Microbial Biomass Carbon (MBC)
Benchmark Value
Scoring Curve
This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 11 benchmarks together — the OptimalRange form drives the primary score, while 10 guard(s) constrain the result.
Evidence & Context
Based on this evidence, a value below 150 mg/kg can be confidently proposed as a lower critical threshold for MBC in this system.
Lower critical threshold for Microbial Biomass Carbon (MBC) indicating onset of degradation
Lower critical threshold below which MBC levels signify substantial impairment of ecosystem functions.
This threshold aligns with severe reductions observed in sites undergoing degradation, associated with heavy grazing pressure and loss of perennial tussocks.
Sources (1)
A Description of the ECCOSAT Experimental Site at Hillgrove near Charters Towers, north Queensland - ResearchGate
View SourceSupporting Sources (3)
Additional references from the underlying research that informed this benchmark.
Microbiological Indicators for Assessing the Effects of Agricultural Practices on Soil Health: A Review - MDPI, accessed August 13, 2025,
View Source
Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter - ResearchGate
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The effects of burning and grazing of dry tropical Indian savanna on the level of available nutrient pools and microbial C, N and P
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