Soil Phosphorus

AUS-AIF-LVG-SOP General High confidence

Benchmark Value

15 mg/kg
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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

A single value of 15 mg/kg Colwell P is proposed as the benchmark.

Metric Definition:

Colwell P concentration in the top 0-10 cm of soil, representing plant-available phosphorus.

Benchmark Definition:

This benchmark represents a state of high natural fertility and sustainable productivity in the arid inland floodplains biome under best-practice grazing management, balancing livestock needs with native biodiversity preservation.

Justification:

Supported by a functional analysis defining an optimal ecological range of 8–20 mg/kg and the Queensland Government's Available-P map showing the transition from 'Moderate' to 'High' inherent fertility.

Sources (4)

Preview of How Biodiversity-Friendly Is Regenerative Grazing? - Frontiers, accessed July 17, 2025,
How Biodiversity-Friendly Is Regenerative Grazing? - Frontiers, accessed July 17, 2025, Journal

How Biodiversity-Friendly Is Regenerative Grazing? - Frontiers

View Source
Preview of Phosphorus management of beef cattle in northern Australia - MLA, accessed July 17, 2025,
Phosphorus management of beef cattle in northern Australia - MLA, accessed July 17, 2025, Government

Phosphorus management of beef cattle in northern Australia - MLA

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 Journal

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed July 22, 2025

View Source
Preview of Queensland predicted soil bicarbonate-extractable phosphorus - map (Stage 3)
Queensland predicted soil bicarbonate-extractable phosphorus - map (Stage 3) Government

Queensland predicted soil bicarbonate-extractable phosphorus - map (Stage 3)

View Source

Supporting Sources (28)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Soil phosphorus—crop response calibration relationships and criteria for oilseeds, grain legumes and summer cereal crops grown in Australia - ResearchGate, accessed July 17, 2025,
(PDF) Soil phosphorus—crop response calibration relationships and criteria for oilseeds, grain legumes and summer cereal crops grown in Australia - ResearchGate, accessed July 17, 2025,
Contextual Support Journal

(PDF) Soil phosphorus—crop response calibration relationships and criteria for oilseeds, grain legumes and summer cereal crops grown in Australia - ResearchGate

View Source
Preview of A simple phosphorus buffering index for Australian soils - University of Tasmania Open Access Repository Cover sheet
A simple phosphorus buffering index for Australian soils - University of Tasmania Open Access Repository Cover sheet
Contextual Support GreyLiterature

Phosphorus - NSW | Fact Sheets | soilquality.org.au, accessed July 22, 2025

View Source
Preview of Are you on the map? Queensland phosphorus (P) map - MLA, accessed July 17, 2025,
Are you on the map? Queensland phosphorus (P) map - MLA, accessed July 17, 2025,
Direct Evidence Journal

Are you on the map? Queensland phosphorus (P) map - MLA

View Source
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

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

View Source
Preview of BASIC SOIL PROPERTIES - Land Resources and Environmental Sciences, accessed July 17, 2025,
BASIC SOIL PROPERTIES - Land Resources and Environmental Sciences, accessed July 17, 2025,
Contextual Support Journal

BASIC SOIL PROPERTIES - Land Resources and Environmental Sciences

View Source
Preview of Changes in soil carbon in response to flooding of the floodplain of a ..., accessed July 17, 2025
Changes in soil carbon in response to flooding of the floodplain of a ..., accessed July 17, 2025
Contextual Support Government

Floods - Bushland and agriculture - CSIRO

View Source
Preview of Channel Country Region Plant Index - FutureBeef, accessed July 17, 2025,
Channel Country Region Plant Index - FutureBeef, accessed July 17, 2025,
Contextual Support Journal

Channel Country Region Plant Index - FutureBeef

View Source
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

View Source
Preview of Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed August 5, 2025,
Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed August 5, 2025,
Contextual Support GreyLiterature

Regenerative agriculture in Australia: the changing face of farming - Frontiers, accessed July 23, 2025

View Source
Preview of Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 17, 2025,
Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 17, 2025,
Contextual Support Journal

Discover the Top 6 Benefits of Regenerative Farming in Australia

View Source
Preview of Efficiency of soil and fertilizer phosphorus use - Food and Agriculture Organization of the United Nations, accessed July 17, 2025,
Efficiency of soil and fertilizer phosphorus use - Food and Agriculture Organization of the United Nations, accessed July 17, 2025,
Contextual Support Government

Efficiency of soil and fertilizer phosphorus use - Food and Agriculture Organization of the United Nations

View Source
Preview of Improved maps of available phosphorus for the state of Queensland ..., accessed July 17, 2025,
Improved maps of available phosphorus for the state of Queensland ..., accessed July 17, 2025,
Direct Evidence Journal

Updating the Phosphorus Map of Queensland - FutureBeef, accessed July 18, 2025

View Source
Preview of Indicative Soil Phosphorus Report | LongPaddock | Queensland Government
Indicative Soil Phosphorus Report | LongPaddock | Queensland Government
Direct Evidence Government

Indicative Soil Phosphorus Report | LongPaddock | Queensland Government

View Source
Preview of Lake Eyre Basin Rivers Assessment Implementation Plan Project - ResearchGate, accessed July 22, 2025,
Lake Eyre Basin Rivers Assessment Implementation Plan Project - ResearchGate, accessed July 22, 2025,
Contextual Support

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

View Source
Preview of Managing soils - Department of Primary Industries and Regional Development, accessed July 21, 2025,
Managing soils - Department of Primary Industries and Regional Development, accessed July 21, 2025,
Contextual Support Journal

Gilgai wetlands - WetlandInfo

View Source
Preview of P dynamics in vertosols – which soil properties affect declines in P availability over time? Are there differences between MAP, accessed July 17, 2025,
P dynamics in vertosols – which soil properties affect declines in P availability over time? Are there differences between MAP, accessed July 17, 2025,
Contextual Support GreyLiterature

P dynamics in vertosols – which soil properties affect declines in P availability over time? Are there differences between MAP

View Source
Preview of Phosphorus Buffering Index (0 - 10 cm) | South Australia | Examine | soilquality.org.au, accessed July 17, 2025,
Phosphorus Buffering Index (0 - 10 cm) | South Australia | Examine | soilquality.org.au, accessed July 17, 2025,
Contextual Support Government

Phosphorus Buffering Index (0 - 10 cm) | South Australia | Examine | soilquality.org.au

View Source
Preview of Phosphorus dynamics in Vertosols: improving fertilizer management - Agronomy Australia Proceedings, accessed July 17, 2025,
Phosphorus dynamics in Vertosols: improving fertilizer management - Agronomy Australia Proceedings, accessed July 17, 2025,
Contextual Support Journal

Phosphorus dynamics in Vertosols: improving fertilizer management - Agronomy Australia Proceedings

View Source
Preview of phosphorus-fact.pdf - Soil Wealth, accessed July 22, 2025,
phosphorus-fact.pdf - Soil Wealth, accessed July 22, 2025,
Contextual Support Journal

Field benchmarking of the critical external phosphorus requirements of pasture legumes for southern Australia - CSIRO Publishing

View Source
Preview of Queensland predicted soil bicarbonate-extractable phosphorus - map (Stage 3), accessed July 17, 2025,
Queensland predicted soil bicarbonate-extractable phosphorus - map (Stage 3), accessed July 17, 2025,
Contextual Support Government

Queensland predicted soil bicarbonate-extractable phosphorus - map (Stage 3), accessed July 17, 2025,

View Source
Preview of Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed August 5, 2025,
Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed August 5, 2025,
Contextual Support Journal

Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed July 20, 2025,

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,
Contextual Support Government

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

View Source
Preview of Soil testing for phosphorus: comparing the Mehlich 3 and Colwell procedures for soils of south-western Australia | Request PDF - ResearchGate, accessed July 17, 2025,
Soil testing for phosphorus: comparing the Mehlich 3 and Colwell procedures for soils of south-western Australia | Request PDF - ResearchGate, accessed July 17, 2025,
Methodology Source Journal

Soil testing for phosphorus: comparing the Mehlich 3 and Colwell procedures for soils of south-western Australia | Request PDF - ResearchGate

View Source
Preview of The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and Semi-arid American Southwest - Environmental Protection Agency (EPA)
The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and Semi-arid American Southwest - Environmental Protection Agency (EPA)
Contextual Support Journal

The Phosphorus Buffering Index – What Does it Mean for Your Soil? - Summit Fertilizers

View Source
Preview of The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and Semi-arid American Southwest - Environmental Protection Agency (EPA), accessed July 17, 2025,
The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and Semi-arid American Southwest - Environmental Protection Agency (EPA), accessed July 17, 2025,
Contextual Support Journal

The Ecological and Hydrological Significance of Ephemeral and Intermittent Streams in the Arid and Semi-arid American Southwest - Environmental Protection Agency (EPA)

View Source
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.

View Source
Preview of What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed July 17, 2025,
What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed July 17, 2025,
Contextual Support GreyLiterature

What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed July 17, 2025,

View Source
Preview of www.barrierreef.org, accessed on May 25, 2025,
www.barrierreef.org, accessed on May 25, 2025,
Direct Evidence Journal

Regenerative Agriculture Program restoring soil pH case study: Macdonald, Whites Flat/Koppio, accessed July 18, 2025,

View Source

Context

  • Region Australia
  • Biome Arid Inland Floodplains & Ephemeral River Systems
  • Land Use Livestock Grazing & Pasture
  • Assessment Not Stated
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 9 Jun 2026

Notes

Lower Critical Threshold: 8 mg/kg. Upper Detrimental Threshold: 20 mg/kg. The lower threshold marks inadequate phosphorus for sustainable livestock production, while the upper threshold indicates ecological degradation due to displacement of native grasses. Applicable mainly to cracking clay soils (Vertosols) with moderate-to-high Phosphorus Buffering Index (PBI). AssessmentContext defaulted to 'Not Stated' because the source document did not state one.