Foliar fertilization–induced injury and recovery of a creeping bentgrass putting green

Two independent trials were conducted on a creeping bentgrass (Agrostis stolonifera L.) putting green (PG) to evaluate early-response of canopy quality, growth, and nutrient use to rate and/or type of foliarly-applied nitrogen (N) fertilizer. Treatments were prepared using soluble ‘Amine’ or ‘Salt’ 15N–0 phosphorus (P)–5.8potassium (K) fertilizer and applied N at 0, 24.5, 37, or 49 kg ha⁻¹. Clipping yields were weighed and digested for N content. Normalized differential vegetative (NDVI) and dark green color (DGCI) indices were determined by canopy reflectance. Relative to the Salt fertilizer, the Amine supported greater mean growth and N offtake rates and higher mean NDVI and DGCI. Two and five days after treatment (DAT), salt-fertilizer treated plots showed lesser canopy quality relative to Amine. These differences increased with N rate, likely due to the greater solute concentration of the Salt fertilizer. Eight to 21 DAT, fewer differences were observed by fertilizer type or rate.