Soil pH

AUS-TDG-LVG-SPH General High confidence

Benchmark Value

No specific value — see range
Range: 5 to 5.5 pH
Optimal Range: 5 to 5.5
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.

Evidence & Context

The key findings for soil pH(CaCl₂) were: Mean pH(CaCl₂) beneath tree canopies: 5.50 (with an observed range of 4.5 – 6.4). Mean pH(CaCl₂) in open inter-tree areas: 5.01 (with an observed range of 4.4 – 5.6).

Metric Definition:

Topsoil pH measured in a 0.01 M calcium chloride (CaCl₂) solution.

Benchmark Definition:

This benchmark represents the typical soil pH range measured in a calcium chloride solution in temperate dry woodlands and native grasslands under livestock grazing, reflecting healthy ecosystem function with spatial variation under tree canopies and open areas.

Justification:

The benchmark is based on mean pH values observed in little-grazed remnants representing high environmental health and ecological function.

Sources (1)

Preview of Prober, S. M., Lunt, I. D., & Thiele, K. R. (2002). Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany, 50(6), 687–697.
Prober, S. M., Lunt, I. D., & Thiele, K. R. (2002). Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany, 50(6), 687–697. Journal

Prober, S. M., Lunt, I. D., & Thiele, K. R. (2002). Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany, 50(6), 687–697.

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Agriculture Victoria. (2024). Soil acidity.
Agriculture Victoria. (2024). Soil acidity.
Contextual Support

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

View Source
Preview of Government of South Australia, Department for Environment and Water. (n.d.). Soil Health and Condition.
Government of South Australia, Department for Environment and Water. (n.d.). Soil Health and Condition.
Contextual Support Government

Soil acidity - Department for Environment and Water, accessed July 30, 2025,

View Source
Preview of Soil Quality Knowledge Base. (n.d.). Soil pH.
Soil Quality Knowledge Base. (n.d.). Soil pH.
Contextual Support GreyLiterature

Working with bio-amendments: Insights from cropping farmers - Soils For Life, accessed July 7, 2025,

View Source

Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Vegetation Woodland
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 24 Mar 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. The benchmark reflects spatial heterogeneity with distinct values under tree canopies and open areas, representing a healthy functioning ecosystem. [Migration] Original wider evidence range: 4.4 – 6.4 (retained OptimalRange: 5 – 5.5)