Die chronologische Liste zeigt aktuelle Veröffentlichungen aus dem Forschungsbetrieb der Hochschule Weihenstephan-Triesdorf. Zuständig ist das Zentrum für Forschung und Wissenstransfer (ZFW).
Amendment of growing media with Chabazite, a natural zeolite with a high ammonium sorption capacity, in combination with ammonium fertilization might be a promising approach to reduce nitrogen leaching in container nurseries. However, it is unclear if ammonium, which is adsorbed to Chabazite is still plant-available. Thus, a pot trial with Photinia fraseri was conducted with growing media containing 25 vol % of either pumice or Chabazite. Chabazite firstly was used as received and secondly was charged with two levels of ammonium resulting in nitrogen loads of 1 and 5 g N pot‑1, respectively. The untreated Chabazite was fertilized with 1 g N pot‑1 as ammonium sulfate divided in repeated applications in accordance with the control (pumice). In these two treatments plant growth and nitrogen uptake was more or less the same. Plants in the growing media with NH4-charged Chabazite receiving also 1 g N pot‑1 produced a significantly lower fresh mass compared to the untreated Chabazite and pumice and suffered from slight nitrogen deficiency. If 5 g N pot‑1 were applied with charged Chabazite, plants grew better and took up more nitrogen. The results indicate that Chabazite did not influence negatively plant availability of fertilized ammonium. However, ammonium from charged Chabazite is only partly plant-available. With increasing NH4 charging of Chabazite, ammonium and nitrate accumulated in the growing media.
The value chain of flowering potted plants (FPP) is associated with environmental, social and economic sus-tainability challenges. Indicator-based assessment methods can provide insights into sustainability performanceof agricultural value chains. The FPP value chain is not comparable to other agricultural systems and thereforecannot be assessed with existing indicator-based tools. In this study, a framework was developed for sustain-ability assessment of the FPP value chain, from breeding to distribution. The development of the frameworkinvolved defining sustainability themes and subthemes based on the characterization of the value chain and theinvestigation of social, environmental and economic sustainability challenges. The generic sustainabilityassessment tools, Sustainability Assessment of Food and Agriculture Systems (SAFA) and Response-InducingSustainability Evaluation (RISE), provided the foundation for indicator selection and development. The cur-rent study emphasized the need for a system-specific view, especially in unique systems such as the FPP valuechain, because generic assessment tools, such as SAFA and RISE, do not cover all sustainability subthemes. Mostof the indicators missing from generic assessment tools were environmental indicators. Environmental assess-ment is closely related to value chain stages and product-specific processes, therefore indicators were allocatedaccording to the value chain stages, breeding, production and distribution. Social sustainability themes areinfluenced by national and regional socio-economic conditions, such as government provision of healthcare and asocial safety net. Therefore, indicators are allocated based on geographical regions and stakeholder groups. Theeconomic subthemes are determined by industry structure and sector-specific conditions. The ornamental sectoris characterized by low margins and high uncertainty, related to profitability and vulnerability. Despite the initialevaluation performed in the current study, in the next step, industry actors need to determine the feasibility ofthe indicators. The implementation of the framework developed in the current study will provide further insightsinto the value chain, which will guide actors in taking actions for performance improvement and provideguidance for policy-makers in setting sustainability targets.
Mehr
Prof. Dr. Bernd Hertle
Die Weihenstephaner Gärten (2021) Gesellschaft der Staudenfreunde. Tübingen-Kusterdingen. 6.11.2021 .
Dipl.-Biol. Daniel Hauck,
Dr. Dieter Lohr,
Prof. Dr. Elke Meinken,
Urs Schmidhalter
BackgroundUsing secondary phosphorus (P) sources recovered from waste streams for base fertilization of soilless growing media may help conserve the global phosphate resources. However, little is known regarding the plant availability of P from secondary sources for soilless plant production.AimThe objective of this study was to investigate the plant availability of P from secondary sources using a peat-based growing medium and standard extraction methods.MethodsSeventeen secondary P sources differing in terms of feedstock and processing were tested, and their fertilization efficacy was compared with that of water-soluble monocalcium phosphate (MCP-P) in a pot experiment using marigolds. The correlation of plant P uptake with calcium chloride + diethylenetriaminepentaacetate (CAT) and/or calcium–acetate–lactate (CAL) extractable P amount in the growing medium (PCAT and PCAL, respectively) was examined.ResultsOnly three of the 17 tested secondary P sources (all struvite forms) exhibited comparable fertilization efficacy to MCP-P. The remaining sources showed P uptake varying between 4% and 91% of MCP-P. For precipitates from liquid waste streams and untreated organic waste, except for sewage sludge and compost, the P uptake ranged from 71% to 100%. The highest variability (4%–86%) was observed for thermally and thermochemically treated secondary P sources. Plant P uptake was closely correlated with PCAT (R2 = 0.76) and PCAL (R2 = 0.78), and this correlation became even stronger when PCAT and PCAL were combined (R2 = 0.89).ConclusionsMost struvite forms meet the requirements of base P fertilization for soilless plant production and can substitute water-soluble fertilizers obtained from primary P sources. The combination of PCAT and PCAL may be a promising approach to characterize the plant availability of P from secondary sources in soilless growing media and warrants further consideration.
Wir verwenden Cookies. Einige sind notwendig für die Funktion der Webseite, andere helfen uns, die Webseite zu verbessern. Um unseren eigenen Ansprüchen beim Datenschutz gerecht zu werden, erfassen wir lediglich anonymisierte Nutzerdaten mit „Matomo“. Um unser Internetangebot für Sie ansprechender zu gestalten, binden wir außerdem externe Inhalte unserer Social-Media-Kanäle ein.
