Soil Phosphorus

AUS-ASC-FOR-SOP General Moderate confidence

Benchmark Value

8 mg/kg
Direction: Higher is desirable ↑
Form: MinimumOnly

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 16 benchmarks together — the OptimalRange form drives the primary score, while 15 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

"Olsen P values below 8 mg/kg are considered 'Low'"

Metric Definition:

Olsen P

Benchmark Definition:

Critical minimum Olsen phosphorus below which the system is nutrient-depleted in subalpine production forestry.

Justification:

Olsen P values below 8 mg/kg are considered 'Low' indicating nutrient depletion.

Sources (1)

Preview of What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed August 5, 2025,
What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed August 5, 2025, Government

Scanlan, C. A., et al. (2013). Soil Quality: 10 Plant Nutrition. CCMA Soil Health Knowledge Base.

View Source

Supporting Sources (8)

Additional references from the underlying research that informed this benchmark.

Preview of Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 28, 2025,
Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 28, 2025,
Direct Evidence Journal

Ryan, M. H., & Kirkegaard, J. A. (2012). The agronomic relevance of arbuscular mycorrhizas in the fertility of Australian extensive cropping systems. Agriculture, Ecosystems & Environment.

View Source
Preview of Bowd, E. J., et al. (2019). Wildfire severity and soil nutrient depletion. Journal of Applied Ecology.
Bowd, E. J., et al. (2019). Wildfire severity and soil nutrient depletion. Journal of Applied Ecology.
Contextual Support Journal

Bowd, E. J., et al. (2019). Wildfire severity and soil nutrient depletion. Journal of Applied Ecology.

View Source
Preview of He, X., et al. (2021). Global distribution and influencing factors of plant‐available phosphorus in semi‐natural soils. Earth System Science Data.
He, X., et al. (2021). Global distribution and influencing factors of plant‐available phosphorus in semi‐natural soils. Earth System Science Data.
Direct Evidence

He, X., et al. (2021). Global distribution and influencing factors of plant‐available phosphorus in semi‐natural soils. Earth System Science Data.

View Source
Preview of Kirkpatrick, J. B., and M. J. Brown. 1984. The Tasmanian alpine ecosystem.
Kirkpatrick, J. B., and M. J. Brown. 1984. The Tasmanian alpine ecosystem.
Direct Evidence Journal

Doolette, A. L., Smernik, R. J., & Dougherty, W. J. (2014). Phosphorus speciation in Australian alpine and sub-alpine soils. Soil Research, 54(1), 18-27.

View Source
Preview of Liu, J., et al. (2023). Soil nutrient status and stoichiometry in different forest types. Forests.
Liu, J., et al. (2023). Soil nutrient status and stoichiometry in different forest types. Forests.
Contextual Support Journal

Liu, J., et al. (2023). Soil nutrient status and stoichiometry in different forest types. Forests.

View Source
Preview of Mendham, D. S., et al. (2019). Nutrition and management of Acacia plantations. Australian Forestry.
Mendham, D. S., et al. (2019). Nutrition and management of Acacia plantations. Australian Forestry.
Direct Evidence

Mendham, D. S., et al. (2019). Nutrition and management of Acacia plantations. Australian Forestry.

View Source
Preview of Perring, M. P., et al. (2012). The Ridgefield Multiple Ecosystem Services Experiment: Can restoration of former agricultural land achieve multiple outcomes? Agriculture, Ecosystems & Environment.
Perring, M. P., et al. (2012). The Ridgefield Multiple Ecosystem Services Experiment: Can restoration of former agricultural land achieve multiple outcomes? Agriculture, Ecosystems & Environment.
Direct Evidence

Perring, M. P., et al. (2012). The Ridgefield Multiple Ecosystem Services Experiment: Can restoration of former agricultural land achieve multiple outcomes? Agriculture, Ecosystems & Environment.

View Source
Preview of Selected climatic, chemical and physical properties of the soils used in this study (Table 1)
Selected climatic, chemical and physical properties of the soils used in this study (Table 1)
Contextual Support Journal

Selected climatic, chemical and physical properties of the soils used in this study (Table 1)

View Source

Context

  • Region Australia
  • Biome Alpine and Subalpine Complex
  • Land Use Production Forestry
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

Other benchmarks in the AUS-ASC-FOR-SOP family.

— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Active v2
39.77 mg/kg High
Production Forestry · Pristine Reference
Point Active v2
2 mg/kg Moderate
Production Forestry · Pristine Reference
LowerThreshold Active v1
524 mg/kg High
Production Forestry · Pristine Reference
Point Active v1
565 mg/kg High
Production Forestry · Pristine Reference
Point Active v1
479 mg/kg High
Production Forestry · Pristine Reference
Point Active v1
4.1 mg/kg Moderate
Production Forestry · Pristine Reference
Point Proposed v3
12.4 mg/kg Moderate
Production Forestry · Pristine Reference
Point Proposed v3
30 mg/kg Moderate
Production Forestry · Pristine Reference
Point Proposed v3
— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Superseded v1
9 mg/kg Moderate
Production Forestry · Pristine Reference
Point Superseded v1