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The edoc server is the Open Access publication server and institutional repository of the Humboldt-Universität zu Berlin. It is available to university members for the publication of academic work as a first or second publication. In addition to text publications, research data can also be published via the edoc server. These publications are available to the general public worldwide, free of charge and for the long term.
The University Library supports and advises all members of the University in all matters relating to academic publishing:
- Literature search and online resources
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- Publishing on the edoc server
If you have any questions, please contact the Open Access team or the Electronic Publishing working group.
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Recent Submissions
2023-12-07Zeitschriftenartikel
Time-domain modeling of interband transitions in plasmonic systems
(Mathematisch-Naturwissenschaftliche Fakultät) Pfeifer, Max; Huynh, Dan-Nha; Wegner, Gino; Intravaia, Francesco; Peschel, Ulf; Busch, Kurt
Efficient modeling of dispersive materials via time-domain simulations of the Maxwell equations relies on the technique of auxiliary differential equations. In this approach, a material’s frequency-dependent permittivity is represented via a sum of rational functions, e.g., Lorentz poles, and the associated free parameters are determined by fitting to experimental data. In the present work, we present a modified approach for plasmonic materials that requires considerably fewer fit parameters than traditional approaches. Specifically, we consider the underlying microscopic theory and, in the frequency domain, separate the hydrodynamic contributions of the quasi-free electrons in partially filled bands from the interband transitions. As an illustration, we apply our approach to gold and demonstrate how to treat the interband transitions within the effective model via connecting to the underlying electronic band structure, thereby assigning physical meaning to the remaining fit parameters. Finally, we show how to utilize this approach within the technique of auxiliary differential equations. Our approach can be extended to other plasmonic materials and leads to efficient time-domain simulations of plasmonic structures for frequency ranges where interband transitions have to be considered.
2023-06-10Zeitschriftenartikel
Field path optimization to reduce headland and turning maneuvers at regional scales: automated detection of cultivation direction in the state of Brandenburg, Germany
(Lebenswissenschaftliche Fakultät) Donat, Marco; Geistert, Jonas; Grahmann, Kathrin; Bellingrath-Kimura, Sonoko D.
Path planning for optimized field-work pattern is an important task within precision farming. The decision on a particular direction and path to cultivate and manage the field is complex and can significantly affect working time, energy consumption, soil compaction and yield. This study proposed a new method for automated detection of the current cultivation direction of several thousands of agricultural fields and compared the current cultivation direction with an optimized cultivation direction generated from a path planning algorithm. Airborne imagery from 2019 was analyzed using a modified Gabor filter. The identification takes place on a sub-plot level and can therefore detect small-scale differences in cultivation direction within fields. The method for identification of current cultivation direction had a high success rate of 87.5%. Fields with a high potential to save turning maneuvers and to reduce the area of headland were identified. From 3410 fields, a total of 58162 turning maneuvers and 507 ha headland were saved. This corresponds to 14.1% of all turning maneuvers and 7.6% of the total headland area for all analyzed fields in Brandenburg. A high optimization potential was demonstrated for field paths when efficient processing directions are taken into account. The method can be extended to the analysis of satellite imagery and thus offers the possibility of identifying current cultivation directions with a high spatial and temporal resolution. In future, this knowledge can be embedded within decision support systems for real-time optimization of field machinery path planning to support sustainable cropping practices.
2023-11-14Zeitschriftenartikel
Farmers’ behavioural determinants of on-farm biodiversity management in Europe: a systematic review
Klebl, Fabian; Feindt, Peter H.; Piorr, Annette
Agricultural intensification and landscape homogenisation are major drivers of biodiversity loss in European agricultural landscapes. Improvements require changes in farming practices, but empirical evidence on farmers’ motivations underlying their on-farm biodiversity management remains fragmented. To date, there is no aggregated overview of behavioural determinants that influence European farmers’ decisions to implement biodiversity-friendly farming practices. This study aims to fill this knowledge gap by conducting a systematic literature review of 150 empirical studies published between 2000 and 2022. We identified 108 potential determinants of farmers’ behaviour, which were integrated into a multilevel framework. The results show that the farmers’ decisions are complex and often non-directional processes, shaped by numerous external (at a society, landscape, community, and farm level) and internal factors. These factors are embedded in regional and cultural contexts. However, the analysis of study sites indicates that the spatial coverage of scientific evidence on biodiversity-friendly farming measures is uneven across Europe. Given the diversity of local and socio-cultural conditions, there is a need for public policies, including the European Union’s Common Agricultural Policy, to address more specifically determinants encouraging biodiversity-friendly farm management. This entails reflecting culture-specific perspectives and incorporating experiential knowledge into multilevel policy design processes, as well as offering regionally adapted advice on measure implementation and biodiversity impacts.
2022-10-25Zeitschriftenartikel
Infected grasses as inoculum for Fusarium infestation and mycotoxin accumulation in wheat with and without irrigation
(Lebenswissenschaftliche Fakultät) Gerling, Marina; Petry, Laura; Barkusky, Dietmar; Büttner, Carmen; Müller, Marina E. H.
Grasses growing next to agricultural fields influence the Fusarium abundance, the species composition, and the mycotoxin accumulation of wheat plants, especially the field parts directly adjacent to grasses, are highly affected. Grasses are a more attractive and suitable habitat for Fusarium fungi compared to other arable weeds and occur at mostly every semi-natural landscape element (e.g., kettle holes, hedgerows, field-to-field-borders). In our study, we analyzed the ability of a highly Fusarium infected grass stripe ( F. graminearum , F. culmorum , F. sporotrichioides ) to infect an adjacent wheat field with these species. Results show that the primary inoculated Fusarium species were as well the dominant species isolated from the wheat field. Regarding transects originating from the grass stripe going into the field, the results demonstrate that wheat ears next to the infected grass stripe have a higher Fusarium abundance and furthermore show higher mycotoxin accumulation in the wheat kernels. This effect was highly promoted by irrigation. Therefore, grass stripes next to arable fields must be considered as reservoirs for fungal infections and as a source for a contamination with mycotoxins.
2023-03-17Zeitschriftenartikel
Upscaling agroforestry in the tropics through actor-networks: a comparative case study of cacao farming systems in two regions of Colombia
Rodríguez, Tatiana; Bonatti, Michelle; Löhr, Katharina; Bravo, Aura; Del Río, Martha; Lana, Marcos; Sieber, Stefan
Agroforestry systems (AFS) upscaling has the potential to integrate sustainability and resilience objectives into agriculture. However, this is a daunting task requiring multi-actor collaboration across public and private sectors at multiple governance levels, coupled with innovative approaches to jointly managing AFS knowledge. Understanding such multi-actor interactions from a network perspective may help to unravel how social structures, created by relational patterns enhance or hinder AFS upscaling. Our paper aims to comparatively explore the role of regional actor-networks on AFS upscaling for a selected farming system. By conducting semi-structured interviews, we collected information about the ties of 86 actors supporting cacao agroforestry systems (CAFS) across two regions of Colombia. We use social network analysis (SNA) to comparatively visualize and understand the general structure of these networks, find relational patterns between the diverse categories of actors involved, and identify a set of key players bridging the majority of the actors within these networks. We find highly centralized networks that connect multiple actors by a low number of mostly non-reciprocal ties. Within these networks, we identify a predominance of bridging ties over bonding ties, homophily patterns among research and education institutions, and heterophily configurations among farmer-based organizations. We also find that the composition of the sets of key actors and the platforms where they converge varies substantially from region to region due to decentralized agricultural policies and differing characteristics across regions. Our approach provides key entry points for promoting multi-actor coalitions that can effectively expand the benefits of AFS in tropical agricultural systems.