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Rapid and standard 3M Petrifilm methods were compared (Aerobic Plate Count for bacteria (AC), Rapid Yeast and Mold (RYM), and E.coli and Total Coliform (Ec/TC)), as well as diluents and incubation times and temperatures. Other methods tested included LaMotte BioPaddles, Biosan SaniCheck YM, ColiTag and AgDia strips to select the ‘best’ method for on-site monitoring. Periodically, samples were submitted for DNA Multiscan analysis for plant pathogens to obtain correlations between this method and the 3M TY&M method being used as an ‘indicator’ test for the presence and level of fungal plant pathogen populations. A 2 year data base of water quality over different production systems, seasons and treatment systems was developed. Grower protocols for sampling and monitoring methods were developed and refined in cooperation with growers and their designated personnel. Training of owner/growers and/or designated personnel was carried out at each participating operation. The in-house data generated was compared to the on-going monitoring program in order to assess the practicality of the methods in-house and get feedback from the individual cooperators.
This project was intended to provide guidance on innovative water treatment technologies for the horticulture sector in Ontario. The scope of the project included: installation of 2 portable hybrid treatment systems (HTS) to test the operational parameters needed to treat (i.e. clean) floriculture greenhouse and nursery wastewater so that it can be either safely discharged to the environment, or rendered suitable for re-use within the operation, installation of 2 permanent hybrid treatment systems (HTS), one at a container nursery and one at a flower greenhouse, using information obtained from the pilot systems as well as previous studies, and development of a Guidance Document for growers to help them make informed decisions regarding water management and treatment options. The Hybrid Treatment System represents a flexible tool for water treatment, particularly in situations where there is a desire to recirculate or discharge very clean water. Removal rates in each of the selected media are dependent on temperature, flow rate (hydraulic retention time), and nutrient concentration. Temperature is particularly important for the woodchip cells, since these are primarily a biological treatment. For optimum performance these systems need to be designed on the basis of projected daily water volumes, concentrations for treatment, and expected temperatures over the entire production period. While these systems do require a significant footprint outdoors, they can be tailored to match the volumes and fluctuations of a particular operation. And in many cases, the surface of the treatment can be used as a production area, but machine traffic should be avoided. It is highly recommended that growers conduct a self-assessment of the farm prior to choosing a water management solution.
Four dehumidification technologies were tested at three different facilities over a three year period: commercial mechanical refrigeration dehumidifier (MRD), chemical liquid desiccant dehumidifier (LDD), air-to-air heat recovery ventilation system (HRV), and finally a prototype called energy recovery ventilation (ERV), which is a combination of liquid desiccant approach (wet mode) and an air-to-air heat exchanger (dry mode). Overall, energy savings could be achieved, but the dehumidification systems controls needed. to be strategically integrated in the greenhouse computer control system logic in a manner that resulted in optimal performance in order for the savings to be significant. A method for in-house qir quality monitoring was developed using 3M Petrifilms, and showed a linear correlation with standard air quality testing methods.
The project assessed the potential environmental impacts of land application of Greenhouse nutrient feedwater (GNF) under the Ontario Nutrient Management Act as a best management practice (BMP) through field infiltration experiments established at four greenhouse operations representing a cross section of the vegetable greenhouse sector near Leamington, Ontario. The results demonstrated that the majority of the nutrients and other dissolved constituents in GNF applied at the highest permissible rates and practical loadings over a variety of soil types and agricultural land use practices remained within the vadose zone and at low concentrations over the course of the monitoring period. No evidence of significant environmental impact from the land application of GNF was observed. Overall, the results of the study suggest that land application of GNF in accordance with Ontario’s regulations is a feasible and environmentally reasonable treatment option for managing GNF.
En lutte biologique en serre, l’utilisation des sachets à libération lente d’acariens prédateurs que l’on accroche sur les végétaux est de plus en plus répandue en production horticole ornementale. Un des objectifs de ce projet était d’évaluer le taux de libération de 2 types d’acariens prédateurs provenant de sachets à libération lente. Un deuxième objectif consistait à évaluer l’efficacité de deux méthodes de décompte des prédateurs sortant des sachets. Le taux de libération des acariens prédateurs fournira aux producteurs une façon d’évaluer la qualité du contenu du sachet tandis que la méthode de décompte la plus efficace leur permettra de savoir si les sachets performent comme prévu.
L’humidité relative élevée dans les serres peut causer une augmentation de la consommation énergétique (déshumidification par ventilation naturelle ou forcée) ainsi que des problèmes fongiques comme le botrytis (tomate, basilic, ornemental) et le mildiou (basilic, impatiens), ce qui cause une utilisation accrue des fongicides et des pertes de production chez les producteurs. Une évaluation du potentiel d’utilisation de la technologie VLHC (Ventilate Latent Heat Converter) de la compagnie AGAM pour déshumidifier les serres a donc été réalisée. Aussi pour informer le secteur des enjeux reliés à la gestion de l’humidité et des défis rencontrés lors de l’expérimentation, la création d’un outil de réflexion sur ce thème a été réalisé. Le but de celui-ci est de présenter les questionnements et les actions pour régler les problèmes engendrés par une gestion déficiente de l’humidité.
A comprehensive survey of plant pathogen populations (measured by DNA Multiscans) in irrigation water leachate and/or runoff from the range of Ontario flower and vegetable greenhouses and container nurseries was conducted to help assess the level of risk involved in operations switching to recirculating systems. The ability of several bioremediation technologies to remove plant pathogens from recycled irrigation water (e.g. constructed wetlands, woodchip biofilters) was evaluated as well as the effectiveness of current plant pathogen disinfection systems.
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