Soil Potassium

AUS-TDG-FOR-SOK General Moderate confidence

Benchmark Value

No specific value — see range
Range: 70 to 120 mg/kg
Optimal Range: 70 to 120
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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard Point Guard MaximumOnly Guard UpperThreshold Guard OptimalRange Guard LowerThreshold Guard Point Guard MinimumOnly Guard OptimalRange Guard

Evidence & Context

Optimal Range: The benchmark value of ~70-80 mg/kg is considered to fall within an ecologically optimal range. A broader optimal range, accommodating soil type variability, could be considered as approximately 70-120 mg/kg for common sandy to loamy soils in these woodlands, or more adaptably, maintaining potassium saturation at 1-5% of the Cation Exchange Capacity (CEC).

Metric Definition:

Optimal soil potassium range supporting healthy ecosystem function and sustainable production forestry.

Benchmark Definition:

Range of soil potassium concentrations considered optimal for ecosystem health and production forestry sustainability.

Justification:

Based on benchmark value and soil type variability, including CEC considerations.

Sources (2)

Preview of Agriculture Victoria. (2024). Understanding soil tests for pastures.
Agriculture Victoria. (2024). Understanding soil tests for pastures. Government

Agriculture Victoria. (2024). Understanding soil tests for pastures.

View Source
Preview of Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025
Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025 Government

Understanding soil tests for pastures

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Daws, M. I., Standish, R. J., Grigg, A. H., Morald, T. K., & Tibbett, M. (2021). Seeing the forest for the trees: fertiliser increases tree growth but decreases understorey diversity in the Northern Jarrah Forest, southwest Australia. Journal of the Royal Society of Western Australia, 104, 5-9.
Daws, M. I., Standish, R. J., Grigg, A. H., Morald, T. K., & Tibbett, M. (2021). Seeing the forest for the trees: fertiliser increases tree growth but decreases understorey diversity in the Northern Jarrah Forest, southwest Australia. Journal of the Royal Society of Western Australia, 104, 5-9.
Contextual Support Journal

Daws, M. I., Standish, R. J., Grigg, A. H., Morald, T. K., & Tibbett, M. (2021). Seeing the forest for the trees: fertiliser increases tree growth but decreases understorey diversity in the Northern Jarrah Forest, southwest Australia. Journal of the Royal Society of Western Australia, 104, 5-9.

View Source
Preview of Restoring Australia's temperate grasslands and grassy woodlands | Request PDF - ResearchGate, accessed August 6, 2025,
Restoring Australia's temperate grasslands and grassy woodlands | Request PDF - ResearchGate, accessed August 6, 2025,
Contextual Support Journal

Prober, S. M., Thiele, K. R., & Loneragan, W. A. (2005). Relationships among soil fertility, native plant diversity and exotic plant abundance inform restoration of forb-rich eucalypt woodlands. Austral Ecology, 30(6), 607-618.

View Source
Preview of Sapsford, S. J., Paap, T., Hardy, G. E. St. J., & Burgess, T. I. (2021). Anthropogenic Disturbance Impacts Mycorrhizal Communities and Abiotic Soil Properties: Implications for an Endemic Forest Disease. Frontiers in Forests and Global Change, 3, 593243.
Sapsford, S. J., Paap, T., Hardy, G. E. St. J., & Burgess, T. I. (2021). Anthropogenic Disturbance Impacts Mycorrhizal Communities and Abiotic Soil Properties: Implications for an Endemic Forest Disease. Frontiers in Forests and Global Change, 3, 593243.
Contextual Support Journal

Sapsford, S. J., Paap, T., Hardy, G. E. St. J., & Burgess, T. I. (2021). Anthropogenic Disturbance Impacts Mycorrhizal Communities and Abiotic Soil Properties: Implications for an Endemic Forest Disease. Frontiers in Forests and Global Change, 3, 593243.

View Source

Context

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

Lifecycle

  • Status Active
  • Version 2
  • Effective From 24 Mar 2026

Notes

Supports healthy tree growth and ecosystem function without adverse effects of over-enrichment.

Related Benchmarks

Other benchmarks in the AUS-TDG-FOR-SOK family.

120 mg/kg Moderate
Production Forestry · Pristine Reference
MaximumOnly Active v1
74.1 mg/kg Moderate
Production Forestry · Pristine Reference
Point Active v1
50 mg/kg Moderate
Production Forestry · Pristine Reference
LowerThreshold Active v1
80 mg/kg Moderate
Production Forestry · Pristine Reference
LowerThreshold Active v1
120 mg/kg Moderate
Production Forestry · Pristine Reference
UpperThreshold Active v1
74.1 mg/kg Moderate
Production Forestry · Pristine Reference
Point Active v1
— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Superseded v1