Microbial Biomass Carbon (MBC)

AUS-TDG-AGR-SMB General Low confidence

Benchmark Value

No specific value — see range

Range: 600 to 1000 mg/kg

Optimal Range: 600 to 1000

Direction: Higher is desirable ↑

Form: OptimalRange

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

OptimalRange Primary Point Guard OptimalRange Guard Point Guard OptimalRange Guard Point Guard LowerThreshold Guard

Evidence & Context

An MQ approaching 4-5% (which could translate to MBC values exceeding 500-600 mg/kg in soils with 1.5-2% SOC) suggests high ecological function and efficiency.

Metric Definition:

Microbial Biomass Carbon (MBC) range supporting robust and efficient ecological functions.

Benchmark Definition:

Optimal MBC range indicating high ecological function and efficiency.

Justification:

MQ values in the 4-5% range indicate a highly active and efficient microbial community.

Sources (1)

Preview of Regenerative opportunities for building soil biological resilience – a ..., accessed May 11, 2025

Regenerative opportunities for building soil biological resilience – a ..., accessed May 11, 2025 GreyLiterature

Soil and fertilizer phosphorus: Effects on plant P supply and mycorrhizal development - Canadian Science Publishing, accessed August 28, 2025

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Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Farming systems can affect soil biology, soil pathogens and system ...

Contextual Support Journal

Farming system impact on soil biology and functions

View Source

Limitations of soil microbial biomass carbon as an indicator of soil pollution in the field

Contextual Support Journal

The Long-Term Effect of Biochar on Soil Microbial Abundance, Activity and Community Structure Is Overwritten by Land Management - Frontiers

View Source

Context

Region Australia
Biome Temperate Dry Woodlands & Native Grasslands
Land Use Agricultural Crop Production
Assessment Pristine Reference
Evidence Type HealthyOperationalRange

Lifecycle

Status Active
Version 2
Effective From 20 Mar 2026

Notes

This range is higher than current average MBC levels in the biome, suggesting potential for further enhancement. Accepted by operator on 2026-03-20 07:01 UTC — superseded v1 (#763)

Related Benchmarks

Other benchmarks in the AUS-TDG-AGR-SMB family.