Improving nitrogen and phosphorus use efficiency of potted chrysanthemums grown in a subirrigation system

Regardless of the irrigation system used in greenhouse floricultural operations, nutrient delivery should be optimized so that a lower level of fertilizer is used over the crop cycle, thereby minimizing fertilizer costs and environmental impacts. This novel and innovative approach calls for a constant lower level of nutrients to be delivered during vegetative growth only, and this lower level was optimized so that reproductive growth was primarily sustained by the mobilization of previously-acquired nutrients, rather than current supply from the root system.

Plant height control through nutrition management practices

There is a commonly held belief that high nitrate ratios produce smaller plants and high ammonium ratios produce larger plants. Research into the effect of nutrient ratios on plant height has shown this is not the case. Results of this research have provided recommendations on the practicality of plant nutrient management in limiting bedding plant height.

Reducing water applications

Water application technologies were examined and a thorough literature review which identified some promising irrigation technologies for ornamental nursery plant production purposes. One technology in particular, a sensor-based automated irrigation system, was evaluated in a commercial nursery for pot-in-pot tree production and demonstrated that growers could cut their water usage by more than 50%.

Pathogen suppression in substrates

Suppressing pathogens in the greenhouse setting was the focus of this study. Dr. Zheng selected composted and non-composted organic materials with potential pathogen suppression properties and mixed these materials with other components to form a variety of growing substrates. Pathogenprone ornamental plants such as begonia were then subjected to selected growing substrates. Substrates containing vermicasting or pine bark showed disease suppression, however results were not consistent.

Water treatment technologies

A literature review was conducted and interviews with growers and water treatment companies to assemble information on available technologies. An interactive website will provide growers with an on-line decision process for choosing appropriate technology for their own operation.

Alternative weed control methods and bioherbicides in turf and nursery production

Field trials were conducted on a number of alternative weed control products and it was found that there is significant variation between the claims of manufacturers and actual product performance. Over seeding with some grass species can lead to increased turf cover and is proving to be a favourable option in light of increasing restrictions on pesticide use. This research has delivered a set of clear recommendations for saving money and increasing the efficiency of controlling weeds in turf without conventional herbicides.