Browsing by Person "Zikeli, Sabine"

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Agrivoltaics mitigate drought effects in winter wheat
(2023) Pataczek, Lisa; Weselek, Axel; Bauerle, Andrea; Högy, Petra; Lewandowski, Iris; Zikeli, Sabine; Schweiger, Andreas
Climate change is expected to decrease water availability in many agricultural production areas around the globe. At the same time renewable energy concepts such as agrivoltaics (AV) are necessary to manage the energy transition. Several studies showed that evapotranspiration can be reduced in AV systems, resulting in increased water availability for crops. However, effects on crop performance and productivity remain unclear to date. Carbon‐13 isotopic composition (δ13C and discrimination against carbon‐13) can be used as a proxy for the effects of water availability on plant performance, integrating crop responses over the entire growing season. The aim of this study was to assess these effects via carbon isotopic composition in grains, as well as grain yield of winter wheat in an AV system in southwest Germany. Crops were cultivated over four seasons from 2016–2020 in the AV system and on an unshaded adjacent reference (REF) site. Across all seasons, average grain yield did not significantly differ between AV and REF (4.7 vs 5.2 t ha−1), with higher interannual yield stability in the AV system. However, δ13C as well as carbon‐13 isotope discrimination differed significantly across the seasons by 1‰ (AV: −29.0‰ vs REF: −28.0‰ and AV: 21.6‰ vs REF: 20.6‰) between the AV system and the REF site. These drought mitigation effects as indicated by the results of this study will become crucial for the resilience of agricultural production in the near future when drought events will become significantly more frequent and severe.
Comparison of soil phosphorus extraction methods regarding their suitability for organic farming systems
(2023) Wanke, Daniel J.; Heichel, Jasmin; Zikeli, Sabine; Müller, Torsten; Hartmann, Tobias Edward
Background: Organic farmers frequently report sufficient yield levels despite low or even very low soil phosphorous (P) contents questioning the applicability of widely used laboratory methods for soil P testing for organic farming. Aims: The aim of this study was to compare the validity of a broad range of different soil extraction methods on soils under organic management from South West Germany and to test the correlation of the measured soil P concentration with plant offtake. Methods: Twenty-two soil samples of eight different organic farms were extracted with different solutions: (1) water, (2) CAL, (3) Olsen, (4) Mehlich 3, (5) Bray P1, (6) Bray P2, (7) NaOH+Na2EDTA, and (8) total P. The results were then correlated with above ground plant P. Results: Spearman's rank correlation coefficient (rs) of correlations between above ground plant P and extractable soil P (Water-P, CAL-P, and Olsen-P [+active charcoal {+AC}]) determined with ICP-OES were strong (0.94, 0.90, and 0.93, respectively). Among the tested methods, above ground plant P showed a strong correlation with CAL-P as detected by ICP-OES (rs = 0.90) and colorimetry (rs = 0.91). The comparison of CAL-P data provided by farmers and CAL-P analyzed during this research showed discrepancies between the results. Conclusions: The results of this study indicate that the CAL method can be used in organic farming despite a low extraction of organic P (Porg). Furthermore, it is recommended for farmers to take soil samples for analyses regularly and interpret changes in P in the long-term instead of interpreting individual samples.
The effects of leguminous living mulch intercropping and its growth management on organic cabbage yield and biological nitrogen fixation
(2022) Stein, Sophie; Hartung, Jens; Möller, Kurt; Zikeli, Sabine
In organic horticulture, living mulches (LM) are used for weed suppression and erosion prevention. In addition, leguminous LM can contribute to higher nitrogen (N) import into vegetable cultivation systems via biological N2 fixation (BNF). In order to investigate the effect of LM systems, a two- as well as three-year field experiment was conducted between 2019 and 2021 at two locations in Southwest Germany. White cabbage was intercropped with two different clover varieties (Trifolium repens cv. ‘Rivendel’, with regular growth and T. repens cv. ‘Pipolina’, a micro clover) and perennial ryegrass (Lolium perenne cv. ‘Premium’). Bare soil (with spontaneous vegetation) without intercropping was the control treatment. The second factor was the growth management of the LM: incorporation by rototilling before planting the cabbage, intercropping with the cabbage and no LM growth management, and intercropping with mulching of the LM during the cabbage growing. The results show that rototilling LM before planting the cabbage did not lead to higher weight of cabbage residues or differences in total head yield among the treatments for growth management. Intercropping without further LM growth management did not result in a reduced total head yield of cabbage compared to mulching. The micro clover ‘Pipolina’ showed no reduced competition with cabbage compared to the regular-growing white clover ‘Rivendel’. Therefore, we conclude that leguminous LM systems, regardless of growth management, can achieve high yields with sufficient irrigation and additional fertilization while increasing the inputs of N via BNF into the entire cropping system.
Status-Quo und Perspektiven von Zweinutzungshühnern in Baden-Württemberg : Ergebnisse eines World-Cafés im Rahmen des 1. Dialogforums des Projektes „ZweiWert“ am 2.3.2023.
(2023) Bermejo, Gabriela; Imort-Just, Annik; Gebhardt, Beate; Hess, Sebastian; Kiefer, Lukas; Zikeli, Sabine
The motivation behind the growing interest in dual-purpose chicken is diverse. Among other things, it is driven by the prohibition of killing male chicks from laying lines, by the desire to improve animal welfare in general, and by the preservation of genetic biodiversity and a more sustainable poultry production system. The project "ZweiWert" aims to create a regional network of actors in order to build up a value chain for dual-purpose chickens in Baden-Württemberg. Following a status quo and potential analysis of the agricultural production of dual-purpose chicken, a network will be established along the entire value chain, so that a sustainable production as well as a regular supply of the resulting products can be ensured. In order to promote the exchange between actors and to be able to develop policy options and recommendations, dialogue forums will be organized during the course of the project. The first forum took place in March 2023 and brought together representatives from different sectors. After various expert contributions, participants were able to exchange views on different areas of the value chain in the format of a World Café. In particular, the topics of networking and economic efficiency, cooperation, aspects of the legal/political framework and the need for more transparency and communication were mentioned during these discussions.
Zweinutzungshuhn – was ist das? Umfrage unter Landwirt*innen und Geflügelhalter*innen in Deutschland 2022
(2023) Gebhardt, Beate; Bermejo, Gabriela; Imort-Just, Annik; Kiefer, Lukas; Zikeli, Sabine; Hess, Sebastian
To comply with the ban on chick culling that has been in effect since January 2022, the Federal Ministry of Food and Agriculture proposes three alternatives, including the hatching of dual-purpose chickens. In addition to the breeding and economic challenges of establishing dual-purpose animals in the value chain, the inconsistent understanding of what a dual-purpose chicken actually is and how its characteristics can be successfully communicated to consumers are seen as challenges. The goal of this working report is to present what a dual-purpose chicken is and what understanding farmers have of it. The German nationwide online survey among farmers and poultry farmers regarding the understanding and future of dual-purpose chickens was conducted in autumn 2022 as part of the EIP-Agri project "ZweiWert." The EIP project titled "Building Value Chains for Dual-Purpose Chickens in Baden-Württemberg" (ZweiWert) is funded by the Ministry of Food, Rural Areas and Consumer Protection of Baden-Württemberg from 01/2022 to 12/2024. Project partners include the Naturland Association of Baden-Württemberg, several departments of the University of Hohenheim, and many partners from agricultural production and marketing.