Optimizing Manganese and Iron Delivery in Contrasting Cultivars of Subirrigated Greenhouse-grown Pot Chrysanthemums

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Donetz, Alyna Jane
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University of Guelph

Excessive fertilizer use in greenhouse floricultural operations results in low nutrient use efficiency by plants and poses environmental risk. Here, I tested the hypothesis that usage of fertilizer manganese and iron by modern cultivars of subirrigated pot chrysanthemums can be optimized, while generating plants of similar yield and quality. Moderate levels of manganese and iron were provided during vegetative growth, compared to industry standards, and all nutrients were removed during reproductive growth. Two experiments were conducted for each nutrient in a research greenhouse using a split-plot design with four blocks arranged randomly. Manganese (5.00 −0.3125 µmol L-1) or iron (10.56−0.66 µmol L-1) in an otherwise balanced nutrient solution treatment was the main plot and cultivar was the sub-plot. Nutrient composition of a diagnostic leaf, and the morphology and development of the plants/flowers were essentially unaffected by micronutrient treatment. This novel delivery practice could contribute to the low-input sustainable production of floricultural crops.

chrysanthemum, floriculture, ornamental horticulture, nutrient use efficiency, micronutrient delivery, subirrigation, fertilizer recommendation, iron, manganese, nutrient management