Soil Phosphorus

AUS-ASC-FOR-SOP General Low confidence

Benchmark Value

50 mg/kg
Direction: Higher 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 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard MinimumOnly Guard MaximumOnly Guard Point Guard

Evidence & Context

Persistent elevation of available P significantly above the natural optimal range, potentially exceeding 50-100 mg/kg, due to artificial inputs, would be a concern.

Metric Definition:

Available phosphorus (Colwell P or Olsen P)

Benchmark Definition:

This benchmark marks the upper threshold of available phosphorus in production forestry soils, above which nutrient imbalances and ecological harm may occur.

Justification:

Excessive P can lead to nutrient imbalances, toxicity to sensitive native species, and off-site nutrient pollution.

Supporting Sources (22)

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 GreyLiterature

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC

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

P.V. Woods & R.J. Raison. (1983). Losses of nitrogen during prescribed burning in a Eucalyptus pauciflora forest.

View Source
Preview of Doolette, A. L., et al. (2009). Speciation of organic phosphorus in soil. EST. []
Doolette, A. L., et al. (2009). Speciation of organic phosphorus in soil. EST. []
Contextual Support Journal

Doolette, A. L., et al. (2009). Speciation of organic phosphorus in soil. EST. []

View Source
Preview of Effects of soil phosphorus availability on soil respiration in Eucalyptus pauciflora forest
Effects of soil phosphorus availability on soil respiration in Eucalyptus pauciflora forest
Contextual Support Journal

Effects of soil phosphorus availability on soil respiration in Eucalyptus pauciflora forest

View Source
Preview of Global patterns and drivers of soil total phosphorus concentration - ESSD Copernicus, accessed on May 31, 2025
Global patterns and drivers of soil total phosphorus concentration - ESSD Copernicus, accessed on May 31, 2025
Direct Evidence Journal

Global patterns and drivers of soil total phosphorus concentration - ESSD Copernicus

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

Soil nutrient critical limits | MBFP | More Beef from Pastures, accessed July 22, 2025

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

Understanding Ecohydrological and Biogeochemical Processes in ...

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

Soil nutrient status in different forest types

View Source
Preview of McLaren, T. I., Smernik, R. J., McLaughlin, M. J., McBeath, T. M., & Bunemann, E. K. (2017). Climate is a key driver in the variation of organic P speciation in soils. Soil Research, 55(1), 23-33.
McLaren, T. I., Smernik, R. J., McLaughlin, M. J., McBeath, T. M., & Bunemann, E. K. (2017). Climate is a key driver in the variation of organic P speciation in soils. Soil Research, 55(1), 23-33.
Contextual Support Government

McLaren, T. I., Smernik, R. J., McLaughlin, M. J., McBeath, T. M., & Bunemann, E. K. (2017). Climate is a key driver in the variation of organic P speciation in soils. Soil Research, 55(1), 23-33.

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

Nutrition and management of Acacia plantations

View Source
Preview of National Soil Action Plan - DAFF, accessed August 11, 2025,
National Soil Action Plan - DAFF, accessed August 11, 2025,
Direct Evidence Journal

Australian Government. (2023). National Soil Action Plan 2023 to 2028. Department of Agriculture, Fisheries and Forestry.

View Source
Preview of Patterns of variation in Australian alpine soils and their relationships to parent material, vegetation formation, climate and topography | Request PDF - ResearchGate, accessed August 3, 2025,
Patterns of variation in Australian alpine soils and their relationships to parent material, vegetation formation, climate and topography | Request PDF - ResearchGate, accessed August 3, 2025,
Direct Evidence Journal

Water infiltration rate as affected by grazing land management ...

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

The Ridgefield Multiple Ecosystem Services Experiment

View Source
Preview of Proceedings of the 20th Australasian Weeds Conference
Proceedings of the 20th Australasian Weeds Conference
Contextual Support GreyLiterature

Proceedings of the 20th Australasian Weeds Conference

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

Keith, H. (1997). Effects of soil phosphorus availability, temperature, and moisture on soil respiration in Eucalyptus pauciflora forest. Plant and Soil, 190(1), 121-141. []

View Source
Preview of SOC and total N in three successional forests
SOC and total N in three successional forests
Contextual Support Journal

SOC and total N in three successional forests

View Source
Preview of Soil properties and plant traits in a Tasmanian environmental gradient
Soil properties and plant traits in a Tasmanian environmental gradient
Direct Evidence Journal

Management of Eucalyptus grandis seedlings

View Source
Preview of Speciation of organic P in soil extracts
Speciation of organic P in soil extracts
Contextual Support Journal

McLaren, T. I., Smernik, R. J., Guppy, C. N., & Bell, M. J. (2015). Speciation of organic phosphorus in soil extracts fractionated into two molecular weight ranges. Environmental Science & Technology, 49(21), 12648-12655. []

View Source
Preview of Sustainable Timber Tasmania. (2025). Silvicultural use and effects of fire. Technical Bulletin 11.
Sustainable Timber Tasmania. (2025). Silvicultural use and effects of fire. Technical Bulletin 11.
Direct Evidence

Sustainable Timber Tasmania. (2025). Silvicultural use and effects of fire. Technical Bulletin 11.

View Source
Preview of Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics, accessed August 11, 2025
Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics, accessed August 11, 2025
Contextual Support Journal

Too much of a good thing: phosphorus over-fertilisation in rehabilitated landscapes of high biodiversity value - Australian Centre for Geomechanics

View Source
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,
Direct Evidence Government

What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed July 18, 2025

View Source
Preview of Why phosphorus is important - NSW Department of Primary Industries, accessed August 4, 2025
Why phosphorus is important - NSW Department of Primary Industries, accessed August 4, 2025
Direct Evidence Government

Why phosphorus is important - NSW Department of Primary Industries

View Source

Context

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

Lifecycle

  • Status Superseded
  • Version 1
  • Effective From 3 Jun 2026
  • Effective To 3 Jun 2026

Notes

Range given as 50-100 mg/kg; 50 used as the lower bound of the detrimental zone.

Related Benchmarks

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

50 mg/kg Low
Production Forestry · Production Forestry
MaximumOnly Active v3
5 mg/kg Low
Production Forestry · mineral soils
MinimumOnly Active v2
5 mg/kg Low
Production Forestry · Not Stated
MinimumOnly Active v1
28.9 mg/kg Low
Production Forestry · Not Stated
Point Active v1
— mg/kg Low
Production Forestry · unmanaged alpine/sub-alpine soils on gneissic granite
OptimalRange Active v1
50 mg/kg Low
Production Forestry · Production Forestry
MaximumOnly Superseded v2
5 mg/kg Low
Production Forestry · mineral soils
MinimumOnly Superseded v1