Soil Potassium

AUS-TMI-CON-SOK General Moderate confidence

Benchmark Value

120 mg/kg
Direction: Higher is desirable ↑
Form: MinimumOnly

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context.

Evidence & Context

A lower critical threshold, below which ecosystem function may be compromised, is estimated at <120 mg/kg, particularly on low-CEC sandy or calcareous soils.

Metric Definition:

Lower critical threshold for soil potassium below which ecosystem function may be compromised

Benchmark Definition:

This benchmark represents the minimum soil potassium level below which ecosystem function may be compromised in tropical and subtropical maritime island conservation areas, especially on low-CEC sandy or calcareous soils.

Justification:

Based on agronomic guidelines and ecological context indicating potential K limitation and ecological stress below this level.

Sources (1)

Preview of Grant, M. (2023). Seabirds as vectors for nutrients and pollutants to islands. PhD Thesis, University of Tasmania. Data from Table 3-3, Chapter 3.
Grant, M. (2023). Seabirds as vectors for nutrients and pollutants to islands. PhD Thesis, University of Tasmania. Data from Table 3-3, Chapter 3. GreyLiterature

Grant, M. (2023). Seabirds as vectors for nutrients and pollutants to islands. PhD Thesis, University of Tasmania. Data from Table 3-3, Chapter 3.

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of Geology | Norfolk Island National Park | Parks Australia, accessed August 2, 2025,
Geology | Norfolk Island National Park | Parks Australia, accessed August 2, 2025,
Contextual Support Journal

Geology | Norfolk Island National Park | Parks Australia, accessed August 2, 2025

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Maritime Islands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Not Stated
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 9 Jun 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. Particularly relevant for low-CEC sandy or calcareous soils where potassium availability constrains ecosystem function. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.