A new approach to determine soil microbial biomass by calorimetry

Authors
Sesto Cabral, María Eugenia; Sigstad, Emma Elizabeth
Publication Year
2011
Language
English
Format
article
Status
Published version
Description
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 1-2 h, a vial containing a 0.5 M NaOH solution was introduced to determine the specific thermal power due to CO 2 evolution, pCO2 during 1-2 h. Then, the vial was removed and the experiment continued for 1-2 h. Specific thermal power due to CO 2 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/μg 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.
Fil: Sesto Cabral, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina
Fil: Sigstad, Emma Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina
Subject
CALORIMETRY
MICROBIAL BIOMASS
SOIL
Otras Ciencias Químicas
Ciencias Químicas
CIENCIAS NATURALES Y EXACTAS
Otras Ciencias Biológicas
Ciencias Biológicas
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/52481