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Aeration effects on CO 2 , N 2 O, and CH 4 emission and leachate composition of a forest soil
Author(s) -
Vor Torsten,
Dyckmans Jens,
Loftfield Norman,
Beese Friedrich,
Flessa Heiner
Publication year - 2003
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200390010
Subject(s) - aeration , microcosm , leachate , environmental chemistry , soil water , chemistry , denitrification , leaching (pedology) , nitrification , anoxic waters , nitrate , nitrogen , environmental science , soil science , organic chemistry
The availability of O 2 is one of the most important factors controlling the chemical and biological reactions in soils. In this study, the effects of different aeration conditions on the dynamics of the emission of trace gases (CO 2 , N 2 O, CH 4 ) and the leachate composition (NO 3 ‐ , DOC, Mn, Fe) were determined. The experiment was conducted with naturally structured soil columns (silty clay, Vertisol) from a well aerated forest site. The soil monoliths were incubated in a microcosm system at different O 2 concentrations (0, 0.001, 0.005, 0.01, 0.05, and 0.205 m 3 m ‐3 in the air flow through the headspace of the microcosms) for 85 days. Reduced O 2 availability resulted in a decreased CO 2 release but in increased N 2 O emission rates. The greatest cumulative N 2 O emissions (= 1.6 g N 2 O‐N m ‐2 ) were observed at intermediate O 2 concentrations (0.005 and 0.01 m 3 m ‐3 ) when both nitrification and denitrification occurred simultaneously in the soil. Cumulative N 2 O emissions were smallest (= 0.05 g N 2 O‐N m ‐2 ) for the aeration with ambient air (O 2 concentration: 0.205 m 3 m ‐3 ), although nitrate availability was greatest in this treatment. The emission of CH 4 and leaching of Mn and Fe were restricted to the soil columns incubated under completely anoxic conditions. The sequence of the reduction processes under completely anoxic conditions complied with the thermodynamic theory: soil nitrate was reduced first, followed by the reduction of Mn(IV) and Fe(III) and finally CO 2 was reduced to CH 4 . The re‐aeration of the soil columns after 85 days of anoxic incubation terminated the production of CH 4 and dissolved Fe and Mn in the soil but strongly increased the emission rates of CO 2 and N 2 O and the leaching of NO 3 ‐ probably because of the accumulation of DOC and NH 4 + during the previous anoxic period.