Summer Drought Effects on Warm‐Season Turfgrass Canopy Temperatures

Abstract

Little information exists detailing the impact of water restrictions on urban amenity grass systems. Through the use of an automated rainout shelter, a two‐year field study was conducted to evaluate how water restrictions, drought, and warm‐season turfgrass species influence the changes in radiant heat accumulation within warm‐season turfgrass systems. Canopy temperatures and leaf firing characteristics of 3 turfgrass species and 24 total cultivars were monitored through a 60‐day summer drought in San Antonio, TX, in two successive years. Zoysiagrass maintained significantly higher canopy temperatures compared to bermudagrass and St. Augustinegrass. Across species, midday canopy temperatures ranged 1.0 to 49.0°F warmer than maximum daily air temperatures. During the final 30 days without water, midday canopy temperatures averaged 22 to 43°F and 15 to 38°F warmer than maximum daily air temperatures for 2006 and 2007, respectively. Bermudagrass maintained a significantly lower overall leaf firing response and rates of developing leaf firing compared to St. Augustinegrass and zoysiagrass. Results indicate that the benefits of water conservation through a mandated complete water restriction during drought must recognize potential negative impacts of turfgrass systems losing the ability to buffer radiant heat as plants desiccate from low levels of soil moisture.