Monday, November 5, 2007
75-14

Response of Twenty-Five Warm Season Turfgrasses to Sixty-Day Drought: Late Season and Next Spring Recovery.

David Chalmers1, Kurt Steinke1, Richard H. White1, James Thomas1, and Guy Fipps2. (1) Soil and Crop Sciences, Texas A&M University, 2474 TAMU, College Station, TX 77843, (2) Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843-2474

Parameters established in this research were guided by the City of San Antonio Water System Conservation Program's ordinance to reconsider turfgrass species and cultivars allowed for new home construction. As such, turfgrasses were evaluated for 1) ability to survive a 60-day drought from May through September, and 2) drought tolerance, judged by the extent the grasses recovered when irrigated for a 60-day period following the drought. Twenty-five turfgrass cultivars (8 bermudagrass, 7 St. Augustinegrass, 9 zoysiagrass and 1 buffalograss) grown in four replications, on restricted (10.2 cm) and unrestricted (43+ cm) soil depths, were evaluated for recovery following a 60-day summer drought in 2006. Grasses were sodded in September 2005 for the imposed July 23 to September 20, 2006 drought. Drought was maintained by a 5,000 sq. ft. “drought simulator” (rain-out shelter) which covered plot area during times of rainfall to maintain the 60-day drought period. While the experimental protocol was straightforward, data interpretation was complicated by issues including drought dormancy of some cultivars, chilling temperatures and self limiting leaf canopies that may have inhibited their recovery during the 60-day recovery period. No grasses recovered on the restricted soil depth while all grasses recovered on the unrestricted soil. Recovery after the 60-day irrigated recovery period ranged from 4.3 to 100%. Turf uniformity within each plot at the end of the 60-day recovery was evaluated as a reference for potential for additional recovery during Spring 2007. Recovery after 60-days in autumn will be compared to recovery through June 2007.