Response of Six Bermudagrass Cultivars to Different Irrigation Intervals

A 2-year greenhouse study was conducted at Clemson University, Clemson, S.C., in 2003 and 2004 to determine drought responses of six bermudagrass (Cynodon spp.) cultivars at four irrigation intervals. Cultivars selected from the 2002 National Turfgrass Evaluation Program Bermudagrass Trial were ‘SWI-1012’, ‘Arizona Common’, ‘Tift No.3’, ‘Tifsport’, ‘Aussie Green’, and ‘Celebration’. Treatments included 5-, 10-, and 15-day irrigation intervals plus a control (irrigated daily). Volumetric soil water content (VSWC) and evapotranspiration (ET) rates were recorded every 3 days. Turfgrass quality (TQ) was observed weekly and root weight was measured at the end of a 6-week study. ‘Aussie Green’ and ‘Celebration’ produced the highest TQ rating (>7) at week 4 when watered daily. After 4 weeks of the 5-day irrigation interval, all cultivars showed unacceptable quality ratings (<7). However, ‘Aussie Green’ and ‘Celebration’ were able to maintain an acceptable TQ rating (7), compared to ‘Arizona Common’ (5.1) and ‘Tift No.3’ (5.8) at week 2 (5-day treatment). ‘Celebration’ produced 114% and 97% greater root weight than ‘Tifsport’ and ‘Aussie Green’, respectively, when pooled across all irrigation treatments. At the 15-day irrigation interval treatment, six bermudagrass cultivars pooled together produced 78%, 22%, and 11% greater root weight vs. control, 5-day, and 10-day treatments, respectively. When pooled for all treatments, ‘Aussie Green’ and ‘Celebration’ VSWC was 5% and 7% lower than ‘Tift No.3’, and ET rates were 26% and 30% greater than ‘Arizona Common’. Based on these results, irrigating bermudagrass in 5-day intervals should be carefully monitored.