Die chronologische Liste zeigt aktuelle Veröffentlichungen aus dem Forschungsbetrieb der Hochschule Weihenstephan-Triesdorf. Zuständig ist das Zentrum für Forschung und Wissenstransfer (ZFW).
Regulated deficit irrigation (RDI) comprises controlled reduction of irrigation during certain phases of plant development, accepting minor yield reduction but maximising net returns. To optimise RDI, plant response-based irrigation scheduling may be essential. For this, the knowledge of plant reactions to soil water regimes is indispensable. In field trials (randomized block design, 3 repetitions), ‘Nanthya’ carrots (F1-hybrid) were grown at 20, 40, 60 and 80% field capacity (determined by TDR sensors), yielding soil water contents of 5.1±0.2, 6.2±0.8, 10.1±0.5 and 11.2±0.2% (controls). To guarantee constant controlled soil water contents, plastic rain shelter (76% transparency) were applied. Plots were irrigated if necessary. Treatments started 23 d after sowing (DAS), first sampling was 91 DAS, while final harvest was 106 DAS. On each date, fresh and dry mass, water content, water potential, osmotic potential, turgor and stiffness of carrot tubers were analyzed. Root fresh mass (n=20 carrots per treatment) was higher at high water availability only at the 1st sampling but not at the final harvest. Here, water regime did not affect yield. At this time, root tuber water potential was lower than at the 1st sampling and it was also lower at low soil water availability (20%, 40%). Similar results were obtained for the mean osmotic potential. These variations partially resulted from osmotic adjustment (at 1st harvest) and from a lower root tuber water content at the final sampling. The generally higher modulus of elasticity at this date indicated water volume-independent cell wall-stiffening, i.e. elastic adjustment. The presented results point out that moderately reduced (by 20%) irrigation of carrots does not affect their yield, while pronounced water shortage may induce physiological adjustment.
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Ivonne Jüttner,
Dr. Petra Liedl,
Prof. Dr. Heike Susanne Mempel
Several lighting strategies in an indoor farm are compared regarding the annual electrical energy consumption. Based on measurements of the energy consumption during one experiment, conducted inside the indoor farm at the HSWT, an energy balancing model was calibrated and subsequently validated by a second experiment. The model was then used to calculate the potential reduction of the annual electrical energy consumption concerning several different lighting strategies. Furthermore, different settings of temperature set points and the impact of an optimized heat transfer coefficient as well as a more efficient performance for heating and cooling are considered. The measured and the modeled energy consumption and the values regained by the model showed a high regression coefficient (R2=0.936). The prediction of the energy consumption during the second experiment was also possible (R2=0.738) with a total difference to the measured consumption of 29.1 kWh. Regarding the given technical settings of the indoor farm, the annual electrical energy consumption can be reduced by up to 16% by an adjustment of the temperature strategy while reaching a similar yield. By assuming an optimized technical setting, the relevance of the lighting strategy increased significantly. Based upon this an annual reduction of the electrical energy consumption of up to 21% seemed conceivable.
Erdbeeren und Paprikas müssen nicht unbedingt tausende Kilometer in unsere Supermärkte reisen. Mit modernen Indoor-Farmen können sie direkt vor Ort angebaut werden.
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.
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Betreuung der Publikationsseiten
Gerhard Radlmayr
Referent für Wissenstransfer und Forschungskommunikation
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