Soil Potassium

AUS-AMR-AGR-SOK General Moderate confidence

Benchmark Value

No specific value — see range
Range: 120 to 120 mg/kg
Thresholds: Lower: 10, Upper: 250
Optimal Range: 120 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 15 benchmarks together — the OptimalRange form drives the primary score, while 14 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The benchmark represents the "Ideal" range for available potassium (Colwell K or equivalent) in productive agricultural soils, stratified by texture.

Metric Definition:

Available potassium (Colwell K or equivalent) in productive agricultural soils

Benchmark Definition:

This benchmark defines the ideal range of available potassium in productive agricultural soils within Australia's Arid Mountain Ranges & Uplands, representing a state of high ecological health and resilience for sustainable crop production.

Justification:

The value is derived from a synthesis of agronomic and ecological principles. The lower threshold indicates nutrient stress below which plant health and water use efficiency are compromised. The upper threshold reflects systemic imbalance risks such as magnesium deficiency and environmental leaching on certain soils.

Sources (1)

Preview of (PDF) Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia - ResearchGate, accessed July 18, 2025,
(PDF) Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia - ResearchGate, accessed July 18, 2025, Journal

The Western Australian Rangeland Monitoring System (WARMS) – operating a regional scale monitoring system - ResearchGate, accessed July 24, 2025

View Source

Context

  • Region Australia
  • Biome Arid Mountain Ranges & Uplands
  • Land Use Agricultural Crop Production
  • Assessment Pristine Reference
  • Evidence Type TargetCondition

Lifecycle

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

Notes

Lower Critical Threshold: 40 mg/kg. Upper Detrimental Threshold: 10 mg/kg (noting this value appears inconsistent with the optimal range and may represent a systemic imbalance threshold rather than a strict upper limit). Optimal range is 120-250 mg/kg, stratified by soil texture. [Migration] Original wider evidence range: 40 – 250 (retained OptimalRange: 120 – 120)