TY - JOUR

T1 - Denitrification rate determined by nitrate disapperance is higher than determined by nitrous oxide production with acetylene blockage

AU - Yu, Kewei

AU - Struwe, Sten

AU - Kjøller, Annelise

AU - Chen, Guanxiong

N1 - Keywords: Denitrification; Nitrous oxide; Nitric oxide; Acetylene; Nitrate reduction

PY - 2008

Y1 - 2008

N2 - A mixed beech and spruce forest soil was incubated under potential denitrification assay (PDA) condition with 10% acetylene (C2H2) in the headspace of soil slurry bottles. Nitrous oxide (N2O) concentration in the headspace, as well as nitrate, nitrite and ammonium concentrations in the soil slurries were monitored during the incubation. Results show that nitrate disappearance rate was higher than N2O production rate with C2H2 blockage during the incubation. Sum of nitrate, nitrite, and N2O with C2H2 blockage could not recover the original soil nitrate content, showing an N imbalance in such a closed incubation system. Changes in nitrite and ammonium concentration during the incubation could not account for the observed faster nitrate disappearance rate and the N imbalance. Non-determined nitric oxide (NO) and N2 production could be the major cause, and the associated mechanisms could vary for different treatments. Commonly applied PDA measurement likely underestimates the nitrate removal capacity of a system. Incubation time and organic matter/nitrate ratio are the most critical factors to consider using C2H2 inhibition technique to quantify denitrification. By comparing the treatments with and without an antibiotic, the results suggest that microbial N uptake probably played a minor role in N balance, and other denitrifying enzymes but nitrate reductase could be substantially synthesized during the incubation.

AB - A mixed beech and spruce forest soil was incubated under potential denitrification assay (PDA) condition with 10% acetylene (C2H2) in the headspace of soil slurry bottles. Nitrous oxide (N2O) concentration in the headspace, as well as nitrate, nitrite and ammonium concentrations in the soil slurries were monitored during the incubation. Results show that nitrate disappearance rate was higher than N2O production rate with C2H2 blockage during the incubation. Sum of nitrate, nitrite, and N2O with C2H2 blockage could not recover the original soil nitrate content, showing an N imbalance in such a closed incubation system. Changes in nitrite and ammonium concentration during the incubation could not account for the observed faster nitrate disappearance rate and the N imbalance. Non-determined nitric oxide (NO) and N2 production could be the major cause, and the associated mechanisms could vary for different treatments. Commonly applied PDA measurement likely underestimates the nitrate removal capacity of a system. Incubation time and organic matter/nitrate ratio are the most critical factors to consider using C2H2 inhibition technique to quantify denitrification. By comparing the treatments with and without an antibiotic, the results suggest that microbial N uptake probably played a minor role in N balance, and other denitrifying enzymes but nitrate reductase could be substantially synthesized during the incubation.

KW - Faculty of Science

KW - Denitrifikation

KW - lattergas udslip

KW - Denitrification

KW - Nitrous oxide

KW - Nitric oxide

KW - Acetylene

KW - Nitrate reduction

U2 - 10.1016/j.ecoleng.2007.09.006

DO - 10.1016/j.ecoleng.2007.09.006

M3 - Journal article

VL - 32

SP - 90

EP - 96

JO - Ecological Engineering

JF - Ecological Engineering

SN - 0925-8574

IS - 1

ER -