INQUINOA   21218
INSTITUTO DE QUIMICA DEL NOROESTE
Unidad Ejecutora - UE
artículos
Título:
A new approach to determine soil microbial biomass by calorimetry
Autor/es:
SESTO CABRAL, MARÍA EUGENIA; E. ELIZABETH SIGSTAD
Revista:
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
Editorial:
Springer
Referencias:
Lugar: Budapest; Año: 2010 p. 23 - 29
ISSN:
1418-2874
Resumen:
A method to determine soil microbial biomass
(SMB) by isothermal calorimetry is reported. Soil samples
ranging in pH from 6.2 to 9.4 and different textures were
used to develop the method. Soil at 60% of its field
capacity humidity was amended with a previously determined
amount of glucose as to give the maximal response
of CO2 evolution. Then, an aliquot was weighed in the
calorimeter ampoule and specific thermal power (p)time
(t) curves were obtained at 25 C. After 12 h, a vial
containing a 0.5 M NaOH solution was introduced to
determine the specific thermal power due to CO2 evolution,
pCO2 during 12 h. Then, the vial was removed and the
experiment continued for 12 h. Specific thermal power
due to CO2 evolution was converted to rate (CO2-C/
mm3 g-1 h-1) by using the heat of reaction of CO2 with
NaOH and the molar volume. This value was further
converted into SMB/lg g-1 by using a conversion factor of
32.4. A guide to perform the calculations is given. Values
of log SMB were linearly related with values of log
p giving a similar relation to a previously reported where
SMB was determined by conventional methods.