Soil pH — Benchmark Detail

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 8 benchmarks together — the OptimalRange form drives the primary score, while 7 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MinimumOnly Guard OptimalRange Guard OptimalRange Guard LowerThreshold Guard UpperThreshold Guard OptimalRange Guard

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:

This benchmark defines the optimal soil pH range supporting healthy ecosystem function in protected natural areas of the biome.

Justification:

Defined by the interquartile range of pH values from the SLGA data for protected areas within the biome, capturing the central 50% of healthy ecosystem conditions.

Sources (1)

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

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

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

(PDF) The pH of Australian soils: field results from a national survey - ResearchGate, accessed July 25, 2025,

Direct Evidence Journal

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

View Source

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

Contextual Support

Soil and Landscape Grid of Australia - CSIRO, accessed August 1, 2025

View Source

The pH of Australian soils: field results from a national survey - CSIRO Publishing, accessed July 25, 2025,

Contextual Support Journal

The pH of Australian soils: field results from a national survey - CSIRO Publishing, accessed August 28, 2025,

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 24 Mar 2026

Notes

This range supports a healthy, functioning native ecosystem and reflects natural variability.

Related Benchmarks

Other benchmarks in the AUS-TSW-CON-SPH family.