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This article in SSSAJ

  1. Vol. 59 No. 6, p. 1694-1701
     
    Received: Aug 23, 1994
    Published: Nov, 1995


    * Corresponding author(s): wendell_gilliam@ncsu.edu
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doi:10.2136/sssaj1995.03615995005900060027x

Water Table Management Effects on Denitrification and Nitrous Oxide Evolution

  1. B. A. Kliewer and
  2. J. W. Gilliam 
  1. Department of Soil Science, North Carolina State Univ., 3305 Williams Hall, Box 7619, Raleigh, NC 27695-7619

Abstract

Abstract

Previous research suggested that using controlled drainage to elevate the water table reduces NO3 contamination of surface water by enhancing denitrification. The C2H2 inhibition technique was used to study denitrification and N2O evolution using 56-cm-long, undisturbed cores of Cape Fear loam (clayey, mixed, thermic Typic Umbraquult) maintained in the field and subjected to three static water table levels (15, 30, and 45 cm). Results showed that intermittent C2H2 exposure did not (i) affect soil inorganic N distribution between NH4+ and NO3, (ii) diminish inhibition of N2O reduction during subsequent C2H2 exposure, or (iii) induce C2H2 decomposition. Denitrification from 1 Nov. 1993 through 21 Apr. 1994 (172 d) was 341 kg N ha−1 for the 15-cm water table treatment, 260 kg N ha−1 for the 30-cm water table treatment, and 86 kg N ha−1 for the 45-cm water table treatment. Denitrification was maximum at the lowest monitored zone (36–54 cm) for each water table treatment. Total N2O evolution was 9 kg N ha−1 for the 15-cm water table treatment, 4 kg N ha−1 for the 30-cm water table treatment, and 2 kg N ha−1 for the 45-cm water table treatment. Nitrous oxide evolution was positively correlated with mean soil temperature (10-cm depth) until low NO3 levels appeared to limit denitrification. Since steady-state diffusion was not reached, estimates of N2 evolution, using N2O evolution in the presence of C2H2, were underestimated 12-fold. Evolved N2O-N represented only 2% of denitrification in the soil core (0–54 cm) for each water table treatment. Drainage control to elevate the water table enhanced denitrification and N2O evolution, reducing the potential for N transport with subsurface drainage to surface water.

The use of trade names in this publication does not imply endorsement by the North Carolina Agric. Res. Serv. of the products named nor criticism of similar ones not mentioned.

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