Microbial Metabolic Quotient is a Dynamic Indicator of Soil Health: Trends, Implications and Perspectives (Review)

Abstract: There is growing concern about the negative impact of massive fertilizer use on soil health, threatening the environmental quality and sustainability of global agricultural production. Microbial metabolic quotient (qCO₂) is an important soil health indicator, used to measure microbial C use efficiency (CUE). Soil carbon sequestration can be enhanced by increasing soil microbial biomass and CUE, ultimately improving soil health. However, the effects of long-term fertilization of agricultural soils on qCO₂ variability remain unclear. This review provides a deep insight into the concepts and factors that influence qCO₂ stability. Soil qCO₂ depends on nutrient availability, and long-term fertilization increases microbial CUE in terms of decreased qCO₂ values. Therefore, it is necessary to identify several theoretical advances and practical implications of qCO₂ for microbial control of soil carbon cycling. In addition, qCO₂ can be used as a tool for ecosystem monitoring and assessment in remediation programs due to its low-cost measurement.