laboratory: In this study, non-labile fractions of Al were compared instead of the labile fractions of Al (which can be removed from solution on passage through cation exchange column) that are believed to have the greatest toxic effect on organisms.
– Fertilization experiments on forest mineral soils: A review of the Norwegian results
Petter Nilsen
Authors
Petter NilsenAbstract
The paper gives a brief overview of the background, history and main results of forest fertilization experiments on mineral soils in Norway. Positive results of initial phosphorus (P) fertilization on survival and growth of Norway and Sitka spruce have only been achieved in the coastal districts of western Norway. Other elements have seldom given any significant effect.In young and old stands of Norway spruce and Scots pine nitrogen (N) fertilization with 150 kg N ha-1 usually gave increment increases in the range of 1-2 m3 ha-1 yr-1, for a period of 6-8 yrs after application. Given individually, no other element has proved stimulating to stem growth in a similar way. In young Norway spruce stands P has often given additional growth response when given together with N. Liming has been shown to have no or negative effects on tree growth. Fertilization experiments have changed from being management orientated towards addressing the problems of possible nutrient imbalances.
Authors
Halvor TorgersenAbstract
No abstract has been registered
Authors
Oddvar SkreAbstract
Småplanter av tre bjørkepopulasjonar (Betula pubescens) blei dyrka i veksttorv ved to ulike gjødselnivå, tilsvarande 1 og 10 g N m-2 yr-1 ved 50 og 450 m høgd i det sørlege Noreg. Det var ei sterk opphoping av karbohydrat i røter frå det høgaste feltet, samanlikna med det lågaste. Normal og alternativ (cyanid-resistent) respirasjon blei målt i stengel- og rotsegment og på avskorne bladskiver frå dei tre bjørkepopulasjonane. Den totale og alternative mørkerespirasjonen minka med aukande temperatur i bladskiver og stengelsegment. I rotsegment frå dei same plantene auka derimot totalrespirasjonen med temperaturen. Ved lågt gjødselnivå var det ein viss reduksjon av respirasjonen i skot ved høg temperatur, og det meste av denne var cyanid-resistent, i.e. ikkje kopla til veksten. Den økologiske tydinga av dette er at ved låg temperatur kan auka alternativ respirasjon i blad og stengel føra til redusert vekst. Ved høg temperatur derimot, tyder auka totalrespirasjon i røter på auka absorbsjon av nitrogen i røter, som igjen fører til auka fotosyntesekapasitet, som kan kompensera for karbohydratmangel ved sterk vekst. Den alternative respirasjonen ved lågt næringsnivå og temperatur kan vera ein mekanisme for å unngå vekst ved ugunstige forhold.
Abstract
No abstract has been registered
Authors
Peder GjerdrumAbstract
Fuktforandringer i trelasten etter tørking før den når frem til sin endelige bruk er studert. En dynamisk modell for fuktutvikling i stabilt klima er utviklet og analysert. Temperaturområdet er 3 - 60 gr C, og modellen gjelder for planker av 50 mm gran. Arbeidet inngår i bestrebelene for å finne frem til en mer generell modell for et reelt, vekslende klima.
Authors
E. Mäenpää Oddvar Skre E. Malila R. Partanen Frans-Emil Wielgolaski Kari M. LaineAbstract
Gjennom tre sesongar (1983-85) blei det hausta prøver av bjørk (Betula pubescens) og ulike planteslag i feltskiktet på på seks lokalitetar i bjørkeskog langs ein kyst-innlandsgradient i bjørkeskog i Nord-Skandinavia. Prøvene blei skilt i grupper etter vevstype og analysert for stivelse og løyselege sukker. Analysene viste ein kraftig nedgang i karbohydratinnhaldet gjennom vekstfasen om våren, etterfølgt av ei gradvis oppbygging frå fotosyntesen i nye blad. Deretter var det ein gradvis nedgang, først på grunn av frukt- og frøutvikling, deretter sekundærvekst, og endeleg respirasjonstap gjennom mørkeperioden om vinteren. Denne nedgangen var størt på lågtliggande lokalitetar med lite nedbør.
Authors
H. Saxe M.G.R. Cannell Øystein Johnsen M.G. Ryan G. VourlitisAbstract
No abstract has been registered
Authors
Sondre Skatter R.R. ArcherAbstract
No abstract has been registered
Abstract
Understanding sulfate transport and retention dynamics in forest soils is a prerequisite in predicting SO4 concentration in the soil solution and in lake and stream waters. In this study forest soil samples from the Grdsjn catchment, Sweden, were used to study SO4 transport in soil columns from the upper three soil horizons (E, Bs and BC).The columns were leached using a sequential leaching technique. The input solutions were CaSO4 equilibrated with forest floor material. Leaching behavior of SO4 and concentration in the effluent were measured from columns from individual horizons.SO4 was always retained in the Bs and BC horizons, while the pattern for the E horizon varied. Attempts were also made to model SO4 breakthrough results based on miscible displacement approaches and solute convection-dispersion equation (CDE) in porous media. Several retention mechanisms were incorporated into the CDE in order to account for possible reversible and irreversible SO4 reactions in individual soil layers.The model was not successful in describing the mobility of SO4 in the top (E) horizon. Moreover, a linear equilibrium approach was generally inadequate for describing sulfate mobility in the Bs and BC horizons whereas improved model descriptions were obtained when non-linear equilibrium and kinetic approaches were utilized.We conclude that sulfate retention during transport in this forest soil is most likely controlled by kinetic reactivity of SO4 by reversible and irreversible mechanisms.