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Comparison of Field Denitrification Rates Determined by Acetylene‐Based Soil Core and Nitrogen‐15 Methods
Author(s) -
Parkin Timothy B.,
Sexstone Alan J.,
Tiedje James M.
Publication year - 1985
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/sssaj1985.03615995004900010019x
Subject(s) - denitrification , loam , nitrate , nitrous oxide , soil water , environmental science , acetylene , nitrogen , soil test , soil science , chemistry , environmental chemistry , organic chemistry
A soil core method to measure field denitrification rates was evaluated by comparing the results with denitrification rates measured by the 15 N difference method. In the core method, acetylene amended air was recirculated through an undisturbed soil core and short‐term (ca. 1 h) nitrous oxide production monitored. Denitrification rates were obtained on soil cores from two field sites and a set of sieved, repacked soil cores in a laboratory incubation. Cumulative N‐losses were estimated by interpolating between sample dates. Denitrification rates obtained by the core method were found to approximate a log normal distribution at both sites studied and at all sampling times. Statistical calculations appropriate for this distribution resulted in improved estimates of the mean rates and confidence intervals. For the 15 N difference method, 15 N enriched nitrate was added to microplots of 30 cm diameter and the total gaseous losses were estimated by considering the change in the total nitrate pool, the isotope ratio of that pool and the 15 N not recovered from the microplots. Experiments were conducted over periods of 32 to 45 d on sandy loam and clay loam soils, respectively. Denitrification rates from the acetylene‐core method were not significantly different than the estimates by the 15 N method. Denitrification rates as measured by both methods were highly variable.