Bermudagrass Growth, Total Nonstructural Carbohydrate Concentration, and Quality as Influenced by Nitrogen and Potassium

Abstract

Hybrid bermudagrass cultivars (Cynodon dactylon L. × C. transvaalensis Burtt‐Davy) ditfer in their responses to N and K for growth, total nonstructural carbohydrate (TNC) concentration, and turf quality scores. This 1995 research was conducted in Florida to compare responses of two bermudagrass cultivars to N and K under long‐day (>13 h) and short‐day (<13 h) conditions in a glasshouse. Evaluations were made concerning shoot and root growth, TNC concentration, and quality scores of ‘FloraDwarf’ and ‘Tifdwarf’ bermudagrass during establishment in a coarse sand medium. Experimental design under each photoperiod was a randomized complete block with factorial treatments consisting of two cultivars, four rates of N, four rates of K, and four replications. Data were analyzed by fitting multiple regression equations starting with a second order polynomial model. Growth of FloraDwarf was highly responsive to photoperiod, in that decreased daylengths reduced growth. No growth differences were found in Tifdwarf due to daylength. Growth increased in response to N in both cultivars, while growth response to K varied by cultivar. Both cultivars accumulated higher levels of TNC under short day conditions, with higher levels in FloraDwarf. Nitrogen fertilization reduced TNC levels in FloraDwarf under short days and in Tifdwarf under long days, while K fertilization reduced TNC levels in Tifdwarf under short days. Quality scores in both cultivars increased in response to N under long days, and in response to both N and K under short days. Results of these studies indicated that growth, TNC accumulation, and quality differed due to cultivar, photoperiod, and rates of N and K.