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
Sammendrag
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Sammendrag
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Forfattere
Geir-Harald StrandSammendrag
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Forfattere
Klaus Mittenzwei Hugo Storm Thomas HeckeleiSammendrag
Seeking the answer to the question of how farmers allocate their limited labor resources has a long tradition in the agricultural economics literature (Schultz 1990, Benjamin 1992). The role of off-farm income to close the income gap between farm households and non-farm households has been emphasized by various scholars (e.g. Schmitt 1989, Gardner 1992, Mishra et al. 2002). Ahearn et al. (2006) focus on the role of government subsidies on the allocation decision. This chapter contributes to this literature. In particular, we investigate the relationship of farmers’ decisions to combine farm income with off-farm wage income and to what extent this affects their total household income. To this end, we combine taxpayer information and agricultural data at the farm household level to study labor decisions and the income of Norwegian farm households and compare with the income situation of all households. Using data of almost 40 000 farm households for the year 2009, we find that farm households obtain an income that is on average larger than that of all Norwegian households. However, there is a large variation. Descriptive statistical analysis looking at joint distributions of key structural variables, policy support and income at farm level provides unique information.
Forfattere
Ingeborg KlingenSammendrag
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Forfattere
Anastasia Georgantzopoulou Christian Vogelsang Claire Coutris Fabio Polesel Benedek Plosz Kuria Ndungu Patricia Almeida Carvalho Ailbhe MackenSammendrag
The increase in production and use of Ag and TiO2 nanomaterials has led to their release in wastewater streams and subsequently in the environment. Nanoparticles (NPs) can undergo transformations in environmental media such as wastewaters leading to an alteration in behavior, bioavailability and toxicity that may differ from their pristine counterparts and make predictions challenging. In this context, the overall goal of the study was to elucidate (i) the behavior and transformation of Ag and TiO2 NPs in realistic matrices such as wastewater effluents and activated sludge and (ii) the subsequent effects of transformed particles in comparison to their pristine counterparts. In this study, a laboratory-scale wastewater treatment system was established and combined with a battery of ecotoxicological assays and characterization techniques. The system contained activated sludge and was operated as a pre-denitrification system fed with synthetic wastewater spiked daily with 10 µg Ag NPs/L (PVP coated, 25 nm, nanoComposix) and 100 µg TiO2 NPs/L (nominal primary size of 5 nm, NM-101, JRC) over a period of 5 weeks. During that period the effluents were collected weekly and the excess sludge was stored for the evaluation of terrestrial toxicity. Samples from all reactors and effluents were collected weekly and analyzed by sequential filtration and ICP-MS to determine the partitioning of NPs and their transformation products. Transmission electron microscopy and sp-ICP-MS were performed on selected samples. The effects of aged particles were assessed using a battery of bioassays including freshwater and marine algae (growth inhibition and reactive oxygen species -ROS- formation), crustaceans, as well as in vitro models of relevance for NP toxicity assessement (RTgill-W1 cell line, effects on metabolic activity, epithelial integrity, ROS formation, gene expression). The extent of the observed effects was dependent on the organism exposed, with bottom feeding organisms and algae being more sensitive, while the in vitro model was a good tool for environmental samples. Furthermore, the biosolids generated from the lab-scale continuous system were used in terrestrial microcosm experiments, giving insight into the fate and potential accumulation in a model terrestrial system. Experimental data generated from the continuous-flow operation of the activated sludge system and the targeted batch experiments will be used to model the fate and the removal of NPs.
Sammendrag
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Sammendrag
In anaerobic digestion, studies of feeding frequency have produced conflicting results. Hence, the effect of feeding frequency on process variables and microbial community structure was investigated by comparing a laboratory-scale digester fed steam exploded food waste 10 times daily vs. one fed an equivalent amount once daily. The Frequently Fed Digester (FFD) produced on average 20% more methane and had lower effluent concentrations of long-chain fatty acids. Greater daily fluctuations in acetate, pH and biogas production rate could explain the lower specific methane yield and β-oxidation. Feeding frequency also influenced the microbial community whereby Tenericutes (42%) dominated in FFD but Firmicutes (31%) was most abundant in the Daily Fed Digester (DFD). Feeding frequency effects are therefore postulated to occur more often in digesters fed labile feedstocks at high organic loading rates.
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Sammendrag
Det ble i 2016 dyrket vårhvete i Bye-feltet, og det ble bare gjødslet med mineralgjødsel. Nitrogentilførselen (19,7 kg/daa) lå over gjennomsnittet for vårhvete i perioden 1996–2015 (16,6 kg/daa), mens fosfortilførselen (1,6 kg/daa) var det halve av gjennomsnittet. Feltet høstpløyes årlig.