Soil Phosphorus

AUS-TDG-CON-SOP General Moderate confidence

Benchmark Value

6 mg/kg
Direction: Lower 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 11 benchmarks together — the OptimalRange form drives the primary score, while 10 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Using Olsen P method: A benchmark of <6 mg/kg (0-10 cm depth) is recommended.

Metric Definition:

Available soil phosphorus concentration measured by Olsen P method at 0-10 cm soil depth

Benchmark Definition:

This benchmark defines the maximum soil phosphorus concentration measured by Olsen P method to maintain high conservation value native grass communities in temperate dry woodlands and native grasslands.

Justification:

This value aligns with the requirements for maintaining fertility-intolerant native grass communities, such as those dominated by Themeda triandra, and is supported by Victorian guidelines for healthy native pastures.

Sources (2)

Preview of Phosphorus responses of perennial native pasture species endemic to south-eastern Australia to P application: a review. Crop & Pasture Science, 71(9), 797-815. (Lodge, G. M., Murphy, S. R., & Harden, S., 2020)
Phosphorus responses of perennial native pasture species endemic to south-eastern Australia to P application: a review. Crop & Pasture Science, 71(9), 797-815. (Lodge, G. M., Murphy, S. R., & Harden, S., 2020) Journal

Phosphorus fertiliser management for pastures based on native grasses in south-eastern Australia

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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 Government

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

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Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of Individual plant species responses to phosphorus and livestock grazing in temperate grassy ecosystems of Australia (Dorrough and Scroggie, 2008)
Individual plant species responses to phosphorus and livestock grazing in temperate grassy ecosystems of Australia (Dorrough and Scroggie, 2008)
Contextual Support Journal

Individual plant species responses to phosphorus and livestock grazing in temperate grassy ecosystems of Australia. Australian Journal of Botany, 56(8), 663-673. (Dorrough and Scroggie, 2008)

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Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

Maintaining Olsen P below 6 mg/kg is crucial to avoid detrimental effects such as decline in native species and increased weed invasion.

Related Benchmarks

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

8 mg/kg Low
Conservation / Protected Natural Areas · Conservation Target
Point Active v1