Growth and Quality Response of Four Container-grown Nursery Crop Species to Low-phosphorus Controlled-release Fertilizer

The amount of phosphorus (P) conventionally recommended and applied to container nursery crops commonly exceeds plant requirements, resulting in unused P leaching from containers potentially contributing surface water impairment. An experiment was replicated the Middle Atlantic Coastal Plain (MACP) Ridge Valley ecoregions Virginia compare effect a low-P controlled-release fertilizer (CRF, 0.9% or 1.4% depending on species) vs. conventional CRF formulation (control, 1.7% P) shoot growth, crop quality, substrate nutrient concentrations four species: ‘Natchez’ crape myrtle ( Lagerstroemia indica × fauriei ), ‘Roblec’ Encore azalea Rhododendron hybrid), ‘Radrazz’ Knock Out rose Rosa ‘Green Giant’ arborvitae Thuja plicata standishii ). In both ecoregions, resulted 9% 26% lower dry weight all species compared with those given formulation, but quality ratings for two economically important species, arborvitae, were similar between treatments. When fertilized CRF, MACP ecoregion had ∼56% 75% pore-water than that received control CRF. Nitrate-nitrogen (N) pore at week 5 more six times greater control-fertilized plants which may have been result urea-N content heterogeneous nature CRFs. Lower water-extractable N indicate less environmental risk increased efficiency. Our results suggest CRFs can be used produce certain ornamental successfully without sacrificing quality; however, early adopters will need evaluate specific before implementing large scale.