Reduced creeping bentgrass fairway reflectance following synthetic colorant application

Abstract

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

Volatilization or Recovery of Fairway Foliar Nitrogen Fertilizer via Time and Spray Oil Inclusion

“…Previously reported data were used to support this study and are available at doi:10.5061/dryad.cc2fqz67d. These prior datasets are relevantly cited within the text as references [47,48]. Remaining canopy dark green color index (DGCI), N offtake, and fertilizer N recovery data supporting the findings of this study are available from the corresponding author upon request.…”

“…While perhaps underwhelming relative to published and more comprehensive percent FNR values [20,31]; the N rate adjustment for the N in Civitas makes the pooled main effect percent FNR means (Table 1) the more appropriate inference tool for comparing treatments. The concomitant 0.232 kg ha -1 N load from Civitas comprised only a fraction of the FNR LSD 0.05 at 416 and 435 DFI, conferring a linear model of increased fairway bentgrass clipping yield by cumulative Civitas treatment over the two growing seasons [47] but contrasting the detrimental effects reported in the second year of repeated applications to putting greens in the field [14][15][16][17].…”