Soil Potassium

AUS-TDG-FOR-SOK General Moderate confidence

Benchmark Value

74.1 mg/kg
Range: 70 to 79.5 mg/kg
Optimal Range: 70 to 79.5
Direction: Higher is desirable ↑
Form: Point

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

The recommended soil potassium reference value for representing the "best available condition of nature" under sustainable Production Forestry in Australian Temperate Dry Woodlands & Native Grasslands is approximately 74.1±5.4 mg/kg (likely Colwell-K or equivalent extractable K).

Metric Definition:

Soil potassium concentration representing the best available ecological condition in sustainably managed production forests in the Temperate Dry Woodlands & Native Grasslands biome.

Benchmark Definition:

Soil potassium concentration indicative of the best available ecological condition in production forestry within the specified biome.

Justification:

Based on a peer-reviewed study linking soil potassium levels to ecological health indicators in a relevant Australian temperate eucalypt woodland, representing a high environmental health condition though not explicitly defined as production forestry.

Sources (3)

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 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. 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 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. 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

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

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 Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025
Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025
Contextual Support Government

Understanding soil tests for pastures

View Source

Context

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

Lifecycle

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

Notes

Value from "intact forest" sites in Corymbia calophylla woodland (SW WA) showing higher ecological health compared to disturbed sites with higher K. Lower Critical Threshold likely <50-80 mg/kg; Optimal Range approx. 70-80 mg/kg; broader optimal range 70-120 mg/kg for sandy/loamy soils or 1-5% K saturation of CEC. Upper Detrimental Threshold: K levels >10% of CEC can induce Mg deficiency; values >100-120 mg/kg may indicate disturbance or nutrient imbalance. [Migration] Original wider evidence range: 68.7 – 80 (retained OptimalRange: 70 – 79.5)

Related Benchmarks

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

— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Active v2
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
— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Superseded v1