Carbon sequestration-related eco-indicators in long-term field trials

The sensitivity of biodiversity and ecosystem functions to climate and land-use changes needs to be estimated by the set of eco-indicators linking physical and biochemical properties of the soil matrix with microbial functional traits and C transformation processes.We tested reliability of two basic eco-indicators to capture the complexity of soil processes across scales: i) metabolic quotient (qCO2), i.e. the ratio of respiration-to-microbial biomass and ii) the ratio of microbial biomass-to-soil C content (MBC/SOC). The sensitivity of these eco-indicators was evaluated across different experimental treatments of long-term field experiments within the same geographical site at agricultural station in Bad Lauchstädt, Germany. Both qCO2 and MBC/SOC provided complementary information and were sensitive to land use, fertilization and climate at the field scale. Among the land-use tested, an extensive meadow demonstrated most promising response to the future climate conditions. We will also discuss an ability of the set of these coupled indexes (qCO2 and MBC/SOC) to mirror the carbon sequestration potential in agricultural soils.