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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.

2025

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Abstract

Naturally regenerated seedlings of Quercus petraea (Mattuschka) Liebl. are often outcompeted by tree species such as Fagus sylvatica L. and Carpinus betulus L., and understorey species like Rubus subg. Rubus. Since plant growth is fundamentally driven by photosynthetic capacity and efficiency, the competitive dynamics between species are influenced by their ability to adapt to varying light conditions through morphological and physiological plasticity. To explore these adaptations, we measured a number of variables indicating growth performance or potential of 60 12-year-old seedlings of Q. petraea, F. sylvatica, and C. betulus as well as individuals of R. subg. Rubus along a gradient of canopy openness and thus radiation. These variables included: a) key leaf traits, including specific leaf area (SLA) and leaf nitrogen (N) content, b) different photosynthesis measurements under constant and fluctuating light, and c) annual shoot length, total height and root collar diameter. Solar radiation was quantified as total site factor (TSF). In all four species, an increase in leaf N content was observed with increasing TSF, which was accompanied by an increase in maximum photosynthetic rate (A ) and growth. However, while this increase was continuous in C. betulus and R. subg. Rubus, a significant increase in A max and growth in Q. petraea and F. sylvatica occurred only in the radiation ranges between 1 % and 20 % and 50–70 % TSF. Measurements of photosynthesis in relation to simulated lightflecks suggest that leaves of Q. petraea are better adapted to prolonged high photosynthetic photon flux density (PPFD) exposure than to fluctuating light. Under these light conditions, especially at TSF levels > 60 %, Q. petraea showed a higher photosynthetic performance than F. sylvatica and C. betulus, in addition to comparable diameter and height growth. To promote Q. petraea regeneration against F. sylvatica and C. betulus competition and reduce necessary vegetation control interventions, we recommend radiation levels > 60 % TSF after the initial establishment phase, when oak seedlings have reached a height of about 0.8 m.

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Abstract

Single-class object detection, which focuses on identifying, counting, and tracking a specific animal species, plays a vital role in optimizing farm operations. However, dense occlusion among individuals in group activity scenarios remains a major challenge. To address this, we propose YOLO-SDD, a dense detection network designed for single-class densely populated scenarios. First, we introduce a Wavelet-Enhanced Convolution (WEConv) to improve feature extraction under dense occlusion. Following this, we propose an occlusion perception attention mechanism (OPAM), which further enhances the model’s ability to recognize occluded targets by simultaneously leveraging low-level detailed features and high-level semantic features, helping the model better handle occlusion scenarios. Lastly, a Lightweight Shared Head (LS Head) is incorporated and specifically optimized for single-class dense detection tasks, enhancing efficiency while maintaining high detection accuracy. Experimental results on the ChickenFlow dataset, which we developed specifically for broiler detection, show that the n, s, and m variants of YOLO-SDD achieve AP50:95 improvements of 2.18%, 2.13%, and 1.62% over YOLOv8n, YOLOv8s, and YOLOv8m, respectively. In addition, our model surpasses the detection performance of the latest real-time detector, YOLOv11. YOLO-SDD also achieves state-of-the-art performance on the publicly available GooseDetect and SheepCounter datasets, confirming its superior detection capability in crowded livestock settings. YOLO-SDD’s high efficiency enables automated livestock tracking and counting in dense conditions, providing a robust solution for precision livestock farming.

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Abstract

Empirical field data and simulation models are often used separately to monitor and analyse the dynamics of insect pest populations over time. Greater insight may be achieved when field data are used directly to parametrize population dynamic models. In this paper, we use a differential evolution algorithm to integrate mechanistic physiologicalbased population models and monitoring data to estimate the population density and the physiological age of the first cohort at the start of the field monitoring. We introduce an ad hoc temperature-driven life-cycle model of Bemisia tabaci in conjunction with field monitoring data. The likely date of local whitefly invasion is estimated, with a subsequent improvement of the model’s predictive accuracy. The method allows computation of the likely date of the first field incursion by the pest and demonstrates that the initial physiological age somewhat neglected in prior studies can improve the accuracy of model simulations. Given the increasing availability of monitoring data and models describing terrestrial arthropods, the integration of monitoring data and simulation models to improve model prediction and pioneer invasion date estimate will lead to better decision-making in pest management.

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Abstract

The interaction of cellulose paper with water is a major hindrance to its broader application. This study, which introduces a novel approach to understand water vapor difusion in both untreated and treated paper, aims to identify the difusion coefcient, a crucial property in improving the hydrophobicity of paper. The treatment process utilized an aqueous solution of starch or starch modifed with methyltrimethoxysilane (MTMS). While the initial sorption method is frequently used to determine the difusion coefcient, this study found that it could lead to signifcant errors due to the non-Fickian behavior exhibited by lignocellulosic materials. This behavior causes that the hygroscopic equilibrium is not instantly obtained by surface of paper. It also induces slowing down moisture difusion in its fnal stage due to molecular relaxation. For the frst time, the modifed convective boundary condition was introduced into the moisture difusion model in paper materials. The results from vapor sorption experiments demonstrated this non-Fickian behavior, particularly at high values of air relative humidity. The study also revealed that the commonly applied frst kind boundary condition is not applicable, even for thin paper samples, inhibiting the use of the initial sorption method for determining the difusion coefcient. While the treatment with starch and MTMS signifcantly improved the hydrophobic properties of paper, it didn’t alter substantially its hygroscopic properties, potentially due to not blocking active sorption sites of cellulose fbers. This research underscores the need for further investigation into the chemical modifcation of cellulose fbers to improve the hydrophobicity of paper.

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Abstract

How to build a sustainable seaweed industry is important in Europe’s quest to produce 8 million tons of seaweed by 2030. Based on interviews with industry representatives and an expert-workshop, we developed an interdisciplinary roadmap that addresses sustainable development holistically. We argue that sustainable practices must leverage synergies with existing industries (e.g. IMTA systems, offshore wind farms), as the industry develops beyond experimental cultivation towards economic viability.

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Abstract

Thirty-seven turfgrass samples expressing dollar spot symptoms were collected in summer 2020 on golf courses in Sweden, Denmark, United Kingdom, Germany, Portugal, and Spain. The fungi were isolated at Norwegian Institute of Bioeconomy Research (NIBIO) Turfgrass Laboratory (Norway) and sent for molecular identification using sequencing of regions of ITS (internal transcribed regions of the ribosomal DNA) and calmodulin. Clarireedia homoeocarpa was identified in four turfgrass samples and Clarireedia jacksonii was identified in 11 turfgrass samples. From seven turfgrass samples, the isolated fungi were not Clarireedia spp., but Waitea circinata, Fusarium culmorum, and Fusarium oxysporum. This suggests dollar spot is not always accurately identified from foliar symptoms in the field.

Abstract

This article presents a novel, ultralight tree planting mechanism for use on an aerial vehicle. Current tree planting operations are typically performed manually, and existing automated solutions use large land-based vehicles or excavators which cause significant site damage and are limited to open, clear-cut plots. Our device uses a high-pressure compressed air power system and a novel double-telescoping design to achieve a weight of only 8 kg: well within the payload capacity of medium to large drones. This article describes the functionality and key components of the device and validates its feasibility through experimental testing. We propose this mechanism as a cost-effective, highly scalable solution that avoids ground damage, produces minimal emissions, and can operate equally well on open clear-cut sites as in denser, selectively-harvested forests.