Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 7.5 to 9 pH

Optimal Range: 7.5 to 9

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

A representative range for the topsoil in a healthy, natural state is pH 7.5 – 9.0.

Metric Definition:

Soil pH range for Calcarosols topsoil in natural, healthy condition.

Benchmark Definition:

This benchmark represents the natural pH range for Calcarosols topsoil in healthy arid inland floodplain ecosystems.

Justification:

Based on published literature and soil profile data consistently placing Calcarosols in the alkaline range.

Sources (2)

Preview of Australian Soil Classification edition 3 - CALCAROSOLS

Australian Soil Classification edition 3 - CALCAROSOLS Government

Monitoring changes in soil salinity and sodicity to depth, at a ...

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Preview of Soil pH - SA | Fact Sheets | soilquality.org.au

Soil pH - SA | Fact Sheets | soilquality.org.au Government

Soil Acidity - NSW | Fact Sheets | soilquality.org.au

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Supporting Sources (10)

Additional references from the underlying research that informed this benchmark.

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

Direct Evidence Journal

Caritat, P. de, & Cooper, M. (2011). The pH of Australian soils: Field results from a national survey. Soil Research, 49, 172-182.

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ASC - VERTOSOLS - Soil Science Australia

Contextual Support

What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase

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AusEarthed. (n.d.). Soil Reading.

Contextual Support Journal

Victorian Resources Online | Resources | Support and resources ..., accessed July 21, 2025,

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Ecological impacts of flood mitigation and drainage in coastal lowlands - AustLII

Contextual Support

Ecological impacts of flood mitigation and drainage in coastal lowlands - AustLII, accessed July 21, 2025,

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Government of South Australia, Department for Environment and Water. (n.d.). Soil Health and Condition.

Contextual Support Government

Soil acidity - Department for Environment and Water

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National Guidance on Acid Sulfate Soils - Water Quality Australia

Contextual Support Journal

Managing soils - Department of Primary Industries and Regional Development, accessed July 17, 2025

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Soil Constraints in an Arid Environment - Encyclopedia.pub

Contextual Support GreyLiterature

Soil Constraints in an Arid Environment - Encyclopedia.pub, accessed July 27, 2025

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Victorian Resources Online | Resources | Support and resources ...

Contextual Support Government

Structural controls on the orientation of erosion gullies in mid-western New South Wales, Australia, accessed July 22, 2025

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Water and sediment quality in the Diamantina-Georgina River ..., accessed July 21, 2025,

Contextual Support Journal

Water and sediment quality in the Diamantina-Georgina River ..., accessed July 21, 2025,

View Source

Water and sediment quality in the Diamantina-Georgina River catchment, Lake Eyre Basin

Direct Evidence Journal

Water quality in the Georgina-Diamantina River catchment

View Source

Context

Region Australia
Biome Arid Inland Floodplains & Ephemeral River Systems
Land Use Conservation / Protected Natural Areas
Assessment Pristine Reference
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 3 Jun 2026

Notes

Reflects the high carbonate content and natural alkalinity of Calcarosols.

Related Benchmarks

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