Evaluating soil microbial metabolic activity in response to two plant biostimulants using the Biolog Ecoplate™ method
DOI:
https://doi.org/10.24193/subbbiol.2026.1.08Keywords:
soil microbial activity, Biolog EcoPlate™, plant biostimulants, microbial biostimulants, substrate utilization patterns, functional indicesAbstract
Biostimulants are emerging as viable alternatives to chemical fertilizers, offering a pathway toward more sustainable and environmentally friendly agricultural practices. Their effectiveness, however, is influenced by a range of environmental and biological conditions, making outcomes variable. Evidence suggests that biostimulants may exert their influence by modifying the metabolic activity and composition of soil microbial communities – key drivers of nutrient cycling. This study aimed to assess microbial activity in untreated soil and soil treated with two distinct biostimulants: a seaweed-derived product (PStim) and a microbial-based formulation (MbPB), under greenhouse conditions. Microbial dynamics were evaluated using the Biolog EcoPlate™ method, focusing on substrate utilization pattern. Soil respiration rate was also estimated. No significant changes in soil chemical properties were observed following biostimulant application. Nonetheless, all variants demonstrated high metabolic activity, as indicated by average well-color development (AWCD), with notable differences in substrate preferences. Functional indices pointed to increased metabolic diversity and evenness in biostimulant-treated soils, potentially linked to the targeted stimulation of specific microbial taxa.
Article history: Received 16 February 2026; Revised 17 June 2026;
Accepted 19 June 2026; Available online 25 June 2026.
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