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.
2011
Authors
Anne-Grete Roer Hjelkrem Ottar Michelsen Trond Henriksen Audun Korsæth Anders Hammer StrømmanAbstract
No abstract has been registered
2010
Abstract
Studying the winter survival of forage grasses under a changing climate requires models that can simulate the dynamics of soil conditions at low temperatures. We developed a simple model that simulates depth of snow cover, the lower frost boundary of the soil and the freezing of surface puddles. We calibrated the model against independent data from four locations in Norway, capturing climatic variation from south to north (Arctic) and from coastal to inland areas. We parameterized the model by means of Bayesian calibration, and identified the least important model parameters using the sensitivity analysis method of Morris. Verification of the model suggests that the results are reasonable. Because of the simple model structure, some overestimation occurs in snow and frost depth. Both the calibration and the sensitivity analysis suggested that the snow cover module could be simplified with respect to snowmelt and liquid water content. The soil frost module should be kept unchanged, whereas the surface ice module should be changed when more detailed topographical data become available, such as better estimates of the fraction of the land area where puddles may form.
Abstract
Docks are among the most important perennial weeds in grasslands throughout the world and the need for more effective control methods is especially crucial in organic forage production. To find more effective control methods, field trials over 2 years at 4 Norwegian locations, were carried out mainly as a full-factorial design, including factors expected to reduce docks significantly. (i) Date of grassland establishment: may be important for preventing/decreasing the flush of seedlings from seeds as well as shoots from root fragments.(ii) False seedbed preparation: to decrease soil seed bank. (iii) Use of nurse crop (cover crop) to increase competitiveness against Rumex seedlings. (iv) Cutting the taproot, using a rotary tiller before ploughing, or the "dock-plough" (a skimmer modified to cut roots in the entire furrow width at ca 7 cm depth): as new shoots mostly come from the neck and the upper 5 cm of the taproot. (v) Ploughing depth and skimming: to decrease shoots from root fragments. Weed development was assessed as the number of emerging Rumex seedlings and plants sprouting from root fragments. Results indicated that frequently more plants emerged from seeds than from root fragments. Neither renewing the grassland in summer, nor the use of the rotary tiller or the "dock plough" reduced the number of docks in the renewed grasslands. The use of the false seedbed and nurse crop, at some locations and years, reduced the number of docks in the renewed grasslands. Deep ploughing (24cm) reduced the number of Rumex plants from roots by 65% percent compared to shallow ploughing (16cm). Furthermore, the use of a skimmer reduced the number of docks sprouting from roots by 28%. Among the investigated factors, competitiveness, false seedbed and ploughing depth, as well as ploughing quality, seems to be the most promising factors for reducing the number of docks in renewed grassland.
Abstract
No abstract has been registered
2008
Abstract
In Norway, public procurement of food to youth is not well developed in comparison to many other European and Scandinavian countries. School meals are only offered in very few primary schools, and the common school meal is a packed lunch (sandwiches) brought from home, consumed in the class room. Subscription schemes for milk were introduced around 1970, and for fruit around 1995. Organic milk and fruit is offered only in some regions. Since 2007, fruit is served without payment in all schools with a lower secondary level (class 8-10 or 1-10). This effort was introduced as a first step to develop a free school meal in all public schools, which is a goal of one of the political parties in the current government. As in many other European countries, free school meals were offered (especially to poor children) in schools in the larger Norwegian cities around 1900. However, these meals were criticised for being unhealthy, and replaced by whole grain bread, milk and vegetables around 1930. Increasing private wealth, and increased demand for investments in school buildings, books etc changed the public priority and free school meals disappeared in Oslo around 1960. Today, there is not a general agreement about the optimal school meal composition, and whether or not the meals should be funded by the public. However, the increasing length of the school day and unsatisfactory scores of Norwegian pupils in international comparison tests (e.g. PISA) makes the school meal sector highly relevant in the public debate. Three cases that will be studied in a research project about public organic food procurement for youth are briefly described: The municipality of Trondheim, Øya music festival in Oslo and the Air Force Academy. (Increased) serving of organic food is an important aim in all these cases, and young people are an important target group. The report is produced within the project “innovative Public Organic food Procurement for Youth”, iPOPY, and will be updated and revised during the project period (2007-2010).
Abstract
No abstract has been registered
2007
Abstract
No abstract has been registered
2006
Abstract
No abstract has been registered
Abstract
Conventional farmers converting to organics have contributed to most of the rapid expansion of organic farming in recent years. The new organic farmers may differ from their more established colleagues, which may have implications for the development of the organic farming sector and its distinctiveness vis-a-vis conventional production and marketing practices. The aim of this study was to explore Norwegian organic dairy farmers' personal and farm production characteristics, farming goals, conversion motives, and attitudes to organic farming, grouped by year of conversion (three groups). A postal survey was undertaken among organic dairy farmers (n=161). The results show that the newcomers (converted in 2000 or later) were less educated than the early entrants (the so-called 'old guard') who converted in 1995 or earlier. The frequency of activities like vegetable growing and poultry farming among the old guard was high. The late-entry organic herds were fed with more concentrates and had a higher milk production intensity, showed a higher incidence of veterinary treatments and less frequent use of alternative medicine than the herds of the two earlier converting groups. For all groups of farmers, the highest ranked farming goals were sustainable and environment-friendly farming and the production of high-quality food. Late entrants more often mentioned goals related to profit and leisure time. On average, the most frequently mentioned motives for conversion were food quality and professional challenges. The old guard was more strongly motivated by food quality and soil fertility/pollution issues than the others, whereas financial reasons (organic payments included) were relatively more important among the newcomers. All groups held very favorable views about the environmental qualities of organic farming methods, albeit with different strengths of beliefs. Even though trends towards more pragmatic and business-oriented farming were found, the majority of the newcomers were fairly committed.
2005
Abstract
About 18% of the conventional dairy and cash crop farmers in Norway are considering to, and 4% are planning to convert to organic farming during the next five years. ...