Soil Phosphorus

AUS-TMI-AGR-SOP General High confidence

Benchmark Value

70 mg/kg
Thresholds: Lower: —, Upper: 70
Direction: Lower 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 12 benchmarks together — the OptimalRange form drives the primary score, while 11 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Exceeding an available phosphorus level of 70 mg/kg is not a sign of high fertility but rather an indicator of mismanagement and a degraded ecological state.

Metric Definition:

Available phosphorus level in soil above which ecological degradation and environmental risks occur.

Benchmark Definition:

Upper detrimental threshold for available phosphorus indicating ecological harm.

Justification:

Above this level, phosphorus accumulation disrupts soil biology and poses significant risk of nutrient leaching and runoff causing eutrophication.

Sources (1)

Preview of AGRICULTURAL AUDIT & LAND USE CAPABILITY ASSESSMENT ..., accessed July 30, 2025,
AGRICULTURAL AUDIT & LAND USE CAPABILITY ASSESSMENT ..., accessed July 30, 2025, Journal

Norfolk Island Agricultural Audit and Land Capability Assessment Report

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of NORFOLK ISLAND FOOD SECURITY STRATEGY 2023 - 2028 “Growing the local food economy for a resilient, sustainable and healthy com, accessed July 25, 2025,
NORFOLK ISLAND FOOD SECURITY STRATEGY 2023 - 2028 “Growing the local food economy for a resilient, sustainable and healthy com, accessed July 25, 2025,
Contextual Support Journal

NORFOLK ISLAND FOOD SECURITY STRATEGY 2023 - 2028 “Growing the local food economy for a resilient, sustainable and healthy com

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Maritime Islands
  • Land Use Agricultural Crop Production
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

Suppresses beneficial mycorrhizal fungi and leads to pollution of sensitive marine ecosystems.

Related Benchmarks

Other benchmarks in the AUS-TMI-AGR-SOP family.

— mg/kg High
Agricultural Crop Production · Pristine Reference
OptimalRange Active v1
30 mg/kg High
Agricultural Crop Production · Pristine Reference
MinimumOnly Active v1