Monday, November 13, 2006 - 8:15 AM
68-4
Nitrogen Recovery, Use Efficiency, and Soil Losses of Three Cool-Season Turfgrass.
There is concern that nitrogen (N) losses from regularly fertilized turf is negatively affecting water quality. The purpose of this study therefore, is to not only assess soil N losses but to also assess above-ground plant responses to determine environmentally responsible N fertility programs for lawns. This two and one half year field study measured dry matter yield (DMY), leaf tissue N content, and potential soil N loss of eight N-programs which varied by N amount, 0 – 196 kg N ha-1 yr-1, and seasonal application timing of three cool-season lawn species: Kentucky bluegrass (Poa pratensis L.) (KBG), perennial ryegrass (Lolium perenne L.) (PRG), and turf-type tall fescue (Festuca arundinacea Schreb.) (TTTF). Dry matter yields for the study differed substantially between species and ranked, TTTF>KBG>PRG, with 9,426, 7,750, and 7,011 kg ha-1, respectively. Leaf tissue N ranked PRG>KBG>TTTF with 35.2, 33.9, 31.5 g kg -1, respectively. Nitrogen uptake (NUP), N recovery (NREC), and N use efficiency (NUE) was calculated, where TTTF (276 kg ha-1) had the greatest NUP followed by KBG (269 kg ha-1) and PRG (249 kg ha-1). Apparent NREC ranked, TTTF>PRG>KBG with 44, 41, and 39 %, of applied N. For NUE, values ranked 13.3, 11.1, 10.1 kg DMY kg N -1 for TTTF, PRG, and KBG respectively. Soil nitrate (NO3- - N) and ammonium (NH4+ -N) concentrations in soil solution as measured by suction cup lysimeters were low, < 1 mg L-1, throughout most of the study. Where N-loss is of concern a deep rooted efficient species like TTTF which is capable of producing high DMYs, NUP, NREC and NUE should be considered.
Recorded presentation