Soil Phosphorus

AUS-AMR-FOR-SOP General Moderate confidence

Benchmark Value

5 mg/kg
Thresholds: Lower: 5, Upper: —
Direction: Higher is desirable ↑
Form: LowerThreshold

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 16 benchmarks together — the OptimalRange form drives the primary score, while 15 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard LowerThreshold Guard UpperThreshold Guard LowerThreshold Guard MinimumOnly Guard OptimalRange Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard Point Guard OptimalRange Guard MinimumOnly Guard Point Guard LowerThreshold Guard OptimalRange Guard

Evidence & Context

Lower Critical Threshold: A Colwell-P level of < 5 mg/kg is considered critically low.

Metric Definition:

Lower critical threshold for available soil phosphorus (Colwell-P) below which forest health and productivity are significantly compromised.

Benchmark Definition:

Lower critical threshold for available soil phosphorus (Colwell-P) below which forest health and productivity are significantly compromised.

Justification:

Soil P levels below this point indicate a state of significant nutrient stress where the long-term sustainability of production forestry is questionable without careful, targeted nutrient inputs.

Sources (1)

Preview of Synthesis of peer-reviewed literature and government technical reports on soil phosphorus dynamics in managed Australian native ecosystems.
Synthesis of peer-reviewed literature and government technical reports on soil phosphorus dynamics in managed Australian native ecosystems.
View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Too much of a good thing: phosphorus over-fertilisation in ..., accessed July 30, 2025,
(PDF) Too much of a good thing: phosphorus over-fertilisation in ..., accessed July 30, 2025,
Direct Evidence Journal

Review of fertiliser use in Australian forestry - Forest & Wood ..., accessed July 30, 2025,

View Source

Context

  • Region Australia
  • Biome Arid Mountain Ranges & Uplands
  • Land Use Production Forestry
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

Corresponds to the 'Extremely Low' and 'Very Low' classifications used in government frameworks.

Related Benchmarks

Other benchmarks in the AUS-AMR-FOR-SOP family.

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