Soil Phosphorus

AUS-TSW-FOR-SOP General Moderate confidence

Benchmark Value

15 mg/kg

Range: 5 to 15 mg/kg

Thresholds: Lower: 5, Upper: 20

Optimal Range: 5 to 15

Direction: Higher is desirable ↑

Form: Point

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

The benchmark of 15 mg/kg (available P, e.g., Colwell-P) represents the optimal level for balancing ecological health and productivity in this P-sensitive biome.

Metric Definition:

Available soil phosphorus (e.g., Colwell-P) concentration representing the best available condition for balancing ecological health and productivity in production forestry.

Benchmark Definition:

This benchmark represents the optimal available soil phosphorus concentration for balancing ecological health and productivity in production forestry within the temperate semi-arid shrublands and open woodlands biome.

Justification:

Derived from studies on analogous semi-arid woodland species and supported by agronomic literature defining adequate soil P levels for commercial eucalypt growth.

Sources (2)

Preview of ABARES report reaffirms sustainability, sovereign capability and climate credentials of Australian native forestry, accessed August 10, 2025,

ABARES report reaffirms sustainability, sovereign capability and climate credentials of Australian native forestry, accessed August 10, 2025, GreyLiterature

Review of fertiliser use in Australian forestry - Forest & Wood Products Australia

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Sensitivity of seedling growth to phosphorus supply in six tree species of the Australian Great Western Woodlands Journal

Sensitivity of seedling growth to phosphorus supply in six tree species of the Australian Great Western Woodlands

View Source

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Preview of Australian Bureau of Agricultural and Resource Economics report shows Australia harvests 0.05% of native forests annually for timber, wood products, and those acres are then regenerated; national forest area grew by 2.8 million hectares from 2008 to 2021 - Industry Intelligence Inc.

Australian Bureau of Agricultural and Resource Economics report shows Australia harvests 0.05% of native forests annually for timber, wood products, and those acres are then regenerated; national forest area grew by 2.8 million hectares from 2008 to 2021 - Industry Intelligence Inc.

Contextual Support

View Source

National Soil Monitoring Program - CSIRO, accessed August 4, 2025,

Contextual Support GreyLiterature

National Soil Monitoring Program - CSIRO

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Production Forestry
Assessment Pristine Reference
Evidence Type TargetCondition

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

Lower Critical Threshold: 5 mg/kg. Upper Detrimental Threshold: 20 mg/kg. Lower critical threshold at < 5 mg/kg indicates severe P deficiency compromising tree growth; upper detrimental threshold at > 20 mg/kg indicates toxicity and negative biodiversity impacts.