Soil Phosphorus

AUS-TSW-LVG-SOP General High confidence

Benchmark Value

No specific value — see range

Range: 10 to 20 mg/kg

Optimal Range: 10 to 20

Direction: Higher is desirable ↑

Form: OptimalRange

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 2 benchmarks together — the OptimalRange form drives the primary score, while 1 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard

Evidence & Context

The optimal range for a healthy ecological state under grazing is the carefully managed band between the lower critical threshold for system viability and the upper detrimental threshold for biodiversity.

Metric Definition:

Available phosphorus (Colwell-P) concentration in soil

Benchmark Definition:

This benchmark defines the optimal ecological range of available phosphorus in soil to maintain ecological health in temperate semi-arid grazing systems with low PBI soils (sands).

Justification:

This range is invariably narrower and sits at a lower absolute level than the range targeted for purely agronomic optimisation.

Sources (1)

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, Journal

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

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

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 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

View Source

Indicative Soil Phosphorus Report | LongPaddock | Queensland Government

Contextual Support Government

Indicative Soil Phosphorus Report | LongPaddock | Queensland Government

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Livestock Grazing & Pasture
Assessment Not Stated
Evidence Type HealthyOperationalRange

Lifecycle

Status Active
Version 1
Effective From 10 Jun 2026

Notes

The optimal range is a narrow band between the lower productive threshold and the upper ecological threshold (e.g., 10-20 mg/kg for low PBI soils). AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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