Soil Phosphorus

AUS-AMR-FOR-SOP General Low confidence

Benchmark Value

5 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 14 benchmarks together — the OptimalRange form drives the primary score, while 13 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

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

Metric Definition:

Available soil phosphorus measured as Colwell-P, indicating the minimum critical level below which ecosystem function is impaired.

Benchmark Definition:

This benchmark defines the critical lower threshold of available soil phosphorus below which forest health and productivity are significantly compromised in production forestry of arid mountain ranges and uplands in Australia.

Justification:

Based on agronomic proxies and ecological principles, supported by government soil classification frameworks and large-scale experiments indicating phosphorus limitation.

Sources (1)

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, Journal

(PDF) Soil and vegetation response to thinning White Cypress Pine ...

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

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.

Contextual Support Journal

(PDF) Too much of a good thing: phosphorus over-fertilisation in ...

View Source

Context

Region Australia
Biome Arid Mountain Ranges & Uplands
Land Use Production Forestry
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 10 Jun 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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