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 7 benchmarks together — the OptimalRange form drives the primary score, while 6 guard(s) constrain the result.
Contributing Benchmarks
Evidence & Context
Based on the available data, values approaching the 100–150 mg/kg range likely represent this functionally impaired state in Australian dryland cropping systems.
Microbial Biomass Carbon (MBC) is a measure of the carbon contained within the living component of soil organic matter (SOM), which is composed predominantly of bacteria and fungi.
This benchmark defines the range of microbial biomass carbon values indicating a functionally impaired soil state in Australian dryland cropping systems, where soil biological function is compromised.
This threshold is not absolute but is conditional on other soil stressors. The risk of functional collapse is severely amplified when low MBC is combined with soil acidity (pH < 5.0), a condition where the system's multifunctionality becomes critically dependent on its microbial population.
Sources (1)
Soil and fertilizer phosphorus: Effects on plant P supply and mycorrhizal development - Canadian Science Publishing, accessed August 28, 2025
View SourceSupporting Sources (1)
Additional references from the underlying research that informed this benchmark.
Prospects for summer cover crops in southern Australian semi-arid cropping systems | Request PDF - ResearchGate
View Source