Microbial responses to fluctuation of soil aeration status and redox conditions |
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| Authors: | T Picek M ?imek H ?antr??ková |
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| Institution: | (1) Institute of Soil Biology, Academy of Sciences of the Czech Republic, Na sádkách 7, CZ-370 05 České Budějovice, Czech Republic e-mail: tompi@upb.cas.cz Tel.: +420-38-5300134 Fax: +420-38-5300133, CZ;(2) Faculty of Biological Sciences, University of South Bohemia, České Budějovice, Czech Republic, CZ |
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| Abstract: | The response of the microbial community to changes in aeration status, from oxic to anoxic and from anoxic to oxic, was determined
in arable soil incubated in a continuous flow incubation apparatus. Soil incubated in permanently oxic (air) and/or anoxic
(O2-free N2) conditions was used as the control. Before experiments soil was preincubated for 6 days, then aeration status was changed
and glucose added. Glucose concentration, extractable C, CO2 production, microbial biomass, pH and redox potential were determined 0, 4, 8, 12, 16, 24, 36 and 48 h after change of aeration
status. If oxic conditions were changed to anoxic, the amount of glucose consumed was reduced by about 60%, and CO2 production was 10 times lower at the end of incubation compared to the control (permanently oxic conditions). Microbial biomass
increased by 114% in glucose-amended soil but did not change in unamended soil. C immobilization prevailed over C mineralization.
Redox potential decreased from +627 mV to –306 mV. If anoxic conditions were changed to oxic, consumption of glucose and CO2 evolution significantly increased, compared to permanently anoxic conditions. Microbial biomass did not change in glucose-amended
soil, but decreased by 78% in unamended soil. C mineralization was accelerated. Redox potential increased from +238 to +541 mV.
The rate of glucose consumption was low in anoxic conditions if soil was incubated in pure N2 but increased significantly when incubation was carried out in a CO2/N2 mixture.
Received: 6 January 1999 |
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| Keywords: | Aeration status Glucose Microbial biomass Redox potential Anoxic conditions |
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