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.
2018
Abstract
No abstract has been registered
Authors
Klaus Mittenzwei Hugo Storm Thomas HeckeleiAbstract
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.
Authors
Ingeborg KlingenAbstract
No abstract has been registered
Authors
Anastasia Georgantzopoulou Christian Vogelsang Claire Coutris Fabio Polesel Benedek Plosz Kuria Ndungu Patricia Almeida Carvalho Ailbhe MackenAbstract
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.
Abstract
No abstract has been registered
Abstract
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.
Abstract
No abstract has been registered
Authors
Eivind Vangdal Iren Lunde Knutsen Kristin Kvamm-LichtenfeldAbstract
European plums are susceptible to fruit cracking close to harvest. Heavy rainfall may lead to extensive damages leaving open wounds in the fruit flesh. In addition, cuticular fractures were found. Plum cultivar and stage of maturity are two major factors affecting the susceptibility to cracking. In order to reduce the plums’ susceptibility to cracking plum trees were treated with foliar fertilization during the growing season. Experiments included treatment with boron, calcium and nitrogen. Experiments including treatments with different levels of foliar fertilization did not show clear correlations between treatments and cracking in all cultivars. However, in some cultivars, more cuticular fractures were observed in fruits from nitrogen treated trees and less fractures in fruit from calcium or boron treated trees. In these experiments foliar fertilization with nitrogen, calcium or boron did not affect the amount of visible cracks in fruit significantly. Foliar fertilization is often shown to delay ripening. Even though fruit samples were picked at the same maturity stage, the effect of reduced cracking due to boron and calcium treatments could be partly an effect of differences in maturity. To make sure the fruits would develop fractures, unripe plum fruits on the trees were kept in a plastic bag with zip-lock and a few mL of water (to obtain 100% RH) for one week (from two to one week prior to estimated harvest date). In this way, the susceptibility of fruits on trees treated differently could be observed.
Authors
Eivind Vangdal Angela KoortAbstract
The major sources of nutrients to organic grown apple trees are fertilizers made from manure, compost, bone meal, etc. Depending on humidity and temperature in soil and air, the nutrients are dissolved or mineralized and made available to the trees during the growing season. In conventional apple growing, the trees are given mineral fertilizers in early spring to improve the nitrogen status in the trees during flowering for better fruit set. Is it possible in an organic production system to increase the plant available nitrogen in the flowering period by application of liquid N-fertilizers? The standard fertilizer in Norwegian organic fruit growing is dried and pelleted chicken manure with bone meal and vinasse (Marihøne plus; NPK 8-4-5). In these experiments, a liquid fertilizer (Pioner Hi-fruit; NPK 4-1-5) based on vegetable matter plus potassium-vinasse was compared to the standard fertilizer. The liquid fertilizer was applied to the soil as fertigation from 2 weeks before the estimated start of flowering. The dry product was applied 2 weeks prior to flowering. To incorporate the fertilizers into the soil, a mechanical hoer (Orizzonti, Italy) was run in all plots after the application of dry fertilizer. The nitrogen and mineral contents in soil, leaves and fruit were analyzed. The liquid fertilization applied on the soil in the spring gave higher N-contents in soil and trees compared to the dried manure product. However, the increase in N-content was not very strong in the leaf samples. Apples from trees given high doses of liquid fertilizers were greener with less cover colour and higher IAD-indexes. Still they were softer and had less starch than fruit from other treatments.
Abstract
No abstract has been registered