Soil Phosphorus

AUS-TGP-LVG-SOP General Moderate confidence

Benchmark Value

13 mg/kg

Direction: Higher is desirable ↑

Form: MaximumOnly

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 3 benchmarks together — the OptimalRange form drives the primary score, while 2 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard MaximumOnly Guard

Evidence & Context

The Upper Detrimental Threshold is defined as > 13 mg/kg Olsen P. Above this level, the ecosystem is no longer representative of a "best-on-offer" native grassy woodland.

Metric Definition:

Soil phosphorus concentration above which native grassy woodland ecosystems degrade and lose biodiversity.

Benchmark Definition:

This benchmark marks the maximum soil phosphorus level before native grassy woodlands begin to degrade and lose biodiversity.

Justification:

Supported by multiple studies showing loss of native species richness and ecosystem integrity above this phosphorus level.

Sources (2)

Preview of Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025, Journal

How should we manage our soils to increase soil carbon?, accessed May 10, 2026

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, Government

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

Supporting Sources (18)

Additional references from the underlying research that informed this benchmark.

Preview of A comparison of some surface soil phosphorus tests that could be used to assess P export potential - CSIRO Publishing, accessed August 5, 2025,

A comparison of some surface soil phosphorus tests that could be used to assess P export potential - CSIRO Publishing, accessed August 5, 2025,

Methodology Source Journal

A comparison of some surface soil phosphorus tests that could be used to assess P export potential - CSIRO Publishing

Preview of A review of the economics of regenerative agriculture in Western Australia - DPIRD's Digital library, accessed August 4, 2025

A review of the economics of regenerative agriculture in Western Australia - DPIRD's Digital library, accessed August 4, 2025

Contextual Support Journal

A review of the economics of regenerative agriculture in Western Australia - DPIRD's Digital library

Preview of Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,

Contextual Support Journal

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

Preview of Australian Journal of Botany - CSIRO PUBLISHING, accessed August 11, 2025

Australian Journal of Botany - CSIRO PUBLISHING, accessed August 11, 2025

Contextual Support Journal

Individual plant species responses to phosphorus and livestock grazing - CSIRO PUBLISHING | Australian Journal of Botany

Preview of Building Healthy Pasture Soils - ATTRA – Sustainable Agriculture - NCAT, accessed August 5, 2025,

Building Healthy Pasture Soils - ATTRA – Sustainable Agriculture - NCAT, accessed August 5, 2025,

Contextual Support GreyLiterature

Managing Grazing to Restore Soil Health, Ecosystem Function, and Ecosystem Services - Frontiers

Preview of Correlations between ∆EP measured by the Olsen P and Colwell P methods... | Download Scientific Diagram - ResearchGate, accessed August 5, 2025,

Correlations between ∆EP measured by the Olsen P and Colwell P methods... | Download Scientific Diagram - ResearchGate, accessed August 5, 2025,

Methodology Source Journal

Correlations between ∆EP measured by the Olsen P and Colwell P methods... | Download Scientific Diagram - ResearchGate

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,

Contextual Support Journal

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

Preview of Critical phosphorus values from the Better Fertiliser Decisions for Pastures project: early insights from validation trials - CSIRO Publishing, accessed August 5, 2025,

Critical phosphorus values from the Better Fertiliser Decisions for Pastures project: early insights from validation trials - CSIRO Publishing, accessed August 5, 2025,

Direct Evidence Journal

Critical phosphorus values from the Better Fertiliser Decisions for Pastures project: early insights from validation trials - CSIRO Publishing

Preview of Improving phosphorus management in intensive Australian grazing ..., accessed August 5, 2025,

Improving phosphorus management in intensive Australian grazing ..., accessed August 5, 2025,

Contextual Support GreyLiterature

Improving phosphorus management in intensive Australian grazing ...

Preview of Overgrazing & Reducing Grazing Pressure | Bush Heritage Australia, accessed July 28, 2025,

Overgrazing & Reducing Grazing Pressure | Bush Heritage Australia, accessed July 28, 2025,

Contextual Support Journal

Cycling of phosphorus in grazing systems - NSW Department of Primary Industries

Preview of Phosphorus constraints to potential land area cropped under organic and regenerative systems in Australia | Request PDF - ResearchGate, accessed July 22, 2025,

Phosphorus constraints to potential land area cropped under organic and regenerative systems in Australia | Request PDF - ResearchGate, accessed July 22, 2025,

Contextual Support

Understanding soil tests for pastures | Soil | Farm management ...

Preview of Phosphorus fertiliser management for pastures based on native grasses in south-eastern Australia - ResearchGate, accessed July 18, 2025,

Phosphorus fertiliser management for pastures based on native grasses in south-eastern Australia - ResearchGate, accessed July 18, 2025,

Contextual Support Journal

Soil phosphorus and tree cover modify the effects of livestock grazing on plant species richness in Australian grassy woodland - ResearchGate

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

Contextual Support Journal

Phosphorus nutrition of phosphorus-sensitive Australian native plants: threats to plant communities in a global biodiversity hotspot - PMC

Preview of Soil phosphorus and tree cover modify the effects of livestock grazing on plant species richness in Australian grassy woodland - ResearchGate, accessed July 10, 2025,

Soil phosphorus and tree cover modify the effects of livestock grazing on plant species richness in Australian grassy woodland - ResearchGate, accessed July 10, 2025,

Contextual Support

Regenerative agriculture in Australia: the changing face of farming - Frontiers

Preview of The phosphorus and nitrogen requirements of temperate pasture species and their influence on grassland botanical composition - CSIRO Publishing, accessed August 5, 2025,

The phosphorus and nitrogen requirements of temperate pasture species and their influence on grassland botanical composition - CSIRO Publishing, accessed August 5, 2025,

Contextual Support Journal

3- Build and maintain soil nutrients to improve soil fertility and health in all pasture zones

Preview of Tool 6.7 Soil health benchmarks and guidelines for managing problem soils, accessed August 9, 2025

Tool 6.7 Soil health benchmarks and guidelines for managing problem soils, accessed August 9, 2025

Contextual Support GreyLiterature

Managing soils to keep them healthy and productive - MLA

Preview of Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025

Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025

Contextual Support Government

Agriculture Victoria. (2025). Understanding soil tests for pastures. Farm Management.

Preview of What soil phosphorus pools and processes do ... - CSIRO Publishing, accessed August 5, 2025,

What soil phosphorus pools and processes do ... - CSIRO Publishing, accessed August 5, 2025,

Methodology Source Journal

Soil phosphorus tests I: What soil phosphorus pools and processes do they measure?

Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Livestock Grazing & Pasture
Assessment Conservation Target
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 10 Jun 2026

Notes

This threshold corresponds approximately to a Colwell P value of 20 mg/kg on moderate PBI soils.

Related Benchmarks

Other benchmarks in the AUS-TGP-LVG-SOP family.