Effect Of Shade Duration On Three Warm-Season Turfgrasses.

Seasonal weather patterns affect the amount of cloud cover in Florida and other areas throughout the year.  Cloud cover can reduce available light by an average of 45%, and can be reduced even further due to shortened day lengths during the winter. In warm-season turfgrasses, this light reduction could lead to a decline in turfgrass quality and altered physiology.  Field trials were conducted to evaluate the effect of shade duration on turfgrass quality in three bermudagrass cultivars: Tifway and Jones Dwarf bermudagrass (Cynodon dactylon X C. transvaalensis), and Celebration bermudagrass (C. dactylon).  Four shade intervals were implemented (no shade, weekly, biweekly, monthly) for a period of eight weeks using 50% shade for Jones Dwarf, and 50% and 70% shade for Tifway and Celebration.  Average daily light integral for the experiment was 47.2±8.9 mol m^-2 d^-1.  Under 50% shade, significant differences in quality occurred at 1, 2, and 6 weeks after initial shading (WAIS) for Jones Dwarf, Celebration, and Tifway, respectively.  For 70% shade, quality differences were observed at 2 WAIS for Celebration and 4 WAIS for Tifway.  All shade treatments had below acceptable turfgrass quality for at least one week.   At 8 WAIS, only weekly shading was significantly different from the unshaded control for each turfgrass.