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.
2018
Forfattere
Lillian ØygardenSammendrag
Det er ikke registrert sammendrag
Forfattere
Lillian ØygardenSammendrag
Det er ikke registrert sammendrag
Forfattere
Lillian ØygardenSammendrag
Det er ikke registrert sammendrag
Forfattere
Hermine Mitter Martin Schönhart Franz Sinabell Anja Techen Katharina Helming Benjamin Leon Bodirsky Ian Holman Kasper Kok Heikki Lehtonen Adrian Leip Hermann Lotze- Kampen Erik Mathijs Bano Mehdi Melania Michetti Klaus Mittenzwei Lillian Øygarden Jörg A. Priess Pytrik Reidsma Rudiger Schaldach Erwin Schmid Heidi A. WebberSammendrag
Det er ikke registrert sammendrag
Sammendrag
Degradation of organic chemicals in natural soils depends on oxidation-reduction conditions. To protect our groundwater resources we need to understand the degradation processes under anaerobic conditions. Available iron and manganese oxides are used as electron acceptors for anaerobic degradation and are reduced to the dissolved form of metallic cations in pore water. To monitor this process is a challenge, because anaerobic conditions are difficult to sample directly without introducing oxygen. A few studies have shown an impact of iron reduction on spectral induced polarisation (SIP) signature, often associated with bacterial growth. Our objective is to study the impact of iron and manganese oxide dissolution, caused by degradation of an organic compound, with spectral induced polarisation signatures. Twenty-six vertical columns (30 cm high, inner diameter 4.6 cm) were filled with a sand rich in oxides (manganese and iron) with a static water table in the middle. In half of the columns, a 2 cm high contaminated layer was installed just above the water table. As the contaminant degrades, the initial oxygen is consumed and anaerobic conditions form Every three days over a period of one month, spectral induced polarisation (twenty frequencies between 5mHz and 10 kHz) data were collected on six columns: three contaminated replicates and three control replicates. Chemical analysis was done on twenty columns assigned for destructive water sampling, ten contaminated columns and ten control. The results show an increase of the real conductivity associated with the degradation processes, independent of frequency. Compared with the pore water electrical conductivity in the saturated zone, the real conductivity measurement revealed the formation of surface conductivity before iron was released in the pore water. In parallel, we also observed an evolution of the imaginary conductivity in both saturated and unsaturated zones at frequencies below 1 Hz. Overall, the anaerobic reduction of iron and manganese oxide during the organic degradation increased both the conductive and polarisation component of the complex conductivity.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Jian Liu Peter J. A. Kleinman Helena Aronsson Don Flaten Richard W. McDowell Marianne Bechmann Douglas B. Beegle Timothy P. Robinson Ray B. Bryant Hongbin Liu Andrew N. Sharpley Tamie L. VeithSammendrag
Winter manure application elevates nutrient losses and impairment of water quality as compared to manure applications in other seasons. In conjunction with reviewing global distribution of animal densities, we reviewed worldwide mandatory regulations and voluntary guidelines on efforts to reduce off-site nutrient losses associated with winter manure applications. Most of the developed countries implement regulations or guidelines to restrict winter manure application, which range from a regulative ban to guidelines based upon weather and field management conditions. In contrast, developing countries lack such official directives, despite an increasing animal production industry and concern over water quality. An analysis of five case studies reveals that directives are derived from a common rationale to reduce off-site manure nutrient losses, but they are also affected by local socioeconomic and biophysical considerations. Successful programs combine site-specific management strategies along with expansion of manure storage to offer farmers greater flexibility in winter manure management.
Forfattere
Rachel Cassidy Philip Jordan Marianne Bechmann Brian Kronvang Katarina Kyllmar Mairead ShoreSammendrag
Achieving an operational compromise between spatial coverage and temporal resolution in national scale river water quality monitoring is a major challenge for regulatory authorities, particularly where chemical concentrations are hydrologically dependent. The efficacy of flow-weighted composite sampling (FWCS) approaches for total phosphorus (TP) sampling (n = 26–52 analysed samples per year), previously applied in monitoring programmes in Norway, Sweden and Denmark, and which account for low to high flow discharges, was assessed by repeated simulated sampling on high resolution TP data. These data were collected in three research catchments in Ireland over the period 2010–13 covering a base-flow index range of 0.38 to 0.69. Comparisons of load estimates were also made with discrete (set time interval) daily and sub-daily sampling approaches (n = 365 to >1200 analysed samples per year). For all years and all sites a proxy of the Norwegian sampling approach, which is based on re-forecasting discharge for each 2-week deployment, proved most stable (median TP load estimates of 87–98%). Danish and Swedish approaches, using long-term flow records to set a flow constant, were only slightly less effective (median load estimates of 64–102% and 80–96%, respectively). Though TP load estimates over repeated iterations were more accurate using the discrete approaches, particularly the 24/7 approach (one sample every 7 h in a 24 bottle sampler - median % load estimates of 93–100%), composite load estimates were more stable, due to the integration of multiple small samples (n = 100–588) over a deployment.
Forfattere
Marianne BechmannSammendrag
Dyrket mark i Naurstadfeltet er dominert av langvarig eng og beite. Storfé, hest og mjølkeku var de viktigste husdyrslagene i 2016. Det har vært en nedadgående trend i tilført fosfor og nitrogen gjennom hele overvåkingsperioden, og særlig har den tilførte andelen med mineralgjødsel gått ned. I 2016 ble det også tilført lite husdyrgjødsel. Totalt ble det tilført 1,3 kg fosfor og 7,1 kg nitrogen per dekar i 2016. Næringsstofftapene fra jordbruksarealet utgjorde 270 g P/daa og 2 kg N/daa i 2016/2017, og partikkeltapet 87 kg/daa. Alle tapene var noe lavere enn gjennomsnittet for overvåkingsperioden.