Soil pH

AUS-TGP-AGR-SPH General Moderate confidence

Benchmark Value

No specific value — see range
Range: 5.5 to 7 pH
Optimal Range: 5.5 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

a clear consensus emerges for an optimal topsoil range of approximately pH(CaCl₂) 5.5 to 7.0.

Metric Definition:

Soil pH measured in 0.01 M calcium chloride solution

Benchmark Definition:

This benchmark defines the optimal soil pH range in temperate Australian agricultural crop production soils, where soil chemistry and biology are balanced to maximize nutrient availability and support healthy crop growth.

Justification:

This range represents a 'sweet spot' where the complex interplay of soil chemistry and biology is balanced to maximize nutrient availability, minimize elemental toxicities, and foster a thriving soil food web.

Sources (1)

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

View Source

Supporting Sources (32)

Additional references from the underlying research that informed this benchmark.

Preview of Agriculture study on zinc nanofertilsers - ANSTO
Agriculture study on zinc nanofertilsers - ANSTO
Contextual Support Government

Improving Structure and pH Levels in Top End Soils for Horticulture - Department of Agriculture and Fisheries

View Source
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 Aluminium toxicity - Enviro Data SA
Aluminium toxicity - Enviro Data SA
Contextual Support Journal

Aluminium toxicity - Enviro Data SA

View Source
Preview of Aluminum stress signaling in plants - PMC - PubMed Central
Aluminum stress signaling in plants - PMC - PubMed Central
Contextual Support Journal

Aluminum stress signaling in plants - PMC - PubMed Central

View Source
Preview of Chemical characteristics of phosphorus in alkaline soils from southern Australia | Request PDF - ResearchGate
Chemical characteristics of phosphorus in alkaline soils from southern Australia | Request PDF - ResearchGate
Contextual Support Journal

AGRITOPIC March 2022 1. INTRODUCTION 2. ZINC IN SOILS - Incitec Pivot Fertilisers

View Source
Preview of How do I manage acidic soils? - NSW Department of Primary Industries
How do I manage acidic soils? - NSW Department of Primary Industries
Contextual Support

How do I manage acidic soils? - NSW Department of Primary Industries

View Source
Preview of How to Identify and Treat Alkaline Soil in Your Farmland | AgNote
How to Identify and Treat Alkaline Soil in Your Farmland | AgNote
Contextual Support GreyLiterature

How to Identify and Treat Alkaline Soil in Your Farmland | AgNote

View Source
Preview of Importance of Mineral Nutrition for Mitigating Aluminum Toxicity in Plants on Acidic Soils: Current Status and Opportunities - MDPI
Importance of Mineral Nutrition for Mitigating Aluminum Toxicity in Plants on Acidic Soils: Current Status and Opportunities - MDPI
Contextual Support Journal

Aluminum in plant: Benefits, toxicity and tolerance mechanisms - PMC - PubMed Central

View Source
Preview of Investigating the impacts of groundwater on soil properties and ..., accessed July 28, 2025
Investigating the impacts of groundwater on soil properties and ..., accessed July 28, 2025
Contextual Support Journal

Soil acidity and liming 4th edition - NSW Department of Primary Industries

View Source
Preview of IRON DEFICIENCY (High pH Level) - Ross Roses
IRON DEFICIENCY (High pH Level) - Ross Roses
Contextual Support Government

IRON DEFICIENCY (High pH Level) - Ross Roses

View Source
Preview of Iron Deficiency in the Garden
Iron Deficiency in the Garden
Contextual Support Journal

Nutrients | Insects and Organic Gardening

View Source
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

View Source
Preview of Manganese (Mn) Toxicity
Manganese (Mn) Toxicity
Contextual Support Journal

Manganese (Mn) Toxicity

View Source
Preview of Manganese in Plants: From Acquisition to Subcellular Allocation - Frontiers
Manganese in Plants: From Acquisition to Subcellular Allocation - Frontiers
Contextual Support

Manganese in Plants: From Acquisition to Subcellular Allocation - Frontiers

View Source
Preview of MANGANESE TOXICITY IN AN ACID SOIL.
MANGANESE TOXICITY IN AN ACID SOIL.
Contextual Support Journal

MANGANESE TOXICITY IN AN ACID SOIL.

View Source
Preview of NSW Department of Primary Industries. (2021). Soil Acidity and Liming (AC.19).
NSW Department of Primary Industries. (2021). Soil Acidity and Liming (AC.19).
Contextual Support Government

Understanding soil pH

View Source
Preview of Optimal lime rates for soil acidity mitigation: impacts of crop choice and nitrogen fertiliser in Western Australia - CSIRO Publishing
Optimal lime rates for soil acidity mitigation: impacts of crop choice and nitrogen fertiliser in Western Australia - CSIRO Publishing
Contextual Support Government

Micronutrient Deficiencies in Australian Field Crops - GOV.UK

View Source
Preview of Optimal lime rates for soil acidity mitigation: impacts of crop choice and nitrogen fertilizer in Western Australia
Optimal lime rates for soil acidity mitigation: impacts of crop choice and nitrogen fertilizer in Western Australia
Methodology Source Government

Optimal lime rates for soil acidity mitigation: impacts of crop choice and nitrogen fertilizer in Western Australia

View Source
Preview of pH, Measurement of pH in Soil - Bacto Laboratories Pty Ltd
pH, Measurement of pH in Soil - Bacto Laboratories Pty Ltd
Methodology Source GreyLiterature

pH, Measurement of pH in Soil - Bacto Laboratories Pty Ltd

View Source
Preview of Plant Nutrition and Trace Elements | MFC - Australian Organic Registered Farm Input
Plant Nutrition and Trace Elements | MFC - Australian Organic Registered Farm Input
Contextual Support GreyLiterature

Plant Nutrition and Trace Elements | MFC - Australian Organic Registered Farm Input

View Source
Preview of Regenerative agriculture - Wikipedia, accessed August 8, 2025
Regenerative agriculture - Wikipedia, accessed August 8, 2025
Contextual Support

Regenerative agriculture - Wikipedia

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Preview of Soil Acidity - Ag Excellence Alliance, accessed July 10, 2025,
Soil Acidity - Ag Excellence Alliance, accessed July 10, 2025,
Contextual Support GreyLiterature

Soil Health - Dairy Australia

View Source
Preview of Soil Acidity - NSW | Fact Sheets | soilquality.org.au, accessed on May 31, 2025
Soil Acidity - NSW | Fact Sheets | soilquality.org.au, accessed on May 31, 2025
Contextual Support Government

Managing soils - Department of Primary Industries and Regional Development

View Source
Preview of Soil acidity and liming - Holbrook Landcare Network
Soil acidity and liming - Holbrook Landcare Network
Contextual Support GreyLiterature

Soil acidity and liming - Holbrook Landcare Network

View Source
Preview of Soil Carbon Forward Plan DEW/PIRSA/Landscape South Australia - Enviro Data SA
Soil Carbon Forward Plan DEW/PIRSA/Landscape South Australia - Enviro Data SA
Contextual Support Journal

Regenerative Agriculture—A Literature Review on the Practices and ...

View Source
Preview of Soil pH | Environment, land and water - Queensland Government
Soil pH | Environment, land and water - Queensland Government
Contextual Support Journal

Micronutrient Deficiencies in Australian Field Crops - ResearchGate

View Source
Preview of Soil pH | Environment, land and water - Queensland Government, accessed July 30, 2025,
Soil pH | Environment, land and water - Queensland Government, accessed July 30, 2025,
Contextual Support Government

Australian dryland soils are acidic and nutrient‐depleted, and have unique microbial communities compared with other drylands - Arid Ecology Lab

View Source
Preview of The Biogeography of Soil Bacteria in Australia Exhibits Greater ...
The Biogeography of Soil Bacteria in Australia Exhibits Greater ...
Contextual Support Journal

Soil acidification | .Meat & Livestock Australia

View Source
Preview of The future of managing acidic soils - Landscape SA
The future of managing acidic soils - Landscape SA
Direct Evidence Government

Regenerative Agriculture Program restoring soil pH case study: Macdonald, Whites Flat/Koppio

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 What is my optimum soil pH?
What is my optimum soil pH?
Contextual Support Journal

SOIL SMART: UNDERSTANDING YOUR SOILS - Department for Environment and Water

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Preview of Why phosphorus is important - NSW Department of Primary Industries, accessed August 4, 2025
Why phosphorus is important - NSW Department of Primary Industries, accessed August 4, 2025
Contextual Support Government

Why phosphorus is important - NSW Department of Primary Industries

View Source

Context

  • Region Australia
  • Biome Temperate Grassy Woodlands & Plains
  • Land Use Agricultural Crop Production
  • Assessment Not Stated
  • Evidence Type ReferenceCondition

Lifecycle

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

Notes

Validated as the core operational target for achieving high productivity and robust ecological health in most temperate Australian agricultural systems. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.