Effects of Drought and Traffic Stresses on Physiological Responses and Water Use Characteristics of Creeping Bentgrass (Agrostis stolonifera) and Annual Bluegrass (Poa annua).

Creeping bentgrass and annual bluegrass are two important putting green species in the golf industry that are both sensitive to drought and traffic stress. The goal of this field study was to investigate the physiological responses of creeping bentgrass and annual bluegrass under different volumetric soil moisture contents as well as different levels of traffic to detect significant differences in water use characteristics, rooting, and hormone production. Ethylene is a growth inhibiting and senescence stimulating hormone, by measuring the evolution of ethylene in both turfgrass species, we will gain a better understanding of how to manage annual bluegrass and creeping bentgrass putting greens. Plots were evaluated to investigate turf responses to irrigation set to be maintained at three different levels (16%, 12%, and 8% WFV) and traffic stresses (none, low traffic and moderate traffic) on a USGA constructed putting green. The effect of irrigation and traffic treatments to both creeping bentgrass and annual bluegrass was measured. Creeping bentgrass under irrigation and traffic treatments maintained better soil moisture content, chlorophyll content, visual turf quality, canopy reflectance and photochemical efficiency as well as maintained longer roots and higher rootmass when compared to annual bluegrass. Overall annual bluegrass requires more water to maintain soil moisture at the target irrigation levels when compared to creeping bentgrass. Annual bluegrass also appeared to have higher ethylene production when it is compared to that of creeping bentgrass. The results from this study suggest that creeping bentgrass maintains better water use characteristics and tolerance to traffic when it is being compared to annual bluegrass, while annual bluegrass exhibits higher ethylene production.