Nutrient allocation of 'TifEagle' bermudagrass as influenced by trinexapac-ethyl

Inhibiting shoot growth of dwarf bermudagrass Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davey with a plant-growth retardant, trinexapac-ethyl (TE), may redirect nutrients and photosynthate away from leaf tissue to promote root growth and improve nutrient-use efficiency. Two greenhouse experiments evaluated three rates of TE, 0.025, 0.05, and 0.075 kg a.i. ha(-1), applied every three weeks on 'TifEagle' bermudagrass for 12 weeks. Lysimeters constructed to United State Golf Association specifications were arranged in a randomized complete block design with four replications. Increased TE rates quadratically reduced clipping yield 38%-75%, improved turf quality 6%-13%, and enhanced chlorophyll concentrations 30%-70% over the untreated grass. Dry-root mass increased with TE rate 11%-37% after 12 weeks. Total clipping nutrients recovered from five sampling dates were reduced by approximately 50%, 85%, and 90% for turf receiving TE at 0.025, 0.05, and 0.075 kg ha(-1) 3 wk(-1), respectively. Thatch (stolons and rhizomes) and roots had higher nitrogen (N) concentration and retention with increased TE rate, suggesting inhibited leaf growth increased N storage in belowground plant tissue. Overall, TE may effectively enhance turf quality, root growth, and nutrient-use efficiency of dwarf-type bermudagrasses.