Soil Phosphorus

AUS-TSW-CON-SOP General Moderate confidence

Benchmark Value

75 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 7 benchmarks together — the OptimalRange form drives the primary score, while 6 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

An upper detrimental threshold is identified at ~75 mg/kg (Colwell-P), representing a state of severe ecological degradation.

Metric Definition:

Available soil phosphorus measured by the Colwell-P method.

Benchmark Definition:

This benchmark marks an upper detrimental threshold of available soil phosphorus indicating severe ecological degradation in temperate semi-arid woodlands.

Justification:

This value represents a state of severe ecosystem degradation with catastrophic loss of native flora.

Sources (1)

Preview of Individual plant species responses to phosphorus and livestock grazing

Individual plant species responses to phosphorus and livestock grazing Journal

Individual plant species responses to phosphorus and livestock grazing

Supporting Sources (16)

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

Preview of A new detailed map of total phosphorus stocks in Australian soil - ResearchGate, accessed August 11, 2025

A new detailed map of total phosphorus stocks in Australian soil - ResearchGate, accessed August 11, 2025

Contextual Support Journal

A new detailed map of total phosphorus stocks in Australian soil

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

Root Structure and Functioning for Efficient Acquisition of Phosphorus: Matching Morphological and Physiological Traits

Preview of Australian dryland soils are acidic and nutrient‐depleted, and have

Australian dryland soils are acidic and nutrient‐depleted, and have

Contextual Support Journal

Australian dryland soils are acidic and nutrient‐depleted, and have

Preview of Eutrophication (nutrient enrichment) - Government of Western Australia

Eutrophication (nutrient enrichment) - Government of Western Australia

Contextual Support GreyLiterature

Eutrophication (Pollution) - Scotch College Library

Preview of Identifying limitations for invasion: the effect of phosphorus availability on the growth of the non-native tree, Tipuana tipu - CSIRO Publishing

Identifying limitations for invasion: the effect of phosphorus availability on the growth of the non-native tree, Tipuana tipu - CSIRO Publishing

Contextual Support Journal

Identifying limitations for invasion: the effect of phosphorus availability on the growth of the non-native tree, Tipuana tipu - CSIRO Publishing

Preview of Indicative Soil Phosphorus Report | LongPaddock | Queensland Government

Indicative Soil Phosphorus Report | LongPaddock | Queensland Government

Contextual Support Government

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

Preview of management of inland arid and semi-arid woodland ... - DBCA Library, accessed July 12, 2025,

management of inland arid and semi-arid woodland ... - DBCA Library, accessed July 12, 2025,

Contextual Support Journal

management of inland arid and semi-arid woodland ... - DBCA Library, accessed July 12, 2025,

Preview of Multiple adaptive responses of Australian native perennial legumes with pasture potential to grow in phosphorus- and moisture-limited environments

Multiple adaptive responses of Australian native perennial legumes with pasture potential to grow in phosphorus- and moisture-limited environments

Contextual Support Journal

Putting the P in Ptilotus: a phosphorus-accumulating herb native to Australia | Annals of Botany | Oxford Academic

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

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

Preview of Phosphorus sorption in relation to soil properties for the major soil types of South-Western Australia | Request PDF - ResearchGate

Phosphorus sorption in relation to soil properties for the major soil types of South-Western Australia | Request PDF - ResearchGate

Contextual Support Journal

(PDF) Mobility of phosphorus through intact soil cores collected from the Adelaide Hills, South Australia - ResearchGate

Preview of Plant and soil carbon, nitrogen and phosphorus on the Australian continent - CiteSeerX, accessed July 16, 2025,

Plant and soil carbon, nitrogen and phosphorus on the Australian continent - CiteSeerX, accessed July 16, 2025,

Contextual Support GreyLiterature

Soil phosphorus testing: Colwell P and DGT-P - WA Soil Knowledge Base

Preview of Soil factors influencing eutrophication. In Soilguide. A handbook for understanding and managing agricultural soils. (ed. Geoff - DPIRD's Digital library

Soil factors influencing eutrophication. In Soilguide. A handbook for understanding and managing agricultural soils. (ed. Geoff - DPIRD's Digital library

Contextual Support

Soil factors influencing eutrophication. In Soilguide. A handbook for understanding and managing agricultural soils. (ed. Geoff - DPIRD's Digital library

Preview of Soil phosphorus and tree cover modify the effects of livestock grazing on plant species richness in Australian grassy woodland - ResearchGate, accessed August 11, 2025

Soil phosphorus and tree cover modify the effects of livestock grazing on plant species richness in Australian grassy woodland - ResearchGate, accessed August 11, 2025

Contextual Support

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

Preview of Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics, accessed August 11, 2025

Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics, accessed August 11, 2025

Contextual Support Journal

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

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Conservation / Protected Natural Areas
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 2
Effective From 25 Mar 2026

Notes

Less than 1% of native species are predicted to persist at sites with this level of available phosphorus.

Related Benchmarks

Other benchmarks in the AUS-TSW-CON-SOP family.