Soil Potassium

AUS-AKW-CON-SOK General Moderate confidence

Benchmark Value

30 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. The scoring engine uses 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard Point Guard MinimumOnly Guard MaximumOnly Guard

Evidence & Context

A lower critical threshold of approximately 30 mg/kg (Colwell K) is proposed. Below this level, it is highly probable that the drought-tolerance mechanisms of the native flora would be impaired, leading to reduced resilience and a decline in ecosystem health.

Metric Definition:

Lower critical threshold of available soil potassium below which key ecosystem functions, especially drought resilience, are impaired.

Benchmark Definition:

Lower critical threshold for soil potassium indicating the minimum level for ecosystem function in Arid Karstic Woodlands & Shrublands under conservation management.

Justification:

Based on agronomic critical values for low-demand crops (lupins) and ecological inference for native flora drought tolerance.

Sources (3)

Preview of "Soil potassium-crop response calibration relationships and criteria for field crops grown in Australia"
"Soil potassium-crop response calibration relationships and criteria for field crops grown in Australia" Journal

"Soil Groups of Western Australia"

View Source
Preview of Estimating woody vegetation cover in arid and semi-arid rangelands - Murdoch Research Portal, accessed July 12, 2025,
Estimating woody vegetation cover in arid and semi-arid rangelands - Murdoch Research Portal, accessed July 12, 2025, Journal

Agronomic and ecological studies on potassium excess effects

View Source
Preview of Nullarbor Plains Xeric Shrublands | One Earth, accessed July 26, 2025,
Nullarbor Plains Xeric Shrublands | One Earth, accessed July 26, 2025,

Ecological literature on nutrient adaptation in arid ecosystems

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate, accessed July 13, 2025
(PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate, accessed July 13, 2025
Contextual Support

Putting the P in Ptilotus: a phosphorus-accumulating herb native to Australia - PMC

View Source

Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 10 Jun 2026

Notes

Below this level, functions related to plant water regulation and drought stress tolerance are likely impaired.

Related Benchmarks

Other benchmarks in the AUS-AKW-CON-SOK family.

80 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
Point Active v1
— mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
OptimalRange Active v1
300 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Active v1