Soil pH — Benchmark Detail - Nature Index

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 2 benchmarks together — the OptimalRange form drives the primary score, while 1 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard

Evidence & Context

Therefore, the reference value for the best available condition of soil pH in agricultural cropping systems within Australia's Temperate Semi-Arid Shrublands & Open Woodlands is proposed as a narrow range of $pH_{CaCl_2}$ 6.5 - 7.0.

Metric Definition:

Soil pH measured using the calcium chloride method ($pH_{CaCl_2}$), standard for scientific and agricultural assessment in Australia.

Benchmark Definition:

This benchmark defines the optimal soil pH range measured by the calcium chloride method for healthy soil conditions in agricultural cropping systems within Australia's Temperate Semi-Arid Shrublands & Open Woodlands biome.

Justification:

This benchmark is justified not merely as an optimal chemical state but as a measurable indicator of a superior management intent, supported by a real-world regenerative agriculture case study and consensus from state agencies and scientific literature.

Sources (3)

Preview of Regenerative Agriculture - a literature review on the practices and mechanisms used to improve soil health - DPIRD's Digital library, accessed August 5, 2025,

Regenerative Agriculture - a literature review on the practices and mechanisms used to improve soil health - DPIRD's Digital library, accessed August 5, 2025,

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

Preview of Soil acidity - its stratification and amelioration with lime - GRDC

Soil acidity - its stratification and amelioration with lime - GRDC Government

Soil acidity - its stratification and amelioration with lime - GRDC

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

Supporting Sources (18)

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.

Preview of Great Western Woodlands - Wikipedia, accessed July 10, 2025,

Great Western Woodlands - Wikipedia, accessed July 10, 2025,

Contextual Support GreyLiterature

Great Western Woodlands - Wikipedia

Preview of Healthy soils Compost trial, Aburn Park farm, The Lakes - Waste Authority WA, accessed July 7, 2025,

Healthy soils Compost trial, Aburn Park farm, The Lakes - Waste Authority WA, accessed July 7, 2025,

Contextual Support Journal

Healthy soils Compost trial, Aburn Park farm, The Lakes - Waste Authority WA, accessed July 7, 2025,

Preview of Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe, accessed July 10, 2025,

Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe, accessed July 10, 2025,

Contextual Support Journal

Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe

Preview of Soil acidification | Meat & Livestock Australia - MLA, accessed July 7, 2025,

Soil acidification | Meat & Livestock Australia - MLA, accessed July 7, 2025,

Contextual Support Journal

Soil acidification | Meat & Livestock Australia - MLA, accessed July 7, 2025,

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

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

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

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

Contextual Support Government

Soil acidity and liming 4th edition - NSW Department of Primary Industries, accessed July 7, 2025,

Preview of Soil pH | Agriculture and Food, accessed July 7, 2025,

Soil pH | Agriculture and Food, accessed July 7, 2025,

Contextual Support Government

Soil pH | Agriculture and Food, accessed July 7, 2025,

Preview of Soil pH Explained - Soil Quality Knowledge Base, accessed July 7, 2025,

Soil pH Explained - Soil Quality Knowledge Base, accessed July 7, 2025,

Contextual Support Journal

FARMING IN AN ANCIENT LAND – AUSTRALIA'S JOURNEY TOWARDS SUSTAINABLE AGRICULTURE. - NSERL, accessed July 7, 2025,

Preview of Soil pH in northern and southern areas of the WA wheatbelt - DPIRD's Digital library

Soil pH in northern and southern areas of the WA wheatbelt - DPIRD's Digital library

Direct Evidence

DPIRD WA / Wheatbelt Study

Preview of Soil pH in the microbial world - EnviroStraw, accessed July 7, 2025,

Soil pH in the microbial world - EnviroStraw, accessed July 7, 2025,

Contextual Support GreyLiterature

Soil pH in the microbial world - EnviroStraw, accessed July 7, 2025,

Preview of Soil Quality Knowledge Base. (n.d.). Soil pH.

Soil Quality Knowledge Base. (n.d.). Soil pH.

Contextual Support GreyLiterature

Soil Quality Knowledge Base. (n.d.). Soil pH.

Preview of Soil salinity: A serious environmental issue and plant growth promoting bacteria as one of the tools for its alleviation - PubMed Central, accessed July 7, 2025,

Soil salinity: A serious environmental issue and plant growth promoting bacteria as one of the tools for its alleviation - PubMed Central, accessed July 7, 2025,

Contextual Support GreyLiterature

Relationship between soil pH and concentration of hydrogen ions and aluminium - YouTube, accessed July 7, 2025,

Preview of Southeast Australia temperate savanna - Wikipedia, accessed August 4, 2025

Southeast Australia temperate savanna - Wikipedia, accessed August 4, 2025

Contextual Support GreyLiterature

Southeast Australia temperate savanna - Wikipedia

Preview of Starting / Enhancing Your Regenerative Agriculture Journey

Starting / Enhancing Your Regenerative Agriculture Journey

Contextual Support Journal

Starting / Enhancing Your Regenerative Agriculture Journey, accessed July 7, 2025,

Preview of Starting / Enhancing Your Regenerative Agriculture Journey, accessed July 18, 2025,

Starting / Enhancing Your Regenerative Agriculture Journey, accessed July 18, 2025,

Contextual Support GreyLiterature

Regenerative Agriculture - a literature review on the practices and mechanisms used to improve soil health, accessed July 7, 2025,

Preview of Understanding soil tests for pastures | Soil | Farm management ..., accessed July 7, 2025,

Understanding soil tests for pastures | Soil | Farm management ..., accessed July 7, 2025,

Contextual Support Government

Soil Acidity | Fact Sheets | soilquality.org.au, accessed July 16, 2025,

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Agricultural Crop Production
Assessment Conservation Target
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 9 Jun 2026

Notes

Lower Critical Threshold: 4.8 pH (CaCl₂). Upper Detrimental Threshold: 8 pH (CaCl₂). The benchmark indicates a system actively managed for optimal biological function and nutrient cycling, moving beyond conventional targets aimed merely at avoiding immediate constraints.