Soil Phosphorus

AUS-TGP-FOR-SOP General High confidence

Benchmark Value

5 mg/kg
Thresholds: Lower: 5, Upper: —
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 3 benchmarks together — the OptimalRange form drives the primary score, while 2 guard(s) constrain the result.

Evidence & Context

A soil available phosphorus level below 5 mg/kg is considered critically low for maintaining the essential functions and long-term productivity of a sustainable production forestry system in this biome.

Metric Definition:

Available soil phosphorus level below which forest productivity and ecological function are significantly compromised.

Benchmark Definition:

Represents a state of clear nutrient deficiency where long-term productivity and site health are compromised in temperate grassy woodlands production forestry.

Justification:

Based on controlled experiments showing significant growth limitation in Eucalyptus species at available P levels of approximately 4.5 mg/kg.

Sources (1)

Preview of Establishment of critical nutrient levels in soil and plant for eucalyptus
Establishment of critical nutrient levels in soil and plant for eucalyptus Journal

Establishment of critical nutrient levels in soil and plant for eucalyptus

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Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Preview of Phosphorus Nutrition of Proteaceae in Severely Phosphorus-Impoverished Soils: Are There Lessons To Be Learned for Future Crops? - PubMed Central, accessed August 4, 2025
Phosphorus Nutrition of Proteaceae in Severely Phosphorus-Impoverished Soils: Are There Lessons To Be Learned for Future Crops? - PubMed Central, accessed August 4, 2025
Contextual Support Journal

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

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Preview of Phosphorus uptake and toxicity are delimited by mycorrhizal symbiosis in P-sensitive Eucalyptus marginata but not in P-tolerant Acacia celastrifolia - PubMed Central
Phosphorus uptake and toxicity are delimited by mycorrhizal symbiosis in P-sensitive Eucalyptus marginata but not in P-tolerant Acacia celastrifolia - PubMed Central
Contextual Support Journal

Phosphorus uptake and toxicity are delimited by mycorrhizal symbiosis in P-sensitive Eucalyptus marginata but not in P-tolerant Acacia celastrifolia - PubMed Central

View Source

Context

  • Region Australia
  • Biome Temperate Grassy Woodlands & Plains
  • Land Use Production Forestry
  • Assessment Conservation Target
  • Vegetation Forest
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 24 Mar 2026

Notes

Operating a plantation below this threshold suggests a state of chronic nutrient deficiency where the system's productive capacity is severely constrained.