Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 5.5 to 6.5 pH

Thresholds: Lower: 5, Upper: 7

Optimal Range: 5.5 to 6.5

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 8 benchmarks together — the OptimalRange form drives the primary score, while 7 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MinimumOnly Guard OptimalRange Guard OptimalRange Guard LowerThreshold Guard UpperThreshold Guard OptimalRange Guard

Evidence & Context

Based on this synthesis, the benchmark representing the best available condition for a conservation-managed Temperate Grassy Woodland is a moderately to slightly acidic soil within the range of pH(CaCl2) 5.5 to 6.5.

Metric Definition:

Soil pH measured in a slurry of soil and 0.01 M calcium chloride (pHCaCl2)

Benchmark Definition:

This benchmark represents the optimal soil pH range for conservation-managed Temperate Grassy Woodlands, indicating moderately to slightly acidic conditions that support native plant communities and ecosystem health.

Justification:

The benchmark range represents the optimal moderately to slightly acidic conditions found in high-integrity, little-grazed remnant temperate grassy woodlands. It is safely above the toxicity thresholds, aligns with the known requirements of the native plant community, and is consistent with the conditions found in the highest-quality remnant sites.

Sources (1)

Preview of (PDF) Temperate Woodland Conservation and Management. - ResearchGate

(PDF) Temperate Woodland Conservation and Management. - ResearchGate GreyLiterature

(PDF) Determining reference conditions for management and ..., accessed August 11, 2025,

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Supporting Sources (10)

Additional references from the underlying research that informed this benchmark.

(PDF) Determining reference conditions for management and ..., accessed August 5, 2025,

Contextual Support

(PDF) Impacts of tree invasion on floristic composition of subtropical grasslands on the Bunya Mountains, Australia - ResearchGate, accessed May 19, 2025

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(PDF) The pH of Australian soils: field results from a national survey - ResearchGate, accessed July 25, 2025,

Contextual Support Journal

Soil pH | Environment, land and water - Queensland Government, accessed August 28, 2025,

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Agriculture Victoria. (2024). Soil acidity.

Contextual Support

Soil acidity | Soil | Farm management - Agriculture Victoria, accessed August 28, 2025

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Australia's forests – overview - DAFF

Contextual Support

AUSTRALIA'S STATE OF THE FORESTS REPORT - DAFF, accessed August 28, 2025,

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Growing with Acid Soils - ecobotanica, accessed August 11, 2025,

Contextual Support

Growing with Acid Soils - ecobotanica, accessed August 11, 2025,

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Preview of Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Contextual Support Journal

(PDF) Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 4, 2025,

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Soil condition 2024 | NSW State of the Environment, accessed July 7, 2025,

Contextual Support Government

Soil pH | Environment, land and water - Queensland Government, accessed August 11, 2025,

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Soil nutrient critical limits | MBFP | More Beef from Pastures - MLA, accessed May 13, 2025,

Contextual Support GreyLiterature

Understanding soil tests for pastures | Soil | Farm management ..., accessed July 17, 2025,

View Source

Soil pH - Wikipedia, accessed July 25, 2025,

Contextual Support GreyLiterature

Soil pH - Wikipedia, accessed August 11, 2025,

View Source

Soil Research - CSIRO PUBLISHING, accessed July 16, 2025,

Contextual Support Journal

Soil Research - CSIRO PUBLISHING, accessed August 11, 2025,

View Source

Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Vegetation Woodland
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

Lower Critical Threshold: A threshold is identified at pH(CaCl2) 5.0. Below this level, soil becomes significantly compromised due to aluminium toxicity, which acts as a powerful ecological filter, preventing the growth of many key native species and locking the ecosystem in a degraded state. Upper Boundary: While no sharp detrimental threshold exists, pH values exceeding 7.0 are considered increasingly sub-optimal due to nutrient availability issues.

Related Benchmarks

Other benchmarks in the AUS-TGP-CON-SPH family.