580 Pflanzen (Botanik)
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Water retention properties of wood fiber based growing media and their impact on irrigation strategy
(2024)
Distribution of water and air in growing media during ebb-and-flow irrigation depends on water storage properties (water retention curve) and water transport properties (hydraulic conductivity) of the materials. Growing media with their high number of coarse pores are known to exhibit strong hysteresis, i.e., differences in the water retention properties during drying and wetting cycles. To account for potential ecological disadvantages of peat, wood fibers are commonly used as substitutes for peat in growing media. However, the wood fibers generally have higher air capacities and hydraulic conductivities and lower water capacities compared to peat which may results in necessary adaptions of the irrigation strategy. Tools to optimize irrigation systems are physically based water transport models, such as HYDRUS-1D, which is commonly used to describe water transport in soils, but not often for growing media. In this study, white peat and pure wood fibers were used to describe differences in their water retention behavior. Water retention curves (drying cycles) and hydraulic conductivities were measured with standard analytical procedures. Hysteresis of the water retention curves was analytically determined based on their capillary rise properties. The results were used with a modified HYDRUS-1D model to test model quality against measured water contents during ebb-and-flow irrigation cycles and to optimize the irrigation strategy for the different materials. The results showed that the model quality was sufficiently good only if the strong hysteresis of the water retention curves was considered during the simulation process. Different strategies were tested to modify ebb-and-flow irrigation (irrigation frequency, irrigation duration and irrigation height) in that way that the water suction in the root zone was similar to that of the peat material. Simulation results showed that significant improvements could only be reached by increasing the flooding depth in ebb-and-flow systems to ensure an optimum water supply of plants in the wood fiber based growing media.
Test von Schnellverfahren zur Bestimmung der Benetzungseigenschaften von Kultursubstraten (Abstract)
(2024)
Evaporation from growing media significantly contributes to increasing the humidity in greenhouses. The effects of a pine bark mulch cover on substrate evaporation was evaluated with different pot experiments. The obtained data have been tested within the water balance model HYDRUS-1D, which was originally developed for mineral soils. Objective of this study was to test the performance of HYDRUS-1D to describe evaporation in plant containers and to evaluate the effect of pine bark as cover layer or layers within growing media. Application of pine bark in combination with peat substrate reduced evaporation up to 50% depending on position, thickness of mulch layer and water content of the substrate. The highest reduction in evaporation was measured in a dry substrate which is covered with 4 cm pine bark. The HYDRUS-1D model describes evaporation from growing media in combination with layers of pine bark correctly as long as hysteresis of the water retention curve and vapor flow is considered in the model.
GIS-gestützte Zustandserfassung von Befahrungslinien in einem Landesforst und einem Privatwald
(2013)
In einem niedersächsischen Forstgebiet ist die räumliche Anordnung und das Erscheinungsbild von Befahrungslinien (Rückegassen)mittels GPS erfasst worden. Anhand der Fahrspurtiefe wurde beurteilt, in welchem Umfang potentielle Bodenschäden innerhalb der Befahrungslinien auftreten und ob es diesbezüglich Unterschiede zwischen der Bewirtschaftung eines Landesforstes und eines Privatwaldes gibt. Zusätzlich wurden Parameter der spontanen Vegetation sowie das Vorhandensein von Fremdstoffen erhoben. Die Erfassung ergab einen geringeren Flächenverbrauch durch Befahrungslinien im Landesforst gegenüber dem Privatwald. Die Spuren im Landesforst wiesen jedoch einen höheren Anteil an Fahrspurtiefen ? 15 cm auf. Die aufgenommenen Vegetationsdaten der Gassen ergaben unter anderem ein verstärktes Vorkommen von Juncus effusus als Zeigerpflanze von nassen und verdichteten Böden. Fremdstoffe kamen ausschließlich im Privatwald vor.
Zierpflanzen termingerecht und den Qualitätsansprüchen entsprechend produzieren
Eine termin- und qualitätsgerechte Zierpflanzenproduktion setzt solides Wissen über die Pflanzenansprüche voraus. Dargestellt werden
- Wirkungen der Wachstumsfaktoren,
- Steuerungsmöglichkeiten bei verschiedenen Kulturabschnitten,
- Aufbereitung der Produkte,
- Beispiele für Produktionsmethoden marktrelevanter Topfpflanzen und Schnittblumen.
Die Produktion von Topfpflanzen umfasst die Kultur von Beet- und Balkonpflanzen, Topfstauden und Zimmerpflanzen. Die Datensammlung enthält Produktionsverfahren, welche anhand produktionstechnischer, arbeits- und betriebswirtschaftlicher Kennzahlen beschrieben sind. Unter www.ktbl.de gibt es eine kostenfreie Excel-Anwendung für betriebsindividuelle Berechnungen.