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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.

2026

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Abstract

This report reviews labour representation in mathematical programming models of cattle farms and examines how variable labour costs affect optimal production plans in OPTINORFARM, a Norwegian whole farm optimisation model. Labour is a costly, time-specific and heterogeneous resource: requirements vary by enterprise, farm size, technology and season. Family labour has an opportunity cost through competition with leisure and off-farm work. Existing models differ substantially in their treatment of labour and the coefficients used. We incorprated coefficients for labour requirements varying with livestock numbers and forage area into the OPTINORFARM model, and sensitivity analyses applied hourly labour costs of NOK 0–500. Under a binding milk quota, higher labour costs favoured fewer, higher-yielding dairy cows. At NOK 500, optimal annual yield was 11,000 kg of energy-corrected milk per cow, versus 8,000 kg with no variable labour cost. Higher labour requirements per cow with conventional rather than automatic milking strengthened incentives for higher yields. Results also depended on feed and beef prices, returns from alternative land uses and access to purchased calves for beef production. In suckler-cow farming, raising hourly labour costs from NOK 0 to 500 reduced slaughter ages from 20 to 14 months for bulls and from 17 to 14 months for heifers. The results are based on the case farms studied, but similar responses may be expected on other farms under comparable conditions. Including labour costs reduce the risk of favouring labour-intensive production plans. Labour availability should also be represented to assess whether the production plans are feasible.

Abstract

In Norway, plum fruit is sold for fresh consumption in a similar way as sweet cherry for a high price. Different treatments were tested to ensure high quality at the consumer end. The fruit is normally picked with a range in ripeness. At packaging grading the fruit in different maturity classes for intended sale in shorter (Ripe+) and longer channels (Ripe-) has been partially implemented in the industry. As a further improvement, application of 1-methylcyclopropene (1-MCP) was tested on fruit of the two ripeness categories of two cultivars. After a period of cold storage and simulated shelf-life for two days at 20°C fruits were tasted by a sensory panel. Fruit quality and fungal decay were assessed both after cold storage and simulated shelf-life. It was clear that taste of less ripe fruit was associated with firmer fruit, more acidity and greener taste, and quality of riper fruit was associated with sweetness, higher colour value, softer texture and a higher taste intensity. The panel found that treated Ripe- fruit had a greener taste and flavour and were less juicy and less sweet. In general, quality analysis of less ripe plum fruit of both cultivars showed that they had higher content of acids, were firmer, and had less cover colour after storage compared to riper fruits. Also, treatment with 1-MCP impacted firmness, colour, and acidity. However, the treatment effect was different depending on cultivars and years. In 2022, the effect of 1-MCP was seen for both ripeness categories of ‘Reeves’, but only for Ripe- fruit in 2023. There was no effect of 1-MCP treatments on ‘Mallard’ in 2022, however, there was a slight effect of 1-MCP on firmness, acids and cover colour after self-life test for less ripe plum fruit in 2023. The Ripe+ fruit developed 2-10 times more fungal fruit decay than less ripe fruit. 1-MCP had no effect on development of fungal fruit decay. Preliminary conclusion was that management of fruit maturation is more effective than 1-MCP application in securing consumer end quality.

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Abstract

Natural disturbances such as windthrow, bark beetle outbreaks, root rot, wildfire and snow or ice damage are increasingly affecting temperate and boreal forests under climate change, creating a need for adaptive management to maintain forest resilience and productivity. Decision Support Systems (DSSs) integrating disturbance dynamics can support managers in adjusting management to these evolving risks. This review synthesizes management recommendations derived from DSSs incorporating natural disturbance models in European temperate and boreal forests. The results reveal that most DSSs rely on simulation models applied at strategic spatial and temporal scales, with particular emphasis on windthrow risk, bark beetle outbreak, and root rot damage. Conifer-dominated, even-aged plantations appear most vulnerable to multiple disturbances, whereas mixed-species stands show greater resilience. Simulations underscore that proactive strategies, such as shortening rotation length, species mixing, and targeted thinning, can reduce disturbance risks, but compromise timber revenues and other ecosystem services. Reactive strategies, including salvage logging and sanitary cuttings, address immediate damage but offer limited long-term mitigation. Optimization methods can help mitigate the trade-offs between profitability and forest resilience by minimizing disturbance risk and maximizing economic outcomes. While several DSSs can integrate single disturbances, only few DSSs can simulate interactions among disturbance models and climate scenarios. Complex data requirements constrain DSS application for operational forest management, restricting their use to researchers. Future DSS development should prioritize simple, applicable and accessible solutions while integrating advanced models capable of addressing diverse disturbance regimes. By leveraging advanced DSSs, forest managers can enhance forest resilience amid increasing climate-driven disturbance pressures.

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Abstract

Sonchus arvensis L. is a perennial weed increasingly abundant in northern Europe, associated with organic farming and soil cultivation. The resprouting potential after disturbance and its subsequent development and growth under different site conditions remain unclear. This study investigated the effects of aboveground biomass removal of S. arvensis in Rostock (Germany), Jokioinen (Finland), and Ås (Norway). In the start year, 5 cm  S. arvensis root fragments (ramets) were planted in spring under semi‐field conditions, with five replicates per treatment stage. The treatment stages were defined according to plant development stages at which aboveground biomass was removed by cutting: bud, flower, seed‐head, wilt and an uncut control. Plant development was assessed as BBCH stage in the autumn of the start year and in summer of the subsequent year. Plant growth was assessed in the subsequent year as below‐ and aboveground biomass (dry weight), number of shoots and leaves. In Ås, some ramets failed to resprout after cutting treatment in the start and subsequent year, whereas all plants resprouted in Rostock and Jokioinen. In general, biomass was higher in Rostock than in Jokioinen and Ås. Removing biomass in the start year affected plant development within the same, but not in the subsequent year. Biomass removal at the treatment stages bud and flower reduced plant growth, whereas it was hardly affected by removal at seed‐head or wilt stages compared to the uncut control. Overall, further development stages reached after resprouting in the start year were associated with reduced growth in the subsequent year.

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Abstract

Recycled nutrient fertilizers (RNFs) are central to circular nutrient management, yet their agronomic performance is often evaluated using yield‐based metrics alone. This study evaluated yield‐efficiency trade‐offs of pelleted waste‐derived RNFs using nitrogen use efficiency (NUE) and relative agronomic effectiveness (RAE) as complementary indicators. In a 4‐month controlled glasshouse pot experiment with a forage grass mixture ( Lolium perenne , Lolium multiflorum‐estanzuela , Festuca rubra , and Lolium hybridum ), two recycled fertilizers (BADSS [Biochar–ash–digestate–sewage‐sludge pellet (“black pellet”)] and SADSS [Shavings–ash–digested‐sewage‐sludge pellet (“yellow pellet”; chromium‐free bovine shavings)]), the same pellets combined with a fermented bakery–dairy amendment containing effective microorganisms (EM), and a commercial cow manure granulate were evaluated across a pellet‐N gradient of 20–370 kg N/ha over four sequential harvests. The fermented amendment supplied an additional 0.3612 g N/pot. Under these controlled conditions, RNF formulations matched or exceeded the reference fertilizer in cumulative biomass, with SADSS+EM (SADSS combined with the fermented bakery–dairy amendment containing effective microorganisms) producing the largest yield responses and RAE values. NUE declined strongly as N input increased. Accounting for N supplied by the fermented amendment substantially lowered calculated NUE for the amended treatments, showing that apparent performance gains reflected both co‐supplied nutrients and treatment‐specific interactions. Because the amendment also contained organic material and other constituents and no nutrient‐matched carrier control was included, the experiment does not isolate a microorganism‐specific effect. Non‐amended SADSS showed the most balanced relationship between RAE and NUE across application rates. These results indicate a yield‐efficiency trade‐off under controlled conditions and highlight the need for transparent accounting of all amendment‐derived nutrient inputs before field‐scale inference.

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Abstract

Mean concentrations of pollutants and nutrients are frequently used in the classification of water bodies under the European Commission Water Framework Directive. Turbidity can be used as a proxy for several particle-associated substances. We used three years of sensor turbidity data in each of 10 Nordic streams to assess the uncertainty in the annual arithmetic mean concentration of turbidity when sampling weekly, fortnightly, or monthly. On average, weekly sampling produced an uncertainty of 17±9% for all streams, whereas monthly sampling increased this to 40±19%. We then developed a multiple linear model that shows how the uncertainty in annual mean turbidity increases with decreasing sampling frequency, decreasing catchment size, and increasing proportion of agricultural land in the catchment. As an example, a river of 800 km 2 catchment area and 20% agricultural land will need 29 samples a year to give a mean annual turbidity within 10% uncertainty, but a stream of 10 km 2 catchment area and 80% agricultural land will need 95 samples to achieve the same uncertainty. Turbidity was a suitable proxy for total phosphorus in seven of the 10 streams. The range of the annual mean total phosphorus concentration was compared with the environmental objective (good water quality) in each river. The results highlight that when the estimated mean total phosphorus concentration is close to the concentration of the environmental objective, an infrequent sampling strategy can lead to false water quality classification. .

Abstract

Core rot in apple has only been considered a problem in a limited number of cultivars and has not been a focus in Norway, or in many other countries. There is currently a high demand for apple juice and cider in Norway. As core rot is not detectable on the fruit surface until the rot reaches the outer fruit flesh, it is possible for infected fruit to be used for juice without noticing the rot. Since Fusarium spp., one of the known causes of core rot, is a known producer of mycotoxins, precautionary investigations are needed. Over several seasons it was found that both pre- and postharvest rot of Fusarium spp. were common on most of the cultivars grown in Norway. As in other countries, Fusarium avenaceum has dominated so far, but Fusarium paeoniae was also identified on apple. Inoculation experiments with attached fruit and in storage were successful both in establishing core rot and detecting different mycotoxins from the fruit. There were differences between isolates of F. avenaceum in both the type of mycotoxins produced and the amount. A potential life cycle for Fusarium spp. on apple fruit in Norway is suggested, and possible ways of reducing the incidence both pre- and postharvest are discussed.