Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 6.9 to 7.8 pH

Thresholds: Lower: 5.5, Upper: 8

Optimal Range: 6.9 to 7.8

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 19 benchmarks together — the OptimalRange form drives the primary score, while 18 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The selected reference value is the range pH 6.9 – 7.8 (measured in 0.01M CaCl2).

Metric Definition:

Soil pH measured in 0.01M CaCl2 solution

Benchmark Definition:

This benchmark represents the optimal soil pH range measured in 0.01M CaCl2 solution for Temperate Semi-Arid Shrublands & Open Woodlands under livestock grazing and pasture. It reflects the highest achievable soil condition in managed agricultural systems supported by regenerative grazing and corroborated by high-integrity reference sites.

Justification:

This range is directly supported by field measurements from multiple properties implementing best-practice regenerative grazing, representing the highest achievable condition in a managed agricultural system, and corroborated by data from other high-integrity sites.

Sources (3)

Preview of Effects of soil pH on the growth, soil nutrient composition, and rhizosphere microbiome of Ageratina adenophora - PMC - PubMed Central, accessed July 30, 2025,

Effects of soil pH on the growth, soil nutrient composition, and rhizosphere microbiome of Ageratina adenophora - PMC - PubMed Central, accessed July 30, 2025, Journal

Factors influencing decline in soil pH in Hawaiian Eucalyptus and Albizia plantations

View Source

Preview of Soil | Australia state of the environment 2021, accessed August 12, 2025,

Soil | Australia state of the environment 2021, accessed August 12, 2025, Journal

OzFlux-TERN GWW SuperSite presentation: Soil Chemical Properties

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, Government

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

View Source

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

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,

View Source

NSW Environment Protection Authority. (2021). State of the Environment - Soil Condition 2021.

Contextual Support Government

Soil Acidity | Meat & Livestock Australia, accessed July 10, 2025,

View Source

Soil Acidity - Ag Excellence Alliance, accessed July 10, 2025,

Contextual Support GreyLiterature

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

View Source

SoilQuality.org.au. (n.d.). Soil Acidity Factsheet.

Contextual Support

Soil Acidity | Fact Sheets | soilquality.org.au, accessed August 28, 2025,

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Livestock Grazing & Pasture
Assessment Pristine Reference
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

Lower Critical Threshold: 5.5 pH. Upper Detrimental Threshold: 8 pH. The optimal range avoids detrimental effects of acidity below pH 5.5 and alkalinity above pH 8.0, reflecting a naturally neutral-to-alkaline status of many soils in this biome. Excessive pH above 8.0-8.5 can cause micronutrient deficiencies and indicate degradation from overgrazing.

Related Benchmarks

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