Soil Phosphorus

AUS-AKW-AGR-SOP General Moderate confidence

Benchmark Value

6 mg/kg
Thresholds: Lower: 6, Upper: —
Direction: Higher is desirable ↑
Form: LowerThreshold

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 12 benchmarks together — the OptimalRange form drives the primary score, while 11 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary LowerThreshold Guard UpperThreshold Guard Point Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard OptimalRange Guard OptimalRange Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard

Evidence & Context

Lower Critical Threshold: < 6 mg/kgBelow this level, available phosphorus is highly likely to be the primary factor limiting crop growth, even in a biologically active soil.

Metric Definition:

Available soil phosphorus measured as Colwell-P

Benchmark Definition:

This benchmark represents the minimum soil phosphorus level below which crop growth is likely limited, compromising agricultural productivity in the Arid Karstic Woodlands & Shrublands biome under agricultural crop production.

Justification:

This threshold is derived from the "Very Low" category in soil fertility guides and represents the point below which agricultural function is not sustainable.

Sources (1)

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

Supporting Sources (25)

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 Health Assessment of Two Regenerative Farming Practices on Sandy Soils, accessed July 22, 2025,
(PDF) Soil Health Assessment of Two Regenerative Farming Practices on Sandy Soils, accessed July 22, 2025,
Contextual Support

Soil Mapping Mulloon Creek Catchment - Research project - - Squarespace, accessed July 22, 2025,

View Source
Preview of (PDF) Soil phosphorus—crop response calibration relationships and ..., accessed August 4, 2025
(PDF) Soil phosphorus—crop response calibration relationships and ..., accessed August 4, 2025
Contextual Support

Soil nutrient critical limits | MBFP | More Beef from Pastures, accessed July 21, 2025,

View Source
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, accessed August 5, 2025,

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

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

View Source
Preview of Ch 19. Management of Nitrogen and Phosphorus - SARE, accessed July 22, 2025,
Ch 19. Management of Nitrogen and Phosphorus - SARE, accessed July 22, 2025,
Contextual Support GreyLiterature

Ch 19. Management of Nitrogen and Phosphorus - SARE, accessed July 22, 2025,

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

The relationships between land management practices and soil condition and the quality of ecosystem services delivered from agri - DAFF

View Source
Preview of Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 22, 2025,
Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 22, 2025,
Contextual Support GreyLiterature

Discover the Top 6 Benefits of Regenerative Farming in Australia, accessed July 22, 2025,

View Source
Preview of Ecology of Australia: the effects of nutrient-poor soils and intense fires - PubMed, accessed August 11, 2025,
Ecology of Australia: the effects of nutrient-poor soils and intense fires - PubMed, accessed August 11, 2025,
Contextual Support Journal

Ecology of Australia: the effects of nutrient-poor soils and intense fires - PubMed

View Source
Preview of Fact Sheets Chemical Indicators - Soil Quality, accessed August 5, 2025,
Fact Sheets Chemical Indicators - Soil Quality, accessed August 5, 2025,
Contextual Support GreyLiterature

Phosphorus Forms and Functions - Soil Management, accessed July 22, 2025,

View Source
Preview of Great Western Woodlands SuperSite | Climate Change Impacts - TERN Australia, accessed July 10, 2025,
Great Western Woodlands SuperSite | Climate Change Impacts - TERN Australia, accessed July 10, 2025,
Contextual Support GreyLiterature

URBAN FOREST STRATEGY - Your Say South Perth, accessed July 13, 2025

View Source
Preview of Indicative Soil Phosphorus Report | LongPaddock | Queensland ..., accessed July 22, 2025,
Indicative Soil Phosphorus Report | LongPaddock | Queensland ..., accessed July 22, 2025,
Contextual Support Government

Indicative Soil Phosphorus Report | LongPaddock | Queensland ..., accessed July 22, 2025,

View Source
Preview of Inherent Factors Affecting Soil Phosphorus - USDA, accessed July 22, 2025,
Inherent Factors Affecting Soil Phosphorus - USDA, accessed July 22, 2025,
Contextual Support Journal

Inherent Factors Affecting Soil Phosphorus - USDA, accessed July 22, 2025,

View Source
Preview of Landscape rehydration and regenerative agriculture improves soil health, accessed July 22, 2025,
Landscape rehydration and regenerative agriculture improves soil health, accessed July 22, 2025,
Contextual Support GreyLiterature

Landscape rehydration and regenerative agriculture improves soil health, accessed July 22, 2025,

View Source
Preview of Landscape rehydration and regenerative agriculture improves soil health, accessed July 30, 2025,
Landscape rehydration and regenerative agriculture improves soil health, accessed July 30, 2025,
Contextual Support GreyLiterature

Soil Health and Regenerative Agriculture - Southern Queensland Landscapes, accessed July 27, 2025,

View Source
Preview of Nullarbor Plains Xeric Shrublands | One Earth, accessed July 26, 2025,
Nullarbor Plains Xeric Shrublands | One Earth, accessed July 26, 2025,
Contextual Support

State Soils - Soil Science Australia

View Source
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

Soil tests, accessed August 5, 2025,

View Source
Preview of Phosphorus Dynamics: From Soil to Plant - PMC, accessed July 22, 2025,
Phosphorus Dynamics: From Soil to Plant - PMC, accessed July 22, 2025,
Contextual Support GreyLiterature

(PDF) The Nature of Phosphorus in Calcareous Soils - ResearchGate, accessed July 22, 2025,

View Source
Preview of Phosphorus Loss from Land to Water: Integrating Agricultural and Environmental Management - ResearchGate
Phosphorus Loss from Land to Water: Integrating Agricultural and Environmental Management - ResearchGate
Contextual Support Journal

Recovery of soil and vegetation in semi-arid Australian old fields - ResearchGate, accessed July 22, 2025,

View Source
Preview of Phosphorus nutrition of Australian Proteaceae and Cyperaceae: A strategy on old landscapes with prolonged oceanically buffered climates - ResearchGate, accessed July 22, 2025,
Phosphorus nutrition of Australian Proteaceae and Cyperaceae: A strategy on old landscapes with prolonged oceanically buffered climates - ResearchGate, accessed July 22, 2025,
Contextual Support GreyLiterature

Phosphorus nutrition of Australian Proteaceae and Cyperaceae: A strategy on old landscapes with prolonged oceanically buffered climates - ResearchGate, accessed July 22, 2025,

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

Field benchmarking of the critical external phosphorus requirements of pasture legumes for southern Australia - CSIRO Publishing, accessed July 17, 2025,

View Source
Preview of Regenerative agriculture is key to dry season preparation - Soils For Life, accessed July 22, 2025,
Regenerative agriculture is key to dry season preparation - Soils For Life, accessed July 22, 2025,
Contextual Support

Regenerative agriculture is key to dry season preparation - Soils For Life, accessed July 22, 2025,

View Source
Preview of Regenerative opportunities for building soil biological resilience – a ..., accessed May 11, 2025
Regenerative opportunities for building soil biological resilience – a ..., accessed May 11, 2025
Contextual Support GreyLiterature

Soil and fertilizer phosphorus: Effects on plant P supply and mycorrhizal development - Canadian Science Publishing, accessed August 28, 2025

View Source
Preview of Some Characteristics of Calcareous soils. A review A.S. Taalab1, G.W. Ageeb2, Hanan S. Siam1 and Safaa A. Mahmoud1 - CURRENT RESEARCH WEB, accessed July 22, 2025,
Some Characteristics of Calcareous soils. A review A.S. Taalab1, G.W. Ageeb2, Hanan S. Siam1 and Safaa A. Mahmoud1 - CURRENT RESEARCH WEB, accessed July 22, 2025,
Contextual Support

The Nature of Phosphorus in Calcareous Soils - USDA, accessed July 22, 2025,

View Source
Preview of Why phosphorus is important - NSW Department of Primary Industries, accessed July 22, 2025,
Why phosphorus is important - NSW Department of Primary Industries, accessed July 22, 2025,
Contextual Support Government

Why phosphorus is important - NSW Department of Primary Industries, accessed July 22, 2025,

View Source

Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Agricultural Crop Production
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 19 Mar 2026

Notes

Below this level, available phosphorus is highly likely to be the primary factor limiting crop growth, even in a biologically active soil.

Related Benchmarks

Other benchmarks in the AUS-AKW-AGR-SOP family.

— mg/kg Moderate
Agricultural Crop Production · Pristine Reference
OptimalRange Active v1
25 mg/kg Moderate
Agricultural Crop Production · Pristine Reference
UpperThreshold Active v1