Effect of Mowing Height on DLI Requirements for Warm-Season Turfgrass.

Bermudagrass is considered to be one of the least shade tolerant warm-season turfgrasses.  Mowing height has been determined to affect the amount of light required by a turfgrass to maintain acceptable quality (TQ).  Because of its cultural management, bermudagrass putting greens require high levels of irradiance and tolerate little shade.  Greenhouse trials were conducted to determine daily light integral (DLI) requirements for six warm-season turfgrasses maintained at two different mowing heights.  TifEagle, Jones Dwarf, and Champion bermudagrass (Cynodon dactylon X C. transvaalensis) were maintained at 3.2 and 4.8 mm.  Tifway bermudagrass (C. dactylon X C. transvaalensis), Celebration bermudagrass (C. dactylon), and SeaDwarf seashore paspalum (Paspalum vaginatum) were maintained at 12.7 and 38.1 mm.  Supplemental lighting and shade cloth were used to create four light treatments: 55.3, 38.1, 26.4, and 14.6 mol m^-1 d^-1 average daily DLI.  Lower mowing heights increased DLI requirements to maintain minimum acceptable TQ by an average of 6.5±3.0 mol m^-1 d^-1.  Under lower mowing height, Jones Dwarf had the highest DLI requirement at 44.0 mol m^-1 d^-1, and Celebration had the lowest at 24.6 mol m^-1 d^-1.  At the higher mowing heights, Jones Dwarf had the highest DLI requirement at 37.1 mol m^-1 d^-1, and Celebration had the lowest at 14.5 mol m^-1 d^-1.