Soil Phosphorus

AUS-AMR-CON-SOP General High confidence

Benchmark Value

No specific value — see range
Range: 5 to 8 mg/kg
Thresholds: Lower: 3, Upper: 20
Optimal Range: 5 to 8
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 reference value represents the median available P (Colwell P) for the 0-10cm soil layer, derived from the TERN Soil and Landscape Grid across all protected conservation areas (CAPAD) within the Arid Mountain Ranges & Uplands biome (defined by IBRA regions MAC, FLB, BHC, CER, PIL).

Metric Definition:

Available Phosphorus measured using the bicarbonate-extractable phosphorus method (Colwell P test) in the 0-10 cm soil layer.

Benchmark Definition:

Median available phosphorus concentration in surface soil representing the best available natural condition in conservation areas of the Arid Mountain Ranges & Uplands biome.

Justification:

The median is selected as the most appropriate measure of central tendency for this application, robust to outliers such as natural phosphate rock outcrops, reflecting the typical healthy low-P condition of the biome.

Sources (4)

Preview of Indicative Soil Phosphorus Report | LongPaddock | Queensland Government
Indicative Soil Phosphorus Report | LongPaddock | Queensland Government Government

Indicative Soil Phosphorus Report | LongPaddock | Queensland Government, accessed August 1, 2025

View Source
Preview of Phosphorus Nutrition of Proteaceae in Severely Phosphorus-Impoverished Soils: Are There Lessons To Be Learned for Future Crops? - PubMed Central, accessed August 4, 2025
Phosphorus Nutrition of Proteaceae in Severely Phosphorus-Impoverished Soils: Are There Lessons To Be Learned for Future Crops? - PubMed Central, accessed August 4, 2025 Journal

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC

View Source
Preview of Soil and Landscape Grid National Soil Attribute Maps - Available Phosphorus (3" resolution) - Release 1
Soil and Landscape Grid National Soil Attribute Maps - Available Phosphorus (3" resolution) - Release 1
View Source
Preview of Soil nutrient critical limits | MBFP | More Beef from Pastures - MLA, accessed May 13, 2025,
Soil nutrient critical limits | MBFP | More Beef from Pastures - MLA, accessed May 13, 2025, GreyLiterature

Understanding soil tests for pastures | Soil | Farm management ..., accessed July 17, 2025,

View Source

Supporting Sources (18)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate, accessed July 13, 2025
(PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate, accessed July 13, 2025
Contextual Support

(PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate

View Source
Preview of (PDF) Soil phosphorus tests II: A comparison of soil test–crop response relationships for different soil tests and wheat - ResearchGate, accessed July 7, 2025,
(PDF) Soil phosphorus tests II: A comparison of soil test–crop response relationships for different soil tests and wheat - ResearchGate, accessed July 7, 2025,
Methodology Source Journal

(PDF) Soil phosphorus tests II: A comparison of soil test–crop response relationships for different soil tests and wheat - ResearchGate, accessed August 1, 2025

View Source
Preview of Australia - Soils, Climate, Erosion | Britannica
Australia - Soils, Climate, Erosion | Britannica
Contextual Support GreyLiterature

SOIL TESTING, accessed August 1, 2025

View Source
Preview of Australia's bioregions (IBRA) - DCCEEW, accessed July 15, 2025
Australia's bioregions (IBRA) - DCCEEW, accessed July 15, 2025
Contextual Support

Interim Biogeographic Regionalisation for Australia (IBRA), Version 7 (Regions), accessed July 12, 2025,

View Source
Preview of Australian dryland soils are acidic and nutrient-depleted, and have ..., accessed August 1, 2025
Australian dryland soils are acidic and nutrient-depleted, and have ..., accessed August 1, 2025
Contextual Support

Australian dryland soils are acidic and nutrient-depleted, and have ..., accessed August 1, 2025

View Source
Preview of Global patterns and drivers of soil total phosphorus concentration - ESSD Copernicus, accessed on May 31, 2025
Global patterns and drivers of soil total phosphorus concentration - ESSD Copernicus, accessed on May 31, 2025
Contextual Support Journal

Global patterns and drivers of soil total phosphorus concentration - ESSD Copernicus, accessed August 1, 2025

View Source
Preview of Interim Biogeographic Regionalisation for Australia - Wikipedia, accessed July 13, 2025,
Interim Biogeographic Regionalisation for Australia - Wikipedia, accessed July 13, 2025,
Contextual Support GreyLiterature

Category:IBRA regions - Wikipedia, accessed August 1, 2025

View Source
Preview of Interim Biogeographic Regionalisation for Australia (IBRA7) Codes - DCCEEW, accessed August 1, 2025
Interim Biogeographic Regionalisation for Australia (IBRA7) Codes - DCCEEW, accessed August 1, 2025
Contextual Support Government

Cobar Peneplain bioregion - DCCEEW, accessed July 12, 2025,

View Source
Preview of Phosphate minerals from Reaphook Hill, Flinders Ranges, South Australia | Mineralogical Magazine | Cambridge Core, accessed August 1, 2025
Phosphate minerals from Reaphook Hill, Flinders Ranges, South Australia | Mineralogical Magazine | Cambridge Core, accessed August 1, 2025
Contextual Support

Phosphate minerals from Reaphook Hill, Flinders Ranges, South Australia - Cambridge University Press, accessed August 1, 2025

View Source
Preview of Phosphorus - Qld | Fact Sheets | soilquality.org.au, accessed August 28, 2025
Phosphorus - Qld | Fact Sheets | soilquality.org.au, accessed August 28, 2025
Contextual Support Government

Phosphorus - WA | Fact Sheets | soilquality.org.au, accessed August 1, 2025

View Source
Preview of Phosphorus nutrition of phosphorus-sensitive Australian native plants: threats to plant communities in a global biodiversity hotspot - PMC
Phosphorus nutrition of phosphorus-sensitive Australian native plants: threats to plant communities in a global biodiversity hotspot - PMC
Contextual Support Journal

(PDF) Sensitivity of seedling growth to phosphorus supply in six tree ..., accessed May 15, 2025,

View Source
Preview of Phosphorus requirements of Australian native plants - ResearchGate, accessed August 4, 2025
Phosphorus requirements of Australian native plants - ResearchGate, accessed August 4, 2025
Contextual Support Journal

The Big Phosphorus Issue - Australian Native Plants — The Gardeners Lodge, accessed August 1, 2025

View Source
Preview of Soil and Landscape Grid National Soil Attribute Maps - Available Phosphorus (3" resolution) - Release 1 - CSIRO Data Access Portal, accessed on May 31, 2025
Soil and Landscape Grid National Soil Attribute Maps - Available Phosphorus (3" resolution) - Release 1 - CSIRO Data Access Portal, accessed on May 31, 2025
Direct Evidence Government

Soil and Landscape Grid National Soil Attribute Maps - Available Phosphorus (3" resolution) - Release 1 - CSIRO Data Access Portal, accessed August 1, 2025

View Source
Preview of Soil and Landscape Grid National Soil Attribute Maps - Available Phosphorus (3" resolution) - TERN Data Discovery Portal, accessed August 1, 2025
Soil and Landscape Grid National Soil Attribute Maps - Available Phosphorus (3" resolution) - TERN Data Discovery Portal, accessed August 1, 2025
Contextual Support Government

Soil and Landscape Grid National Soil Attribute Maps - Total Phosphorus (3" resolution) - Release 2 - TERN Data Discovery Portal, accessed August 1, 2025

View Source
Preview of Soil and Landscape Grid of Australia - CSIRO, accessed July 30, 2025,
Soil and Landscape Grid of Australia - CSIRO, accessed July 30, 2025,
Contextual Support

Soil and Landscape Grid of Australia - CSIRO, accessed August 1, 2025

View Source
Preview of The incidence of low phosphorus soils in Australia | Request PDF - ResearchGate, accessed July 21, 2025,
The incidence of low phosphorus soils in Australia | Request PDF - ResearchGate, accessed July 21, 2025,
Contextual Support Journal

Survival of native plants of Hawkesbury Sandstone communities with additional nutrients: effect of plant age and habitat - ResearchGate, accessed August 1, 2025

View Source
Preview of THE PHOSPHATE CONTENT OF AUSTRALIAN SOILS - CSIRO Publishing, accessed August 1, 2025
THE PHOSPHATE CONTENT OF AUSTRALIAN SOILS - CSIRO Publishing, accessed August 1, 2025
Contextual Support Journal

THE PHOSPHATE CONTENT OF AUSTRALIAN SOILS - CSIRO Publishing, accessed August 1, 2025

View Source
Preview of Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics, accessed August 1, 2025
Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics, accessed August 1, 2025
Contextual Support GreyLiterature

Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics, accessed August 1, 2025

View Source

Context

  • Region Australia
  • Biome Arid Mountain Ranges & Uplands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type ReferenceCondition

Lifecycle

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

Notes

Lower Critical Threshold: 3 mg/kg. Upper Detrimental Threshold: 20 mg/kg. Optimal ecological range is 5-15 mg/kg supporting biodiversity and ecosystem resilience. [Migration] Original wider evidence range: 5 – 15 (retained OptimalRange: 5 – 8)