Soil pH

AUS-TDG-FOR-SPH General Moderate confidence

Benchmark Value

6.5 pH
Thresholds: Lower: —, Upper: 6.5
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 16 benchmarks together — the OptimalRange form drives the primary score, while 15 guard(s) constrain the result.

Evidence & Context

For these naturally moderately acidic Temperate Dry Woodlands, a sustained soil pH (CaCl₂) significantly and consistently above approximately 6.5 - 7.0 could be considered detrimental to the natural ecosystem balance and native species composition.

Metric Definition:

Soil pH measured in a 1:5 soil:0.01M CaCl₂ solution indicating the acidity level above which ecosystem integrity and native species composition are compromised.

Benchmark Definition:

This benchmark represents the upper detrimental soil pH threshold measured in CaCl₂ solution beyond which nutrient imbalances and shifts in native plant communities occur in Temperate Dry Woodlands & Native Grasslands under production forestry.

Justification:

Sustained pH above 6.5-7.0 may lead to ecological imbalances, nutrient deficiencies, and altered native species composition, indicating departure from best available natural condition.

Sources (1)

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

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

View Source

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Preview of Prober, S.M., Thiele, K.R., & Lunt, I.D. (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., Thiele, K.R., & Lunt, I.D. (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., Thiele, K.R., & Lunt, I.D. (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
Preview of Temperate Grasslands - Greening Australia, accessed August 4, 2025
Temperate Grasslands - Greening Australia, accessed August 4, 2025
Contextual Support Journal

Managing natural areas | City of Gold Coast, accessed May 19, 2025

View Source

Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Production Forestry
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 25 Mar 2026

Notes

Reflects an ecological harm boundary for soil alkalinity in the biome.