Soil pH

AUS-ASP-AGR-SPH General Moderate confidence

Benchmark Value

No specific value — see range
Range: 6.5 to 7 pH (CaCl₂)
Optimal Range: 6.5 to 7
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 OptimalRange Guard MinimumOnly Guard MaximumOnly Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard OptimalRange Guard

Evidence & Context

Based on the synthesis of the optimal functional range and the tangible outcomes observed in the Macdonald farm case study, the benchmark for the 'best available condition' is a narrow range centered on neutral. This range sits squarely within the scientifically defined optimal zone for nutrient availability and microbial function, effectively avoids the constraints of both acidity and alkalinity, and aligns with the demonstrated target of a successful, real-world regenerative farming system.

Metric Definition:

Soil pH as measured by the CaCl2 method (pHCaCl2​​) representing the active chemical environment influencing nutrient availability and microbial activity in soil.

Benchmark Definition:

This benchmark represents the actively managed target pH range in a successful regenerative cropping system in Australia's Arid Shrublands & Stony Plains biome, reflecting optimal nutrient availability and microbial activity.

Justification:

This benchmark is supported by broader scientific literature defining the optimal range for soil health and the documented outcomes of the Macdonald farm case study demonstrating high ecological function at near-neutral pH.

Sources (1)

Preview of The relationships between land management practices and soil condition and the quality of ecosystem services delivered from agri - DAFF, accessed August 4, 2025,
The relationships between land management practices and soil condition and the quality of ecosystem services delivered from agri - DAFF, accessed August 4, 2025, Journal

Regenerative Agriculture Program restoring soil pH case study ..., accessed August 28, 2025

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Supporting Sources (23)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) The pH of Australian soils: field results from a national survey - ResearchGate, accessed July 25, 2025,
(PDF) The pH of Australian soils: field results from a national survey - ResearchGate, accessed July 25, 2025,
Contextual Support 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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Preview of A review of the economics of regenerative agriculture in Western Australia - DPIRD's Digital library, accessed August 4, 2025
A review of the economics of regenerative agriculture in Western Australia - DPIRD's Digital library, accessed August 4, 2025
Contextual Support Journal

A review of the economics of regenerative agriculture in Western Australia - DPIRD's Digital library

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Preview of Agriculture Victoria. (2024). Soil acidity.
Agriculture Victoria. (2024). Soil acidity.
Contextual Support Government

Agriculture Victoria. (2025). Soil acidity. Farm Management.

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Preview of Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,
Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,
Contextual Support Journal

How should we manage our soils to increase soil carbon?, accessed May 10, 2026

View Source
Preview of Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 16, 2025
Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 16, 2025
Contextual Support Journal

Soil Health: Supporting Rural Industries in the Wet Tropics, accessed August 28, 2025

View Source
Preview of Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 22, 2025,
Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 22, 2025,
Contextual Support Government

Regenerative ... - Landscape South Australia - Eyre Peninsula, accessed August 28, 2025

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Preview of Impacts of Agricultural Management Practices on Soil Health - NCBI, accessed May 11, 2025
Impacts of Agricultural Management Practices on Soil Health - NCBI, accessed May 11, 2025
Contextual Support

Impacts of Agricultural Management Practices on Soil Health - NCBI, accessed August 28, 2025

View Source
Preview of Land | State of the Environment Report 2011
Land | State of the Environment Report 2011
Contextual Support Journal

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 28, 2025

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Preview of Liming acidic soils creates profits, land use options but often more emissions - CSIRO Publishing
Liming acidic soils creates profits, land use options but often more emissions - CSIRO Publishing
Contextual Support Journal

Liming acidic soils creates profits, land use options but often more emissions - CSIRO Publishing

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Preview of Mapping and describing your natural resources - MBFP-Pastoral, accessed August 10, 2025
Mapping and describing your natural resources - MBFP-Pastoral, accessed August 10, 2025
Contextual Support GreyLiterature

soils and landscapes of mulga lands with special reference to south western queensland, accessed August 28, 2025

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Preview of Mapping the impact of subsoil constraints on soil available water capacity and potential crop yield - CSIRO Publishing, accessed July 30, 2025
Mapping the impact of subsoil constraints on soil available water capacity and potential crop yield - CSIRO Publishing, accessed July 30, 2025
Contextual Support Journal

Mapping the impact of subsoil constraints on soil available water capacity and potential crop yield - CSIRO Publishing, accessed August 28, 2025

View Source
Preview of NVIS Fact sheet MVG 14 – Mallee woodlands and shrublands - DCCEEW, accessed July 15, 2025
NVIS Fact sheet MVG 14 – Mallee woodlands and shrublands - DCCEEW, accessed July 15, 2025
Contextual Support Journal

NVIS Fact sheet MVG 14 – Mallee woodlands and shrublands - DCCEEW, accessed August 28, 2025

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Preview of NVIS Fact sheet MVG 19 6 Tussock grasslands, accessed July 16, 2025,
NVIS Fact sheet MVG 19 6 Tussock grasslands, accessed July 16, 2025,
Contextual Support Journal

Understanding soil pH, accessed August 28, 2025

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Preview of Pastures and acid soils - NSW Government
Pastures and acid soils - NSW Government
Contextual Support Journal

pH in Soil and Nutrient Availability - Australian Scientific Pty Ltd - Water Quality Division, accessed August 28, 2025

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Preview of Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed August 5, 2025,
Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed August 5, 2025,
Contextual Support Journal

Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed July 20, 2025,

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

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

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Preview of Soil-landscapes of Western Australia's rangelands and arid interior - SciSpace, accessed August 28, 2025,
Soil-landscapes of Western Australia's rangelands and arid interior - SciSpace, accessed August 28, 2025,
Contextual Support Journal

Soil-landscapes of Western Australia's rangelands and arid interior - SciSpace, accessed August 28, 2025

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Preview of SoilQuality.org.au. (n.d.). Soil Acidity Factsheet.
SoilQuality.org.au. (n.d.). Soil Acidity Factsheet.
Contextual Support

Soil Acidity | Fact Sheets | soilquality.org.au, accessed July 20, 2025,

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Preview of State Soils - Soil Science Australia, accessed August 28, 2025,
State Soils - Soil Science Australia, accessed August 28, 2025,
Contextual Support Journal

State Soils - Soil Science Australia, accessed August 28, 2025

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Preview of Sustainable Practices for Enhancing Soil Health and Crop Quality in Modern Agriculture: A Review - MDPI, accessed August 28, 2025,
Sustainable Practices for Enhancing Soil Health and Crop Quality in Modern Agriculture: A Review - MDPI, accessed August 28, 2025,
Contextual Support Journal

Sustainable Practices for Enhancing Soil Health and Crop Quality in Modern Agriculture: A Review - MDPI, accessed August 28, 2025

View Source
Preview of The extent of surface soil acidity in the relatively intensive... | Download Table - ResearchGate, accessed July 28, 2025
The extent of surface soil acidity in the relatively intensive... | Download Table - ResearchGate, accessed July 28, 2025
Contextual Support

Agricultural production system in arid and semi-arid regions, accessed August 28, 2025

View Source
Preview of The pH of Australian soils: field results from a national survey - CSIRO Publishing, accessed July 25, 2025,
The pH of Australian soils: field results from a national survey - CSIRO Publishing, accessed July 25, 2025,
Contextual Support Journal

Soil pH Explained - Soil Quality Knowledge Base

View Source
Preview of Tool 6.7 Soil health benchmarks and guidelines for managing problem soils, accessed August 28, 2025,
Tool 6.7 Soil health benchmarks and guidelines for managing problem soils, accessed August 28, 2025,
Contextual Support GreyLiterature

NVIS Fact sheet MVG 19 – Tussock grasslands, accessed August 28, 2025

View Source

Context

  • Region Australia
  • Biome Arid Shrublands & Stony Plains
  • Land Use Agricultural Crop Production
  • Assessment Not Stated
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 10 Jun 2026

Notes

Lower Critical Threshold: 4.8 pH (CaCl₂). Upper Detrimental Threshold: 8.3 pH (CaCl₂). Managing the topsoil to a near-neutral pH eliminated aluminium toxicity, enhanced legume nitrogen fixation, and stabilized nutrient availability. The upper detrimental threshold is associated with sodicity and severe nutrient deficiencies. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.