Soil Phosphorus

AUS-TSR-CON-SOP General Moderate confidence

Benchmark Value

No specific value — see range
Range: 1100 to 1700 mg/kg
Optimal Range: 1100 to 1700
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.

Evidence & Context

Total P Benchmark: Data from two key sites provide a consistent range. The subtropical rainforest at Wiangaree State Forest in NSW shows a mean Total P of 1130 - 1365 mg/kg in the upper soil profile. The alluvial soil at the Broadwater site in North Queensland has a mean Total P of~1680 mg/kg. Together, these sites support a composite benchmark range for Total P of - 1700 mg/kg.

Metric Definition:

Total Phosphorus (Total P): This measures the entire stock of phosphorus in the soil, including mineral, organic, and occluded forms.

Benchmark Definition:

This benchmark represents the total phosphorus stock in fertile alluvial and metamorphic soils supporting subtropical rainforest ecosystems in Australia.

Justification:

These sites support a composite benchmark range for Total P of 1100 - 1700 mg/kg.

Sources (2)

Preview of Nutrient relationships of tree species in a New South Wales Subtropical rainforest (Turner & Lambert 1990)
Nutrient relationships of tree species in a New South Wales Subtropical rainforest (Turner & Lambert 1990) GreyLiterature

Tool 2.8: Soil nutrient critical limits (Meat & Livestock Australia 2020)

View Source
Preview of Plant-soil nutrient relationships in the wet tropical rainforests of north Queensland, Australia (Maycock 1998)
Plant-soil nutrient relationships in the wet tropical rainforests of north Queensland, Australia (Maycock 1998) Journal

Plant-soil nutrient relationships in the wet tropical rainforests of north Queensland, Australia (Maycock 1998)

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Rainforests
  • Land Use Conservation / Protected Natural Areas
  • Assessment Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 25 Mar 2026

Notes

These soils, found in fertile river valleys and on certain metamorphic geologies, support robust rainforests and represent a state of high, but not extreme, fertility. No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

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

100 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
Point Active v2
10 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
MinimumOnly Active v1
20 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Active v1
60 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Active v1
— mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
OptimalRange Active v1
3030 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
Point Active v1
1300 mg/kg Moderate
Conservation / Protected Natural Areas · Pristine Reference
Point Superseded v1