Soil Phosphorus

AUS-AKW-CON-SOP General Moderate confidence

Benchmark Value

No specific value — see range
Range: 2 to 15 mg/kg
Optimal Range: 2 to 15
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 8 benchmarks together — the OptimalRange form drives the primary score, while 7 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

the proposed optimal range for available phosphorus (Colwell-P) in this biome is 2 - 15 mg/kg

Metric Definition:

Available phosphorus as measured by Colwell-P test representing the range within which native ecosystem integrity is maintained.

Benchmark Definition:

This benchmark defines the optimal range of available phosphorus for maintaining native ecosystem integrity in the Arid Karstic Woodlands & Shrublands biome.

Justification:

This range balances nutrient availability against the risk of competitive exclusion by P-responsive species.

Sources (1)

Preview of An inventory and condition survey of the Western Australian part of the Nullarbor region, accessed July 25, 2025
An inventory and condition survey of the Western Australian part of the Nullarbor region, accessed July 25, 2025 Journal

(PDF) Phosphorus status and saturation in soils that drain into the ...

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Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type HealthyOperationalRange

Lifecycle

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

Notes

Lower end (2-6 mg/kg) reflects natural P-limited state; upper end (6-15 mg/kg) requires vigilant management due to vulnerability to weed invasion.

Related Benchmarks

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

2 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Active v2
20 mg/kg Moderate
Conservation / Protected Natural Areas · Conservation Target
MinimumOnly Active v1
2 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Superseded v1