Quantifying light needs for bermudagrass green establishment

In the past decade throughout the Southeast and transition zone, golf courses have been converting their greens to new ultradwarf bermudagrass cultivars. Whether the conversion is from creeping bentgrass or is replacing an older bermudagrass cultivar, a major constraint will be the successful establishment and maintenance under reduced light environments because of the poor shade tolerance of bermudagrass.

No studies have been done to determine the light requirement for bermudagrass green establishment. The objective of this research is to quantify a daily light integral requirement for successful bermudagrass green establishment. A daily light integral is the amount of photosynthetic light a plant receives each day, measured in moles of light per day (mols m-2 d-1).

A field trial was initiated in June 2013 and June 2014 at the R.R. Foil Plant Science Research Center in Starkville, Miss. Four bermudagrass cultivars, Champion, TifEagle, MiniVerde and MS-285, were established under full sunlight, 30 percent shade, 55 percent shade and 80 percent shade using a neutral density polyfiber black shade cloth. Using quantum light meters, daily light integrals (DLI) were calculated for each shade level averaged across two years. Full-sunlight plots received 42.26 mols m-2 d-1, while 30 percent shade, 55 percent shade and 80 percent shade received 31.92, 22.04 and 13.48 mols m-2 d-1, respectively. Percent cover was calculated 84 days after sprigging. Using statistical regression analysis, the amount of daily light required to reach 70 percent cover was then determined.

According to the model, DLI levels of 27.06, 28.07, 38.19 and 30.07 mols m-2 d-1 were noted for Champion, MiniVerde, MSB-285 and TifEagle, respectively. MSB-285 is an experimental bermudagrass that has a more upright growth habit compared to the other bermudagrass cultivars, and this could be a reason for the elevated light requirement.

Benton Hodges, Christian M. Baldwin, Ph.D., Maria Tomaso-Peterson, Ph.D., James McCurdy, Ph.D., Barry R. Stewart, Ph.D., and Eugene K. Blythe, Ph.D. are at Mississippi State University. Hodges can be contacted at bphodges@gmail.com for more information.