Fungal:Bacterial Ratio

AUS-TDG-CON-SFB General High confidence

Benchmark Value

No specific value — see range

Range: 1.6 to 2.1 ratio

Optimal Range: 1.6 to 2.1

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.

Evidence & Context

While the F:B ratio ranges from 1.8 (1.6~2.1) in savanna to 8.6 (6.7~11.0) in tundra.

Metric Definition:

Topsoil (0-30 cm) ratio of fungal biomass carbon to bacterial biomass carbon derived via global PLFA profiling.

Benchmark Definition:

Global baseline range of fungal to bacterial biomass carbon ratio for savanna and dry open woodland soils.

Justification:

This global peer-reviewed meta-analysis synthesizes thousands of PLFA observations, establishing the climate-matched baseline range of F:B ratios for open woodland/savanna soils.

Sources (1)

Global biogeography of fungal and bacterial biomass carbon in topsoil

Biogeographic patterns of soil bacterial and fungal biomass C and their ratios across major biomes

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Supporting Sources (7)

Additional references from the underlying research that informed this benchmark.

Different responses of soil fungal and bacterial communities to nitrogen addition in a forest grassland ecotone - Frontiers

Direct Evidence Journal

Soil microbiology factsheet

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Fungal/bacterial ratios in grasslands with contrasting nitrogen ...

Direct Evidence

Fungal/bacterial ratios in grasslands with contrasting nitrogen ...

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Fungal/bacterial ratios in grasslands with contrasting nitrogen management - ResearchGate, accessed July 18, 2025

Direct Evidence GreyLiterature

Fungal/bacterial ratios in grasslands with contrasting nitrogen management - ResearchGate

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Fungus and bacteria OH MY!! F:B Ratios explained - Mass Hydroponics

Contextual Support GreyLiterature

Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - PMC - PubMed Central, accessed July 21, 2025

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Response of soil microbial functionality and soil properties to ...

Contextual Support Journal

Pastures to woodlands: Changes in soil microbial communities and carbon following reforestation | Request PDF - ResearchGate

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Role of Soil Fungus | Ohioline - The Ohio State University, accessed on June 5, 2025

Contextual Support GreyLiterature

Role of Soil Fungus | Ohioline - The Ohio State University, accessed on June 7, 2025,

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Unlocking the power of microbes to enhance the soil

Contextual Support GreyLiterature

Unlocking the power of microbes to enhance the soil

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Context

Region Australia
Biome Temperate Dry Woodlands & Native Grasslands
Land Use Conservation / Protected Natural Areas
Assessment Pristine Reference
Vegetation Woodland
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 19 Jun 2026

Notes

The 1.6 to 2.1 range represents the 95% confidence interval surrounding the global savanna mean F:B ratio of 1.8.

Related Benchmarks

Other benchmarks in the AUS-TDG-CON-SFB family.