Soil Phosphorus

AUS-TMI-CON-SOP General Low confidence

Benchmark Value

2 mg/kg

Direction: Lower 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 11 benchmarks together — the OptimalRange form drives the primary score, while 10 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Critically Low <2 mg/kg indicates potential nutrient limitation even for highly adapted native flora.

Metric Definition:

Available phosphorus (Colwell P) concentration in soil, measured by the Colwell P test, representing the plant-available phosphorus fraction relevant for ecological health assessment.

Benchmark Definition:

This benchmark defines the lower critical threshold below which potential nutrient limitation occurs even for highly adapted native flora in phosphorus-sensitive tropical and subtropical maritime island conservation areas.

Justification:

This threshold is largely theoretical and represents a state of extreme phosphorus limitation.

Sources (1)

Preview of Common soil types | Environment, land and water | Queensland ...

Common soil types | Environment, land and water | Queensland ... Government

Phosphorus nutrition of phosphorus-sensitive Australian native ...

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Supporting Sources (6)

Additional references from the underlying research that informed this benchmark.

A simple phosphorus buffering index for Australian soils - ResearchGate

Contextual Support GreyLiterature

(PDF) A simple phosphorus buffering index for Australian soils - ResearchGate

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Preview of Critical phosphorus values from the Better Fertiliser Decisions for Pastures project: early insights from validation trials - BioOne Complete, accessed July 28, 2025,

Critical phosphorus values from the Better Fertiliser Decisions for Pastures project: early insights from validation trials - BioOne Complete, accessed July 28, 2025,

Direct Evidence Journal

Soil nutrient critical limits | MBFP | More Beef from Pastures - MLA

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LORD HOWE ISLAND BOARD On-Site Wastewater Management ...

Contextual Support Journal

LORD HOWE ISLAND BOARD On-Site Wastewater Management ...

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