The influence of some physicochemical parameters on the microbial growth in soils

Microcalorimetric techniques have been used to study the influence of different physicochemical parameters on microbial growth in different soils in Galicia (NW Spain). The study was carried out using a 4 channels Thermal Activity Monitor (Thermometric, Sweden). Two types of soil, humic cambisol and umbric regosol, with different uses, vineyard, orchard, maize field, and scrubland, were investigated. Microbial activity in all the soils studied was stimulated by the addition of 1.25 mg of glucose g−1 soil. The power–time curves recorded from every experiment were analysed and from these analyses characteristic parameters such as peak time, peak height and microbial growth rate constants were determined. The influence of different environmental parameters, temperature (ambience and soil), moisture content (sample and residual), pH in water, and C/N ratio, were considered.