Seasonal Growth and Nitrogen Uptake of Encore Azalea ‘Chiffon’ Affected by Nitrogen Availability and Containers

Abstract

Additional index words. biocontainer, seasonal growth, Rhododendron Abstract. Plant growth and nitrogen (N) uptake of Encore Ò azalea 'Chiffon' (Rhododendron sp.) grown in a traditional plastic container or a biodegradable container made from recycled paper were investigated over the 2013 growing season. Three hundred twenty 1-year-old azalea liners, grown in two types of containers, were fertilized twice weekly with 250 mL Nfree liquid fertilizer with no N or 15 mM N from ammonium nitrate (NH 4 NO 3 ). Biweekly from 10 May to 3 Dec., five plants from each N rate and container type were selected randomly to measure plant height, widths, and leaf chlorophyll content in terms of soil-plant analysis development (SPAD) readings, and were then harvested destructively for nutrient analyses. Leaf SPAD readings and tissue N concentration were influenced mostly by N rate rather than container type, with 15 mM N producing greater values than the no-N treatment.

Nitrogen Fertigation Rate and Foliar Urea Spray Affect Plant Growth, Nitrogen, and Carbohydrate Compositions of Encore Azalea ‘Chiffon’ Grown in Alternative Containers

“…The superior effects of using the biocontainers became significant later on in the season in September, when there could be a second growth flush (data not shown). This is corroborated by our previous study investigating the seasonal growth and N requirement of the same Encore ® azalea cultivar [32]. Greater PGIs resulted from the use of plastic containers early in the season, whereas the use of biocontainers with higher N rates resulted in higher PGI from mid-September through to plant harvest.…”