Soil pH

AUS-TSW-CON-SPH General High confidence

Benchmark Value

No specific value — see range
Range: 6.8 to 8.2 pH
Optimal Range: 6.8 to 8.2
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 6 benchmarks together — the OptimalRange form drives the primary score, while 5 guard(s) constrain the result.

Evidence & Context

The Optimal Range for overall ecosystem health, representing the interquartile range of reference sites, is approximately pH(water) 6.8 to 8.2.

Metric Definition:

Soil pH measured in a 1:5 soil-to-water solution (pHw) in the topsoil layer (0-10 cm).

Benchmark Definition:

Interquartile range of soil pH values from reference conservation sites representing optimal ecosystem health.

Justification:

Defined by the central 50% of pH values from the Soil and Landscape Grid of Australia data for protected natural areas.

Sources (1)

Preview of Soil and Landscape Grid of Australia - CSIRO, accessed July 30, 2025,
Soil and Landscape Grid of Australia - CSIRO, accessed July 30, 2025, Government

Soil and Landscape Grid of Australia - CSIRO

View Source

Supporting Sources (4)

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,
Direct Evidence Journal

Caritat, P. de, & Cooper, M. (2011). The pH of Australian soils: Field results from a national survey. Soil Research, 49, 172-182.

View Source
Preview of Soil and Landscape Grid National Soil Attribute Maps - pH (Water) (3" resolution) - Release 1. v2
Soil and Landscape Grid National Soil Attribute Maps - pH (Water) (3" resolution) - Release 1. v2
Methodology Source Government

Soil and Landscape Grid National Soil Attribute Maps - pH (Water) (3" resolution) - Release 1. v2

View Source
Preview of Soil and Landscape Grid of Australia - CSIRO
Soil and Landscape Grid of Australia - CSIRO
Direct Evidence Government

Soil and Landscape Grid National Soil Attribute Maps - pH - Calcium Chloride (3" resolution) - Release 2 - TERN Data Discovery Portal

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

Context

  • Region Australia
  • Biome Temperate Semi-Arid Shrublands & Open Woodlands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type HealthyOperationalRange

Lifecycle

  • Status Active
  • Version 1
  • Effective From 9 Jun 2026

Notes

This range captures the natural variability and conditions under which native ecosystems demonstrably thrive.