Reduced creeping bentgrass fairway reflectance following synthetic colorant application

Repeated measures using multispectral radiometry resolutely quantify canopy attributes of identical turfgrass cultivars under similar management. Concern regarding radiometric characterization canopies <24 h following synthetic phthalocyanine colorant application has been affirmed and is accordingly now avoided; yet explicit guidance on subsequent employ, at time(s) > 24-h postapplication, lacking. Our objective assessed how petroleum-derived spray oil (PDSO) Cu II (CPC) combination product influences creeping bentgrass (Agrostis stolonifera L.) reflectance up to 10 d application. A maintained fairway received semimonthly 9.76 kg ha–1 soluble N treatments alone or in with 27 L PDSO+CPC ha–1. Treatment by increased mean shoot growth (kg ha–1) dark green color index (DGCI) calculated visible waveband reflectance. Yet reduced far red near infrared from treated plots artificially deflated normalized differential vegetative indices. Cautious interpretation indices relying 710-to-810-nm encouraged when evaluating fairways PDSO product(s).