TITLE:
Calibration of CO2 Trapping in Alkaline Solutions during Soil Incubation at Varying Temperatures Using a Respicond VI
AUTHORS:
Natalya Smirnova, Michael Scott Demyan, Frank Rasche, Georg Cadisch, Torsten Müller
KEYWORDS:
Respirometer, Soil Respiration, Carbon Dioxide, Incubation
JOURNAL NAME:
Open Journal of Soil Science,
Vol.4 No.5,
April
29,
2014
ABSTRACT: Measurements of
carbon dioxide (CO2)-evolution from soils are important in
evaluating biomass and activity of soil microorganisms, as well as decomposition
of soil organic matter. The Respicond VI is a fully computerized system
allowing continuous measurement of CO2 evolution in short- and
long-term soil incubation experiments in up to 96 incubation vessels. The
measurement of CO2 evolution is based on the absorption of CO2 by an electrolyte (KOH solution) producing a change in the cell conductance
measured using two electrodes. In this study, the Respicond VI was recalibrated
yielding 174.5 mg CO2 as constant A expressing the theoretical maximum amount of CO2 absorbed in 10 ml 0.5 M KOH. This value of A corresponds to 34.9 mg CO2 ml-1 1 M KOH. The
constant A does neither depend on the
investigated incubation temperatures (5°C - 25°C) nor on the concentrations of
the KOH solutions (0.5, 0.1, 0.05 M KOH). To eliminate any influence of
changing incubation temperatures, either induced by uncertainties in
temperature control or as a part of the experimental setup, on the conductance
of KOH solution, a correction procedure was developed using a factor calculated
from changing conductance of KOH solutions in incubation vessels without soil.