Soil Phosphorus

AUS-ASC-FOR-SOP General Low confidence

Benchmark Value

5 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.

Evidence & Context

A Lower Critical Threshold for available phosphorus (e.g., Colwell P or Olsen P) is likely below 5 mg/kg in mineral soils, a level at which seedling establishment, growth, and overall forest vigor may be significantly compromised.

Metric Definition:

Available phosphorus (Colwell P or Olsen P)

Benchmark Definition:

This benchmark marks the lower critical threshold of available phosphorus in mineral soils below which forest regeneration and growth are significantly impaired.

Justification:

Values below 5 mg/kg signify critical deficiency for regeneration and early stand vigor.

Sources (1)

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 Journal

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

Supporting Sources (21)

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

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.

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. []

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

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

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

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 ...

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

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.

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

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.

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 ...

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

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

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. []

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

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

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. []

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.

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

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

Context

Region Australia
Biome Alpine and Subalpine Complex
Land Use Production Forestry
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 3 Jun 2026

Notes

Based on E. obliqua mineral soil <2 mg/kg Colwell P with poor growth. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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