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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

Abstract

Forest transpiration is often quantified by scaling up stem sap flow measured on a few trees within a stand. This procedure carries uncertainty related to the (ill)representativeness of the sampled trees for the entire stand, often comprising several thousand transpiring trees. Here, we explored the uncertainty reduction potential afforded by increasing the number of sampled trees within the stand – not by costly sap flow monitoring equipment – but by point dendrometers measuring sub-daily fluctuations in stem radii which partially correlate with xylem water movement (i.e., sap flow). Using measurements collected in a forest dominated by even-aged spruce trees over two growing seasons, we built an empirical model for estimating hourly sap flow from individual trees equipped with point dendrometers, then applied it to estimate the daily transpiration of the stand both with and without trees equipped with point dendrometers. We found that the expanded tree sample size reduced the uncertainty of the stand-level estimate by 31–37 %, suggesting that the benefit afforded by increasing the stand representativeness outweighed the cost of introducing modeling error. Given their relative simplicity and affordability, we encourage additional investigations into the use of point dendrometers for studying tree water relations and water consumption patterns of entire forested stands.

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Abstract

This study investigated the incorporation of various waste materials including wastepaper, Tetra Pak, wood chips and scrap tire fluff into flue gas desulfurization (FGD) gypsum and cement mortar matrices to produce sustainable composite materials. Four distinct composite types based on the waste materials were developed and evaluated for selected properties including thermal and acoustic insulation. The proportion of the waste materials was varied between 10 and 40 vol% of the base matrix. The compressive strength of the filled gypsum composites was in the range of 4.17–10.39 N/mm² while the pure gypsum was 11.38 N/mm². The addition of the wastes in gypsum composites reduced compressive strength by about 10% for the best recipe and as large as 60% for the worst combination. However, the measured strength still exceeds the strength of typical gypsum wallboard with a compressive strength of about 3–4 N/mm² for whole-board crushing tests and it is much lower for point loads. The normal-incidence sound absorption coefficient indicated that the waste-filled samples absorbed around 80% of the incident sound energy between 2000 and 3000 Hz, comparable to some commercial acoustic foams. The results highlight the potential of utilising these waste-based composites in environmentally friendly construction applications. Depending on the waste type and matrix used, the results revealed trade-offs between multi-functional performance and sustainability benefits.

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Abstract

Potato field management in Europe is already optimized for high production and tuber quality; however, numerous environmental challenges remain if the industry is to achieve “green economy” targets, such as less resources utilized, and less nitrate leached to the environment. Strategic co-scheduling irrigation and nitrogen (N) fertilization might increase resource use efficiency while minimizing reactive losses such as nitrate leaching. This study aimed to quantify the combined effect of irrigation and N fertilization on potato production, growth, and resource use efficiencies. A field experiment was conducted from 2017 to 2019 on a coarse sandy soil in Denmark, with a drought event occurring in 2018. Full (Ifull, maximized), deficit (Idef, 70–80 % of Ifull) and low irrigation treatments (Ilow, minimized amount to keep crop survival), each under full (Nfull, maximized) and variable (Nvar, variable amount according to the crops’ needs) N fertilization were applied. The analyses results show that Ilow limited potato growth under a drought-heat event; otherwise, potato growth was comparable between Ifull and Idef treatments, with 31–32 % higher irrigation efficiency (IE) under Idef than under Ifull. Nitrate leaching was variable and not significantly different among the treatments, being in general 9–13 % lower under Idef in absolute terms than under Ifull. Unexpectedly, outcomes from Nvar were statistically lower compared to those from Nfull. Radiation use efficiencies (RUEs) from Ilow and Nvar were significantly lower than from Ifull and Idef (14–19 %), and from Nfull (9–11 %). N use efficiencies (NUE) were comparable between N fertilization treatments but significantly different among different irrigation treatments. Overall, this study confirms that Idef is the best irrigation strategy. Future efforts should focus on developing improved approaches for detecting in-season crop N status and further quantifying N requirements, as well as promoting the co-scheduled management of irrigation and N fertilization. Remote sensing approaches have great potential to assist with this.

2025

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Abstract

Integrated Pest Management (IPM) has been mandatory in Norway since 2015, as a strategy to reduce pesticide use and promote more sustainable agriculture. Studies show that implementation of IPM at farm level remains context-dependent, but so far no study on Norwegian fruit farming system had yet been conducted. This thesis aims to explore how Norwegian fruit farmers understand and apply IPM principles and what factors influence their adoption. A total of nine semi-structured interviews were conducted in two major fruit regions (Hardanger and Lier). The findings show that while several IPM principles are applied, especially preventive and non chemical methods, other principles are less implemented by farmers. IPM adoption is shaped by on-farm factors including technical constraints, infrastructures, economic concerns, social interactions, health and environmental awareness, as well as factors specific to the farmer. External influences such as national and European policies, market pressures, advisory and research services, and farmers’ networks also play a major role. These findings highlight the need for context-sensitive support or the need to address novel research gaps in IPM-related studies, especially in the Norwegian fruit farming context.

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Abstract

The re-usage of waste can strongly impact the environmental footprints of both the biogas production facility as waste-source and a receiver system as a greenhouse production. The waste product of the biogas-reactors as e.g. liquid and solid fertiliser. In a combined production with heated greenhouse-production both the main product biogas as well as its side products as water and the digestate are valuable compounds for a greenhouse production system. The impact of main and side products on the greenhouse produce depends on location, greenhouse type, and overall composition of the system. We analysed and modelled biogas-production of two biogas-greenhouse scenarios in Italy and Norway with each their specific input and outputs. For the two existing locations in Northern Italy (Trento; 46°04′N LAT) and Southern Norway (Sandefjord; LAT 59°08′N), and for a hypothetical location geographically between them (Berlin, Germany; 52°52′N) we analysed three scenarios of agricultural waste with either apple-juice production waste, waste from husbandry, or a mix of these two wastes; and their impact on environmental foot-prints of a tomato production in greenhouses. Scenarios were simulated with a greenhouse simulator, while simulation data was used as input to a consequential life cycle assessment. Functional unit was 1kg of tomato as gate.