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.
2002
Forfattere
Brit Salbu Marit N. Pettersen Gunnhild Riise Tore Krogstad Ole Martin Eklo Olav LodeSammendrag
Information on the mobility of pesticides in soil-water systems is essential for assessing the environmental impact for receiving waters such as surface runoff and transport to rivers and lakes or infiltration to ground water supplies. The present work demonstrates that the herbicide Bentazon, being a weak acid, was water soluble and mobile in soil-organic material systems. The sorption was relatively high at low pH and decreased for pH higher than 4. The sorption was influenced by the addition of organic material, especially composts having high TOC (compost from domestic animal). Low Kd/TOC and low Kd/CEC ratios for soil-compost mixtures indicated that TOC and the cation exchange capacities of the organic material were important for retention of Bentazon in organic soils. Sequential extractions demonstrated also that all Bentazon could be reversibly extracted with electrolytes having sufficient ionic strength. Thus, the mobile fraction of Bentazon depends on the ionic strength in the soil solution, reflecting that ion exchange mechanisms are of major importance. The sorption of the non-polar insecticide Alpha-cypermethrin was high to all soil-compost systems investigated. The distribution coefficient Kd and the low Kd/TOC and Kd/CEC ratios demonstrated that organic material being rich in TOC and to a certain extent in CEC played an important role for sorption of Alpha-cypermethrin. Thus, the retention of "-Cypermethrin in soils could be attributed to association to TOC in soils, depending on the nature and concentration of the organic material. As the fraction of Alpha-cypermethrin extracted by rainwater was surprisingly high (40-60 %), the mobility was attributed to the association of low molecular mass organic material or organic colloids from the composts present in the soil solutions. The present work demonstrates that Bentazon should be mobile, while Alpha-cypermethrin should be retained in soil-organic material systems under soil solution pH conditions. Following heavy rain, Bentazon should follow the water transport, as runoff or ground infiltration and the mobile fraction should increase with increasing ionic strength of the soil solutions. The mobility of Alpha-cypermethrin should be low, but could increase significantly if associated to mobile low molecular mass organic compounds present in soil solutions.
Forfattere
Ole Martin Eklo Enrique Barriuso Sabine HouotSammendrag
Compost mixed into soil affects strongly the mobility of atrazine. The main peak of atrazine in the leachate from soil columns with compost was retarded more than 20 days compared with untreated soil. Addition of DOM-solution generated from the compost increased to some extent the mobility of atrazine. However, the DOM-solution destroyed the structure of the soil, and the soil columns were clogging after 23 days. Soil microorganisms seemed to be able to degrade part of the atrazine and organic matter in the soil columns. The effect of the organic matter on sorption and thereby reducing the mobility of atrazine was confirmed by batch experiments. De-ethyl atrazine was the most mobile degradation product and the amount of hydroxy-atrazine increased during the experiment. Addition of compost to the soil may be a method to reduce leaching to groundwater, but as addition of organic matter reduce the degradation rate, it is not evident what the total effect on risk reduction for leaching in the long term will be.
Forfattere
Bernt-Håvard Øyen Kjell AndreassenSammendrag
Det er ikke registrert sammendrag
Forfattere
Bernt-Håvard Øyen Kjell AndreassenSammendrag
Det er ikke registrert sammendrag
Forfattere
Mats Høglind Helge BonesmoSammendrag
The nutritive value of timothy, the most widely grown sown grass species for silage and hay production in Scandinavia, varies considerably among years due to varying environmental conditions. This makes it difficult to predict the economically optimum harvest time, which represents a compromise between herbage quantity and quality: the DM yield increases with advanced stage of sward development whereas the nutritive value decreases. The aim of this work was to investigate the possibilities to develop a mechanistic model to predict rates of change in digestibility and fibre content in Norwegian timothy. Here, we present the basic features of the model and make a first evaluation against field data.
Sammendrag
Modellutprøving ble foretatt på grunnlag av data fra 10 norske gjødslingsfeltforsøk med sommerkål, vinterkål og kepaløk dyrket på ulike jordarter i distrikt med ulik nedbør. Tilvekstkurver og N-opptaksmønsteret gjennom sesongen ble bestemt i alle forsøkene. På dette grunnlaget ble modellens funksjoner for vekst og N-gjenvinning forbedret.
Forfattere
G. van TolSammendrag
Det er ikke registrert sammendrag
Sammendrag
The flow and transport of a non-reactive tracer and melt water was monitored in a heterogeneous coarse sandy unsaturated zone in southeastern Norway, during the snowmelt of 2001. Electrical resistivity tomography (ERT) as well as conventional suction cup techniques was employed. A frozen solution of NaBr in water was supplied as a line source on the ground surface above two parallel vertical profiles monitored by the two measurement systems prior to the onset of snowmelt. The two monitored vertical profiles were separated by approximately 1 m. The results were analysed by visual comparison of images and by the use of spatial moments analysis. The two measurement approaches showed that the system was affected by the presence of preferential flow paths during the early stages of the snowmelt, perhaps due to ice near the surface, but the major part of the plume moves uniformly later in the snow-melting period. After most of the tracer plume has reached the depth monitored by both systems (i.e. below 0.4 m depth) there is a good consistency between the two datasets. Spatial moment calculations on the basis of ERT cannot be used to describe the movement of tracer alone, as the resistivity is affected by changes in both saturation levels and tracer concentration. Nevertheless, ERT appears to be an appropriate method to characterise regions of localised high infiltration in this type of soil. The method therefore constitutes a possible alternative and supplement to suction cups in a monitoring system.
Sammendrag
The susceptibility of Delia floralis eggs, neonates and larvae and the susceptibility of Galleria mellonella and Mamestra brassicae larvae to seven different Norwegian isolates of the insect pathogenic, hyphomycetous fungi Tolypocladium cylindrosporum, Metarhizium anisopliae and Beauveria bassiana, were investigated. Metarhizium anisopliae isolate ARSEF 5520 was highly virulent to G. mellonella larvae and caused 100% mortality when tested at a concentration of 3.6x106 conidia/ml. The same M. anisopliae isolate was not virulent to D. floralis larvae. Isolates of T. cylindrosporum, were equally virulent to G. mellonella and D. floralis causing up to 36.0% mortality of larvae. It is suspected, however, that the use of grated rutabaga as a food source in the D. floralis bioassay reduced the fungal virulence of both M. anisopliae and T. cylindrosporum to D. floralis. Among three T. cylindrosporum isolates tested at a concentration of 1.0x107 against eggs of D. floralis none of them reduced the hatching percentage. One isolate, ARSEF 5525 did, however, significantly reduce the longevity of neonates. Beauveria bassiana isolates ARSEF 5510 and ARSEF 5370 tested at a concentration of 1.0x107resulted in M. brassicae mortality levels of 70.0 and 55.0% respectively. The B. bassiana isolate ARSEF 5557, however, was not virulent to M. brassicae. Among the three isolates tested against M. brassicae the two virulent isolates produced a red pigment, probably oosporein, when cultured in Sabouraud dextrose agar.
Sammendrag
Det er ikke registrert sammendrag