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Water Table Management Effects on Denitrification and Nitrous Oxide Evolution
Author(s) -
Kliewer B. A.,
Gilliam J. W.
Publication year - 1995
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1995.03615995005900060027x
Subject(s) - denitrification , nitrous oxide , water table , loam , chemistry , zoology , table (database) , drainage , environmental science , soil water , environmental chemistry , hydrology (agriculture) , soil science , nitrogen , ecology , groundwater , biology , geology , geotechnical engineering , organic chemistry , computer science , data mining
Previous research suggested that using controlled drainage to elevate the water table reduces NO 3 − contamination of surface water by enhancing denitrification. The C 2 H 2 inhibition technique was used to study denitrification and N 2 O 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 C 2 H 2 exposure did not (i) affect soil inorganic N distribution between NH 4 + and NO 3 − , (ii) diminish inhibition of N 2 O reduction during subsequent C 2 H 2 exposure, or (iii) induce C 2 H 2 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 N 2 O 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 NO 3 − levels appeared to limit denitrification. Since steady‐state diffusion was not reached, estimates of N 2 evolution, using N 2 O evolution in the presence of C 2 H 2 , were underestimated 12‐fold. Evolved N 2 O‐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 N 2 O evolution, reducing the potential for N transport with subsurface drainage to surface water.