TY - THES A1 - Coort, Katharina T1 - Rhizosphere and endophytic colonization of cover crops by entomopathogenic fungus Metarhizium brunneum N2 - Species of the entomopathogenic fungal genus Metarhizium (Ascomycota: Hypocreales) are pathogenic to many arthropods, a trait that is utilized in agricultural pest control. Next to their pathogenic lifestyle, many Metarhizium species show plant root association. Due to the potential to improve efficiency in pest management by increasing abundance and persistence in the soil, and positively influence plant development by facilitating nutrient uptake as well as biotic and abiotic stress tolerance (e.g., droughts and diseases), interactions of EPF with plant roots represent valuable characteristics. EPF species Metarhizium brunneum is known for its virulence against wireworms, a major insect pest for example in potato farming, and has shown its root associating abilities before. To investigate its potential in cover crop applications, a recent approach to improve field efficiency in wireworm control, this experiment studied its root associations with seven different cover crop species. In a greenhouse pot trial, one-week-old seedlings were inoculated with M. brunneum isolate Cb 15-ǀǀǀ followed by bulk soil, rhizosphere, and root sampling 8 weeks later, and plating them onto semi selective nutrient agar. Bulk soil and rhizosphere populations were assessed by CFU counting while endophytic root colonization was determined by identification of colonies growing from root cut surfaces. Rhizosphere populations were on average 54 % higher than bulk soil ii populations, indicating a substantial root association. Endophytic root colonization was observed with 4 out of 7 species. Amongst them were the two Brassicaceae species Raphanus sativus and Sinapis alba as well as grass species Lolium multiflorum which showed the overall highest root associations with M. brunneum. Rhizosphere populations of S. alba were noticeably lower than for all other species while still showing one of the highest internal root colonization rates which potentially originates from species-specific allelochemicals in the rhizosphere. There was a significant negative correlation between Metarhizium populations in the bulk soil and endophytic root colonization, which was interpreted with care considering some analytical constraints. Results from this experiment give insight into root associations of M. brunneum with cover crops and suggest suitable species for further investigation. Deeper understanding of complex interactions which influence plant-fungus relationships (e.g., competition with other soil microbes or the impact of agricultural practices), could improve the efficiency of corresponding products and facilitate additional applications and benefits (e.g. improved nutrient uptake and disease resistance) by utilizing EPF root associations. KW - Metarhizium brunneum KW - Endophytic fungi Y1 - 2022 ER - TY - THES A1 - Vahrenhorst, Nele Sarah T1 - How to initiate transformative research on permaculture in the Lower Rhine valley? A framework developed based on the analysis of previous experiences N2 - As climate change continues to have negative effects on agriculture, the European Commission calls for sustainable farming approaches as solutions to challenges associated with climate change and therefore propose living labs as a transformative, transdisciplinary and participatory research mode in order to enforce the resilience of farming systems. Permaculture is considered as an approach for the living lab at the Lower Rhine as it aims at integrating sustainable management practices and ethical principles to provide the framework for a holistic approach that could provide an alternative to current management practices and their negative effects on the region. The thesis at hand aims at establishing a living lab framework that allows involvement of regional stakeholders from a range of sectors in a regional network that is part of a trinity of projects that additionally include an on-site test area and a digital knowledge platform. By performing literature research and interviews with regional primary producers and experts of the field, the thesis proceeds to place the permaculture living lab in the currently available context of living lab categorizations and provides a detailed framework with step-by-step instructions to follow as well as a selection of aspects to keep in mind in order to initiate transformative research on permaculture in the form of a living lab in the Lower Rhine region. Apart from the needs of regional primary producers, existing networks and organizations relevant for the living lab are identified, as well as successfully implemented living labs in Zurich, Lisbon, Bern and New York whose objectives align at least partially with those of the future permaculture living lab that can provide experience and suggestions for the planning process. Y1 - 2023 ER - TY - THES A1 - Rümmele, Yvonne T1 - Advantages and disadvantages of mulching in market garden systems N2 - The need for sustainable and resilient food production is constantly increasing. Methods such as cover cropping, the use of mulches and non- or minimal tillage are recommended in large-scale agriculture, yet are not typically found in standard versions of market gardening, as developed by J.M. Fortier. In order to redesign the market gardening system towards more sustainability, the advantages and disadvantages of mulching, possible allelopathic effects from cover crops and mulches, and a possible on-site production of transfer and insitu mulch, were investigated. For this purpose, a literature review was carried out and afterwards a market garden rotation including cover crops was designed. The review results suggested that positive (crop-promoting) as well as negative (crop- and weed-reducing) allelopathy from cover crops exist and are includable into the system as a form of integrated weed management system. It was found that the advantages of mulching outweigh the disadvantages and that it is possible to redesign the market garden system towards more sustainability. KW - Market gardening KW - Allelopathy KW - Intercropping KW - Cover crops KW - Mulch Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-17025 ER - TY - THES A1 - Ziriko, Ponsiano T1 - Provenance influence on African Baobab (Adansonia digitata) mycorrhization potential. N2 - African baobab (Adansonia digitata L.) tree parts are mostly harvested for nourishment and economic purposes. However, the products are only extracted from the wild and are threatened by depletion which necessitates research into the species domestication and cultivation. Mycorrhization involves promoting foreign and native mycorrhiza linkages to improve the roots’ efficiency in nutrients and moisture acquisition. While origin can impact the development of A. digitata, its impact on the species mycorrhization potential is not well understood, and was investigated in this thesis. A. digitata plants were grown from seeds of semi-arid, sub-humid and humid zone origins of Benin inside a controlled climate chamber. The seedlings from each origin received native soil, commercial mycorrhiza fungi (alternative) and control treatments. Growth parameters were determined before treatments application and at termination. Models combining the effects of treatment, zone origin, unique tree characteristics and block arrangement were used for statistics. Only seedlings of the humid zone origin had significantly higher initial leaf count than counterparts from other origins. Insignificant differences among origins and treatments were observed for all the other parameters. Inconsistent significant interaction of treatment and origins was observed for final leaf count, stem diameter, root collar diameter, fresh taproot and dry lateral root weights. The results indicated A. digitata seedlings’ ability to show morphological similarities when grown under uniform conditions irrespective of the genetic variations which might exist among seedlings. These growth trends were not 1 affected by the presence of commercial and native microbes. Inconsistent interaction effects warrant further investigation to ascertain specific individual tree seedlings which might have been significantly impacted by treatments. Y1 - 2025 ER -