Soil pH — Benchmark Detail - Nature Index

Benchmark Value

No specific value — see range

Range: 6.5 to 7 pH

Thresholds: Lower: 4.8, Upper: 8

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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard LowerThreshold Guard UpperThreshold Guard OptimalRange Guard OptimalRange Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard UpperThreshold 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 ($pH_{CaCl_2}$) in topsoil (0-10 cm) of agricultural cropping systems.

Benchmark Definition:

This benchmark represents the optimal soil pH range measured by the calcium chloride method for agricultural cropping systems in Australia's Temperate Semi-Arid Shrublands & Open Woodlands, indicating the best available condition for soil health and nutrient cycling.

Justification:

This benchmark is justified not merely as an optimal chemical state but as a measurable indicator of a superior management intent. It represents a holistic, whole-profile approach to building long-term ecological resilience, supported by a verifiable 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 Land Management - HEALTHY SOILS AUSTRALIA

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

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

Chapter 5 - Victorian Resources Online, 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

Soil pH in northern and southern areas of the WA wheatbelt - DPIRD's Digital library, accessed July 7, 2025,

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

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

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, accessed July 12, 2025,

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

Soil Acidity in the Mallee - Department for Environment and Water, accessed July 7, 2025,

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 pH and Microbial Life - Number Analytics, accessed July 7, 2025,

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

Soil acidity and liming. 4th edition 2021 - NSW Department of ..., accessed July 7, 2025,

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 - SA | Fact Sheets | soilquality.org.au

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

Contextual Support Government

Soil pH - SA | Fact Sheets | soilquality.org.au, accessed July 30, 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 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

Working with bio-amendments: Insights from cropping farmers - Soils For Life, accessed July 7, 2025,

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

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 Pristine Reference
Evidence Type TargetCondition

Lifecycle

Status Active
Version 1
Effective From 24 Mar 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.