Utilization of a Portable Spectrophotometer for Evaluating Traffic and Nitrogen Rate Effects on Hybrid Bermudagrass Turf.

A studied was initiated in the summer of 2013 to evaluate seeding/sprigging, nitrogen, and traffic rates on establishment and survivability of hybrid bermudagrass (Cynodon dactylon [L.] Pers. var. dactylon x C. transvaalensis Burtt-Davy) established late.  The study was replicated in two different locations, Lexington and Bowling Green, KY.  Three bermudagrass cultivars were utilized; ‘Tifway 419’, ‘Riviera’, and ‘Latitude 36’.  Riviera seeding rates consisted of 11.8, 23.6, and 47.2 g/m². Tifway 419 and Latitude 36 sprigging rates were 34.6, 69.2, and 138.4 m³/ha.  Nitrogen was applied weekly at rates of 12.2, 24.4, and 48.8 kg/ha for a total of seven applications.  Plots were seeded/sprigged on 7/15/2013.  Traffic treatments were applied utilizing a Cady traffic simulator which included one and three events per week.  Traffic treatments began on 9/2/2013 and continued through 11/1/2013.  Percent bermudagrass cover, percent turfgrass disturbance, bermudagrass color, and turf quality were visually rated.   In addition, turf was analyzed by a HunterLab miniscan EZ colorimeter.  Spectra included an L* range (light to dark), A* range (red to green), and a B* range (yellow to blue).  Colorimeter data showed significant differences among main effects.  Latitude 36 and Riviera possessed significantly lower L* (darker) values compared to Tifway 419.  Latitude 36 also showed lower A* (greener) values than Riviera and Tifway 419.  The low nitrogen rate possessed higher L* (lighter) values than the medium and high nitrogen rates.  In addition, a significant difference in B* (blue) values was observed among all nitrogen treatments.  Finally, L*, A*, and B* values were significantly different between high and low traffic treatments.  Results were similar to the visual observations.  These results, along with the portability and ease of use of the HunterLab miniscan EZ colorimeter, indicate that a portable spectrophotometer can be a helpful instrument in turfgrass field research.