Soil pH — Benchmark Detail

Benchmark Value

8.5 pH

Thresholds: Lower: —, Upper: 8.5

Direction: Higher is desirable ↑

Form: UpperThreshold

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

Detrimental effects from high alkalinity are rare in this biome but can occur above pH 8.5, typically associated with sodicity.

Metric Definition:

Topsoil pH measured in 0.01 M CaCl2

Benchmark Definition:

Upper detrimental threshold beyond which soil alkalinity causes harm in Temperate Grassy Woodlands & Plains under Livestock Grazing & Pasture.

Justification:

pH above 8.5 is linked to sodicity and poor soil structure causing degradation.

Sources (1)

Preview of Procedure for Soil Respiration (CO2 Evolution from Rewetting a Dried Soil) - Soil Fertility, accessed July 9, 2025

Procedure for Soil Respiration (CO2 Evolution from Rewetting a Dried Soil) - Soil Fertility, accessed July 9, 2025 GreyLiterature

Soil pH and Organic Matter - MSU Extension | Montana State University, accessed July 28, 2025,

View Source

Supporting Sources (11)

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,

Contextual Support Journal

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

View Source

Agriculture Victoria. (2024). Soil acidity.

Contextual Support

Soil acidity | Soil | Farm management - Agriculture Victoria, accessed August 28, 2025

View Source

Preview of Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,

Contextual Support Journal

Root Structure and Functioning for Efficient Acquisition of Phosphorus: Matching Morphological and Physiological Traits

View Source

Do grazing intensity and herbivore type affect soil health? Insights from a semi-arid productivity gradient, accessed July 24, 2025

Contextual Support Journal

Soil acidification | .Meat & Livestock Australia, accessed August 5, 2025,

View Source

Managing soils - Department of Primary Industries and Regional Development, accessed August 12, 2025

Contextual Support Government

Repairing gully erosion in Western Australia | Department of Primary ...

View Source

Preview of Natural Temperate Grassland of the South Eastern Highlands: a nationally protected ecological community - DCCEEW, accessed August 12, 2025,

Natural Temperate Grassland of the South Eastern Highlands: a nationally protected ecological community - DCCEEW, accessed August 12, 2025,

Contextual Support Journal

Australia's Native Vegetation Framework - DAFF

View Source

NSW Department of Primary Industries. (2021). Soil Acidity and Liming (AC.19).

Contextual Support Government

Soil acidity and liming. 4th edition 2021 - NSW Department of Primary Industries, accessed July 28, 2025,

View Source

Pastures and acid soils - NSW Government

Contextual Support Journal

What do you see and when? What could this indicate? What test can I do to confirm? - MLA

View Source

Soil pH - SA | Fact Sheets | soilquality.org.au

Contextual Support Government

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

What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed August 5, 2025,

Contextual Support Government

Scanlan, C. A., et al. (2013). Soil Quality: 10 Plant Nutrition. CCMA Soil Health Knowledge Base.

View Source

Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Livestock Grazing & Pasture
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

High pH can induce micronutrient deficiencies and toxicities.

Related Benchmarks

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