Physiological response of two turfgrass species to increasing drought and salinity stress using a line source gradient

Dorothy E Dean, University of Nevada, Las Vegas


A line source gradient study was initiated to investigate the feasibility of using the saline aquifer, existing beneath the Las Vegas valley, as an alternative irrigation source for turfgrass. Results indicated that the aquifer could be used as a supplemental irrigation source, without any diminished turfgrass quality, if total water potentials {dollar}\rm(\Psi\sb{T}){dollar} were maintained above species specific thresholds, where {dollar}\rm\Psi\sb{T}{dollar} is defined as the sum of the matric {dollar}\rm(\Psi\sb{M}){dollar} and osmotic {dollar}\rm(\Psi\sb{\Pi}){dollar} potentials. The soil water potential components {dollar}\rm(\Psi\sb{M},\Psi\sb{\Pi}){dollar} were found to additively affect yield, evapotranspiration, turf color, percent cover, and turf temperature. Leaf xylem water potential, stomatal conductance, and tissue osmolality responded to the interactive effects of {dollar}\rm\Psi\sb{M}{dollar} and {dollar}\rm\Psi\sb{\Pi}.{dollar} Water use efficiency decreased with increasing salinity in tall fescue but not in bermudagrass. Tissue ion concentrations remained unchanged with increasing {dollar}\rm\Psi\sb{T}{dollar} in bermudagrass, while all ion concentrations in tall fescue, except K, increased with increasing {dollar}\Psi\sb{\Pi}{dollar} and {dollar}\rm\Psi\sb{T}.{dollar}.