Soil pH — Benchmark Detail

Benchmark Value

5 pH (CaCl₂)

Direction: Higher is desirable ↑

Form: MinimumOnly

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.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard MaximumOnly Guard Point Guard MinimumOnly Guard OptimalRange Guard

Evidence & Context

Therefore, the Lower Critical Threshold for maintaining essential ecological function and preventing a shift into a persistent degraded state in this biome is defined as pH(CaCl2) 5.0.

Metric Definition:

Soil pH measured by the pHCaCl2 method, indicating the acidity level below which aluminium toxicity impairs ecosystem function.

Benchmark Definition:

This benchmark defines the lower critical soil pH threshold below which aluminium toxicity causes ecosystem degradation in Temperate Grassy Woodlands.

Justification:

This threshold is based on the onset of aluminium toxicity at pHCaCl2 5.0, which acts as a powerful ecological filter preventing growth of key native species.

Sources (1)

Preview of (PDF) Temperate Woodland Conservation and Management. - ResearchGate

(PDF) Temperate Woodland Conservation and Management. - ResearchGate GreyLiterature

Full article: Birds on farms: a review of factors influencing bird occurrence in the temperate woodlands of south-eastern Australia - Taylor & Francis Online, accessed May 17, 2025

View Source

Supporting Sources (10)

Additional references from the underlying research that informed this benchmark.

(PDF) Determining reference conditions for management and ..., accessed August 5, 2025,

Contextual Support Journal

Effects of Stock Grazing on Biodiversity Values in Temperate Native Grasslands and Grassy Woodlands in SE Australia: A Literature Review - ACT Government

View Source

(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.

View Source

Agriculture Victoria. (2024). Soil acidity.

Contextual Support Government

Agriculture Victoria. (2025). Soil acidity. Farm Management.

View Source

Australia's forests – overview - DAFF

Contextual Support

Approved Conservation Advice for the White Box - Yellow Box - Blakely's Red Gum Grassy Woodland and Derived Native Grassland - DCCEEW, accessed August 11, 2025,

View Source

Growing with Acid Soils - ecobotanica, accessed August 11, 2025,

Contextual Support

Growing with Acid Soils - ecobotanica, accessed August 11, 2025,

View Source

Preview of Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Contextual Support GreyLiterature

(PDF) Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 4, 2025,

View Source

Soil condition 2024 | NSW State of the Environment, accessed July 7, 2025,

Contextual Support Government

Soil pH | Environment, land and water - Queensland Government, accessed August 11, 2025,

View Source

Soil nutrient critical limits | MBFP | More Beef from Pastures - MLA, accessed May 13, 2025,

Contextual Support Government

Understanding soil tests for pastures | Soil | Farm management ..., accessed July 17, 2025

View Source

Soil pH - Wikipedia, accessed July 25, 2025,

Contextual Support GreyLiterature

Soil pH - Wikipedia, accessed August 11, 2025,

View Source

Soil Research - CSIRO PUBLISHING, accessed July 16, 2025,

Contextual Support Journal

Soil Research - CSIRO PUBLISHING, accessed August 11, 2025,

View Source

Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Vegetation Woodland
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 9 Jun 2026

Notes

Soil pH values below this level indicate significant ecosystem compromise and a persistent degraded state. No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

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