Growth of Kentucky Bluegrass as Influenced by Nitrogen and Trinexapacethyl

The experiment aimed to evaluate the effects of N and trinexapac-ethyl (TE) to the growth of Kentucky bluegrass. By using the method of randomized blocks design, 4 N levels, 0 (N1), 20 (N2), 25 (N3), and 30 (N4) kg N ha−1 mon−1, with TE at 0 (T1), 312.5 (T2) and 625 (T3) mL ha−1 every 10 d effect on the total height, clippings and chlorophyll concentration of Kentucky bluegrass were evaluated. Results showed that total height and total clippings of Kentucky bluegrass were reduced by treating with TE and increased by treating with N. Kentucky bluegrass treated with 312.5 and 625 mL ha−1 per 10 d had total clippings and total height reduced 30 and 45% under different N application level. The N× TE interaction was significant for the chlorophyll concentration of Kentucky bluegrass. The chlorophyll concentration of Kentucky bluegrass treated with TE at 625 mL ha−1 every 10 d was significantly higher than that of Kentucky bluegrass treated with 312.5 mL ha−1 every 10 d at the same N level. The chlorophyll concentration of turfgrass treated with TE at 625 mL ha−1 every 10 d receiving 30 kg N ha−1 month−1 was the highest. Based on the index of turf growth and the chlorophyll concentration, turfgrass receiving 20 or 30 kg N ha−1 month−1 with 625 mL TE ha−1 every 10 d could balance the problem of mowing frequency and growth quickly while keeping a good quality.