Soil pH

AUS-TDG-LVG-SPH General Moderate confidence

Benchmark Value

7.5 pH
Thresholds: Lower: —, Upper: 7.5
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.

Evidence & Context

A soil pH(CaCl₂) consistently above 7.0-7.5 may begin to indicate conditions that are less optimal for the typical suite of native flora and could lead to nutrient imbalances or other subtle ecological shifts.

Metric Definition:

Upper detrimental threshold for soil pH beyond which ecological health may decline.

Benchmark Definition:

This benchmark defines the upper detrimental soil pH threshold beyond which ecosystem function may be impaired due to nutrient imbalances and shifts in native plant communities.

Justification:

Above this pH, nutrient imbalances and shifts in native plant community composition may occur.

Sources (1)

Preview of Soil Quality Knowledge Base. (n.d.). Soil pH.
Soil Quality Knowledge Base. (n.d.). Soil pH. GreyLiterature

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

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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 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.
Contextual Support 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

Context

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

Lifecycle

  • Status Superseded
  • Version 1
  • Effective From 24 Mar 2026
  • Effective To 24 Mar 2026

Notes

This threshold applies to systems not inherently alkaline or sodic.