Fungal:Bacterial Ratio
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 14 benchmarks together — the OptimalRange form drives the primary score, while 13 guard(s) constrain the result.
Evidence & Context
A critically low F:B ratio is indicative of a soil ecosystem that is significantly impaired and functioning poorly. Proposed Threshold: An F:B ratio of <0.3. Across a wide range of ecosystem studies, F:B ratios below this level are consistently associated with highly disturbed, heavily bacterially-dominated systems. In a pasture context, such a low ratio would signal a state of degradation characterized by poor soil structure, low soil organic matter, compaction from overgrazing, and potentially high inputs of synthetic nitrogen fertilizers.
Fungal:Bacterial (F:B) Ratio in soil microbial biomass
This lower critical threshold indicates the Fungal:Bacterial ratio below which soil is considered degraded and dysfunctional for sustainable grazing in the Tropical & Subtropical Maritime Islands biome under livestock grazing.
This threshold is based on consistent findings across ecosystem studies associating F:B ratios below 0.3 with highly disturbed, bacterially-dominated systems.
Sources (1)
ausveg - fact sheet: soil microbiology
View SourceSupporting Sources (39)
Additional references from the underlying research that informed this benchmark.
(PDF) Introducing BASE: The Biomes of Australian Soil Environments soil microbial diversity database - ResearchGate, accessed August 9, 2025,
View SourceNorfolk Island Agricultural Audit and Land Capability Assessment Report
View Source
AGRICULTURAL AUDIT & LAND USE CAPABILITY ASSESSMENT ..., accessed July 30, 2025,
View SourceAnalyzing your Fungal to Bacterial Ratio Results - microBIOMETER, accessed June 7, 2025,
View Source
Fungal/bacterial ratios in grasslands with contrasting nitrogen management, accessed July 23, 2025
View SourceAustralian Microbiome - Bioplatforms Australia, accessed July 30, 2025,
View SourceManaging Cattle Grazing on Norfolk Island, accessed July 28, 2025,
View SourceBioplatforms Australia Data Portal - Australian BioCommons, accessed July 30, 2025,
View SourceNorfolk Island Water Assessment publications and datasets - CSIRO, accessed July 30, 2025,
View SourceConservation | Lord Howe Island, accessed July 30, 2025,
View SourceCSIRO and UQ collaborate to boost Australia's ecosystem research, accessed July 30, 2025,
View SourceDo regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - CSIRO Publishing, accessed May 11, 2025,
View SourceLudwig, J.A., Bastin, G.N., Chewings, V.H., Eager, R.W., and Liedloff, A.C. (2005). Clearing savannas for use as rangelands in Queensland: Altered landscapes and water-erosion processes. Rangeland Journal, 27(2), 135-149.
View SourceFungal/bacterial ratios in grasslands with contrasting nitrogen management, accessed July 30, 2025,
View SourceFungal/bacterial ratios in grassland with contrasting nitrogen management - Wageningen University & Research, accessed July 30, 2025,
View SourceSoil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - Frontiers, accessed July 30, 2025,
View Sourcefungi to bacteria ratio chart, accessed July 30, 2025,
View SourceManaging Cattle Grazing on Norfolk Island, accessed July 30, 2025,
View SourceSoil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - PMC - PubMed Central, accessed July 30, 2025,
View SourceReducing the impacts of grazing on water quality - EPA Victoria, accessed July 19, 2025,
View SourceLord Howe Island cattle comeback thanks to Macka's Angus Beef, accessed July 30, 2025,
View SourceManaging Cattle Grazing on Norfolk Island to Enhance Water Quality, accessed July 28, 2025,
View SourceMapping Australia's soil biodiversity - CSIRO, accessed August 9, 2025,
View SourceSoil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - Frontiers, accessed July 23, 2025
View SourceNorfolk Island Water Resource Assessment, accessed July 30, 2025,
View Source
Cattle : Norfolk Blue | RARE BREEDS TRUST OF AUSTRALIA | TidyHQ, accessed July 30, 2025,
View SourceSTOCK RESERVE - The Norfolk Islander, accessed July 30, 2025,
View SourceSoil Health & Your Wealth - presented by Graeme Sait - Regional Development Australia, accessed July 30, 2025,
View SourceRequirements for graziers | Environment, land and water | Queensland Government, accessed July 30, 2025,
View SourceResponse of Grazing Land Soil Health to Management Strategies: A Summary Review
View SourceThe science behind compost and soil health - DCCEEW, accessed July 30, 2025,
View SourceSoil and Landscape Grid of Australia - CSIRO, accessed July 30, 2025,
View SourceSoil and Landscape Grid of Australia - esoil.io, accessed July 26, 2025,
View SourceThe biogeography of relative abundance of soil fungi versus bacteria in surface topsoil, accessed August 1, 2025
View SourceFood System Mapping - Regional Development Australia - Mid North Coast NSW, accessed July 30, 2025,
View SourceFungal to Bacterial Ratios: What and Why? - Ward Laboratories, Inc., accessed July 30, 2025,
View SourceEN29 Lord Howe Island - Aotea Great Barrier Environmental Trust, accessed July 30, 2025,
View SourceMechanisms and implications of bacterial–fungal competition for soil resources - PMC, accessed July 30, 2025,
View SourceOvergrazing & Reducing Grazing Pressure | Bush Heritage Australia, accessed July 30, 2025,
View Source