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
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Mehreteab TesfaiSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
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
Rapporten presenterer en laboratoriemetode for bestemmelse av effekter på frysing og tining på aggregatstabilitet. Steg for steg prosedyrer for de ulike delene av behandlingen er beskrevet i detalj. Behandlingen omfatter uttak av jord, sikting av jord til ønsket aggregatstørrelse, pakking av jord i sylindre, innstilling av vanninnhold i prøvene, fryse-tine behandling under kontrollerte forhold, og stabilitetstester med regnsimulator og våtsikteapparat.
Sammendrag
Det er ikke registrert sammendrag
Del av bok/rapport – Agro-hydrological study of Sub-Basin III, Managua, Nicaragua.
Johannes Deelstra
Forfattere
Johannes DeelstraSammendrag
Summary: The report describes the erosion problems in Sub-Basin III, Managua, Nicaragua and proposes measures to alleviate these. Soil loss in the upper part of the catchment causes serious sedimentation in the downstream reaches of the open water courses, resulting in a reduced discharge capacity for water. This in its turn leads to flooding of urban areas during high rainfall periods and under extreme events can lead to closure of the international airport. In addition does the soil loss from agricultural land contribute in the ongoing deterioration of the water quality of Lake Managua while at the same time leading to a decrease in soil fertility and production capacity. An assessment is made of the present soil loss from agricultural land in the Subcuenca III and recommendations are proposed concerning soil conservation measures. Soil loss has been calculated using the Universal Soil Loss Equation (USLE). Very high figures for soil loss were obtained and the question has been raised whether these were realistic. However, the calculations were seriously hampered due to the lack of input data while at the same time were no data were available for validation.. Therefore, also proposals are given for a measurement programme to improve data availability and to be able to verify calculated soil loss. The report is the original to the report " Estudio Agrohidrológico" which is part of the "Estudio Agroecologico y de Drenaje Pluvial de la Subcuenca III de la Cuenca Sur del Lago de Managua" (Agro-Ecological and Rainwater Drainage Study of Sub-Basin III of the Southern Basin of Lake Managua).
Forfattere
Johannes DeelstraSammendrag
Summary: The report describes the erosion problems in Subcuenca III, Managua, Nicaragua and proposes measures to alleviate these. Soil loss in the upper part of the catchment causes serious sedimentation in the downstream reaches of the open water courses, resulting in a reduced discharge capacity for water. This in its turn leads to flooding of urban areas during high rainfall periods and under extreme events can lead to closure of the international airport. In addition does the soil loss from agricultural land contribute in the ongoing deterioration of the water quality of Lake Managua while at the same time leading to a decrease in soil fertility and production capacity. An assessment is made of the present soil loss from agricultural land in the Subcuenca III and recommendations are proposed concerning soil conservation measures. Soil loss has been calculated using the Universal Soil Loss Equation (USLE). Very high figures for soil loss were obtained and the question has been raised whether these were realistic. However, the calculations were seriously hampered due to the lack of input data while at the same time were no data were available for validation.. Therefore, also proposals are given for a measurement programme to improve data availability and to be able to verify calculated soil loss. The report is translated from the original "Agro-hydrological study of Subcuenca III, Managua, Nicaragua." which is part of the "Estudio Agroecologico y de Drenaje Pluvial de la Subcuenca III de la Cuenca Sur del Lago de Managua