Soil pH

AUS-AKW-AGR-SPH General High confidence

Benchmark Value

7.5 pH
Range: 6.5 to 8 pH
Thresholds: Lower: 6.5, Upper: 8.5
Optimal Range: 6.5 to 8
Direction: Higher is desirable ↑
Form: Point

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 Point Guard

Evidence & Context

A single value of pH(water) 7.5 is proposed as the benchmark.

Metric Definition:

Soil pH (water) as a measure of soil acidity or alkalinity affecting nutrient availability and ecosystem health in arid karstic calcareous soils.

Benchmark Definition:

This benchmark represents the optimal soil pH value for sustainable agricultural production in Australia's Arid Karstic Woodlands, balancing natural alkalinity with nutrient availability to support healthy soil biology and crop growth.

Justification:

The benchmark is derived by triangulating three key points: the natural state is highly alkaline (~pH 8.0–8.2), the optimal functional range for sustainable production is pH 6.5–8.0, and best-practice regenerative farmers actively manage towards the neutral end of this range (~pH 7.0) to maximize biological function and nutrient cycling.

Sources (2)

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

Soil pH - SA | Fact Sheets | soilquality.org.au, accessed July 30, 2025,

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Preview of Use of on-farm acidic sand to ameliorate calcareous-saline-alkaline heavy soils and improve plant available water - Grains Research and Development Corporation (GRDC)
Use of on-farm acidic sand to ameliorate calcareous-saline-alkaline heavy soils and improve plant available water - Grains Research and Development Corporation (GRDC) Journal

Use of on-farm acidic sand to ameliorate calcareous-saline-alkaline heavy soils and improve plant available water - Grains Research and Development Corporation (GRDC), accessed July 22, 2025

View Source

Supporting Sources (19)

Additional references from the underlying research that informed this benchmark.

Preview of Calcareous Soils Initiative - GRDC, accessed July 22, 2025,
Calcareous Soils Initiative - GRDC, accessed July 22, 2025,
Contextual Support Government

Calcareous Soils Initiative - GRDC, accessed July 24, 2025

View Source
Preview of Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed August 5, 2025,
Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed August 5, 2025,
Contextual Support GreyLiterature

The relationships between land management practices and soil condition and the quality of ecosystem services delivered from agri - DAFF

View Source
Preview of Distribution, characteristics and management of calcareous soils, accessed July 22, 2025
Distribution, characteristics and management of calcareous soils, accessed July 22, 2025
Contextual Support GreyLiterature

Distribution, characteristics and management of calcareous soils, accessed July 22, 2025

View Source
Preview of Eyre Peninsula Farming Systems Summary 2023 - Department of Primary Industries and Regions, accessed July 22, 2025,
Eyre Peninsula Farming Systems Summary 2023 - Department of Primary Industries and Regions, accessed July 22, 2025,
Contextual Support Government

Victorian Grain Cropping Soils - Calcarosols | VRO | Agriculture Victoria, accessed July 22, 2025

View Source
Preview of Managing Soil pH for Crop Production in Calcareous-Alkaline Soil - Issuu, accessed July 22, 2025
Managing Soil pH for Crop Production in Calcareous-Alkaline Soil - Issuu, accessed July 22, 2025
Contextual Support GreyLiterature

Managing Soil pH for Crop Production in Calcareous-Alkaline Soil - Issuu, accessed July 22, 2025

View Source
Preview of Nullarbor Plain - Wikipedia, accessed July 25, 2025,
Nullarbor Plain - Wikipedia, accessed July 25, 2025,
Contextual Support GreyLiterature

Nullarbor Plain - Wikipedia, accessed July 24, 2025

View Source
Preview of Overcoming constraints on highly calcareous soils | GroundCover - GRDC Ground Cover, accessed July 22, 2025
Overcoming constraints on highly calcareous soils | GroundCover - GRDC Ground Cover, accessed July 22, 2025
Contextual Support GreyLiterature

Overcoming constraints on highly calcareous soils | GroundCover - GRDC Ground Cover, accessed July 22, 2025

View Source
Preview of Regenerative Agriculture - Landscape SA, accessed July 6, 2025,
Regenerative Agriculture - Landscape SA, accessed July 6, 2025,
Contextual Support Government

Regenerative Agriculture - Local Land Services

View Source
Preview of Regenerative Agriculture Australia: Benefits and Practices - SONIC Natural Farming, accessed July 22, 2025,
Regenerative Agriculture Australia: Benefits and Practices - SONIC Natural Farming, accessed July 22, 2025,
Contextual Support GreyLiterature

More profitable crops on highly calcareous soils by improving early vigour and overcoming soil constraints | AIR EP, accessed July 22, 2025

View Source
Preview of Regenerative Agriculture Program restoring soil pH case study ..., accessed July 22, 2025
Regenerative Agriculture Program restoring soil pH case study ..., accessed July 22, 2025
Contextual Support GreyLiterature

Regenerative Agriculture Program restoring soil pH case study ..., accessed July 22, 2025

View Source
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 August 28, 2025,

View Source
Preview of Soil constraints project - an update on the economic response of long term soil amelioration strategies - GRDC, accessed July 22, 2025
Soil constraints project - an update on the economic response of long term soil amelioration strategies - GRDC, accessed July 22, 2025
Contextual Support Government

Soil constraints project - an update on the economic response of long term soil amelioration strategies - GRDC, accessed July 22, 2025

View Source
Preview of Soil Inorganic Carbon, the Other and Equally Important Soil Carbon Pool: Distribution, Controlling Factors, and the Impact of C, accessed July 26, 2025
Soil Inorganic Carbon, the Other and Equally Important Soil Carbon Pool: Distribution, Controlling Factors, and the Impact of C, accessed July 26, 2025
Contextual Support GreyLiterature

Overcoming soil constraints in highly calcareous soils – Soil CRC, accessed July 22, 2025

View Source
Preview of Soil organic matter in cropping systems - NSW Department of Primary Industries, accessed July 22, 2025,
Soil organic matter in cropping systems - NSW Department of Primary Industries, accessed July 22, 2025,
Contextual Support Journal

III. WORKING PAPERS - Food and Agriculture Organization of the United Nations, accessed July 26, 2025,

View Source
Preview of Soil pH - SA | Fact Sheets | soilquality.org.au, accessed July 22, 2025
Soil pH - SA | Fact Sheets | soilquality.org.au, accessed July 22, 2025
Contextual Support Journal

Soil pH - SA | Fact Sheets | soilquality.org.au, accessed July 22, 2025

View Source
Preview of Soil pH | Environment, land and water - Queensland Government, accessed July 22, 2025
Soil pH | Environment, land and water - Queensland Government, accessed July 22, 2025
Contextual Support GreyLiterature

Managing high-pH, calcareous and saline/sodic soils - Agronomy eUpdates, accessed July 22, 2025

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

Improving Soil Structure and pH Levels (DPIFM_NT) - Department of ..., accessed July 20, 2025

View Source
Preview of Taking the heat out of soil health | Landscape Boards SA, accessed July 22, 2025
Taking the heat out of soil health | Landscape Boards SA, accessed July 22, 2025
Contextual Support Government

Taking the heat out of soil health | Landscape Boards SA, accessed July 22, 2025

View Source
Preview of What are some possible explanations for the lack of vegetation on the Nullarbor Plain of Western Australia? - Quora, accessed July 27, 2025
What are some possible explanations for the lack of vegetation on the Nullarbor Plain of Western Australia? - Quora, accessed July 27, 2025
Contextual Support GreyLiterature

What are some possible explanations for the lack of vegetation on the Nullarbor Plain of Western Australia? - Quora, accessed July 22, 2025

View Source

Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Agricultural Crop Production
  • Assessment Conservation Target
  • Evidence Type TargetCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 24 Mar 2026

Notes

Lower Critical Threshold: 6.5 pH. Upper Detrimental Threshold: 8.5 pH. The optimal functional range is 6.5 to 8.0 pH, reflecting sustainable production conditions.