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Crop Science Abstract - TURFGRASS SCIENCE

Nitrogen Use in Tifway Bermudagrass, as Affected by Trinexapac-Ethyl


This article in CS

  1. Vol. 44 No. 2, p. 595-599
    Received: July 5, 2002

    * Corresponding author(s): mfagerne@oznet.ksu.edu
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  1. Matthew J. Fagerness *a,
  2. Daniel C. Bowmanb,
  3. Fred H. Yelvertonb and
  4. Thomas W. Ruftyb
  1. a Dep. of Horticulture, Forestry, and Recreation Resources, Kansas State Univ., 2021 Throckmorton, Manhattan, KS 66506-5507
    b Crop Science Dep., North Carolina State Univ., 100 Derieux St. Box 7620, Raleigh, NC 27695-7620


Nutrient movement from turfgrass systems into surface and ground water is a public concern. Data indicate that actively growing turf rapidly immobilizes applied N, thus restricting nutrient movement. It is possible, however, that growth suppression with plant growth regulators (PGRs) could reduce N demand and thus N uptake, resulting in greater leaching losses. An experiment was conducted with column lysimeters to investigate the effects of trinexapac-ethyl (TE) on nitrate leaching and N-use efficiency in Tifway bermudagrass (Cynodon dactylon × C. transvaalensis). The experiment was conducted in a growth chamber with day/night temperature set at 29/24°C and a 12-h photoperiod. Trinexapac-ethyl was applied twice at 4-wk intervals at 0.11 kg a.i. ha−1 Ammonium nitrate (AN) was applied at 50 kg N ha−1 2 wk after each TE application, and again 6 wk after the second TE application. Separate sets of columns received 15N-labeled AN for the first two applications. Irrigation was scheduled to provide a leaching fraction of ≈50%; leachate was collected after each irrigation and analyzed for nitrate and ammonium. Cumulative nitrate leaching was unaffected by TE after the first two N applications, but was reduced ≈60% by TE following the third N application. Trinexapac-ethyl reduced 15N allocation to clippings by ≈25% and increased 15N allocation to roots and rhizomes; total recovery of applied 15N in tissues was ≈65%. Results demonstrate chemical growth suppression with TE does not reduce N uptake or increase nitrate leaching from bermudagrass.

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