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This article in JEQ

  1. Vol. 35 No. 5, p. 1678-1685

    * Corresponding author(s): bremer@ksu.edu
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Nitrous Oxide Fluxes in Turfgrass

  1. Dale J. Bremer *
  1. Dep. of Horticulture, Forestry & Recreation Resources, 2021 Throckmorton Hall, Kansas State Univ., Manhattan, KS 66506


Urban ecosystems are rapidly expanding and their effects on atmospheric nitrous oxide (N2O) inventories are unknown. Our objectives were to: (i) measure the magnitude, seasonal patterns, and annual emissions of N2O in turfgrass; (ii) evaluate effects of fertilization with a high and low rate of urea N; and (iii) evaluate effects of urea and ammonium sulfate on N2O emissions in turfgrass. Nitrogen fertilizers were applied to turfgrass: (i) urea, high rate (UH; 250 kg N ha−1 yr−1); (ii) urea, low rate (UL; 50 kg N ha−1 yr−1); and (iii) ammonium sulfate, high rate (AS; 250 kg N ha−1 y−1); high N rates were applied in five split applications. Soil fluxes of N2O were measured weekly for 1 yr using static surface chambers and analyzing N2O by gas chromatography. Fluxes of N2O ranged from −22 μg N2O-N m−2 h−1 during winter to 407 μg N2O-N m−2 h−1 after fall fertilization. Nitrogen fertilization increased N2O emissions by up to 15 times within 3 d, although the amount of increase differed after each fertilization. Increases were greater when significant precipitation occurred within 3 d after fertilization. Cumulative annual emissions of N2O-N were 1.65 kg ha−1 in UH, 1.60 kg ha−1 in AS, and 1.01 kg ha−1 in UL. Thus, annual N2O emissions increased 63% in turfgrass fertilized at the high compared with the low rate of urea, but no significant effects were observed between the two fertilizer types. Results suggest that N fertilization rates may be managed to mitigate N2O emissions in turfgrass ecosystems.

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