Soil Organic Carbon (SOC)

AUS-TMI-CON-SOC General Moderate confidence

Benchmark Value

No specific value — see range
Range: 0.3 to 5.3 %
Optimal Range: 0.3 to 5.3
Direction: Higher is desirable ↑
Form: OptimalRange

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 6 benchmarks together — the OptimalRange form drives the primary score, while 5 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard OptimalRange Guard Point Guard LowerThreshold Guard OptimalRange Guard

Evidence & Context

Final Formatted Benchmark Indicator Name: Soil Organic Carbon (SOC) Reference Value: 0.3 – 5.3 Unit: % Source Title: Soil and Land Suitability of the Whitsunday Coast area, Central Queensland Confidence Level: Moderate

Metric Definition:

Soil Organic Carbon (SOC) percentage in the topsoil (0–10 cm) under natural vegetation in conservation areas of the Tropical & Subtropical Maritime Islands biome.

Benchmark Definition:

This benchmark represents the typical range of Soil Organic Carbon percentage in the topsoil under natural vegetation in conservation areas of the Tropical & Subtropical Maritime Islands biome, reflecting variation by soil type and parent material.

Justification:

This benchmark is a proxy derived from an extensive soil survey of the adjacent Whitsunday Coast, which is ecologically and geologically representative. The reference value is presented as a range (0.3% to 5.3%) because the "best available condition" is strongly dependent on soil type and parent material.

Sources (1)

Preview of Soil and Land Suitability of the Whitsunday Coast area, Central Queensland
Soil and Land Suitability of the Whitsunday Coast area, Central Queensland Journal

Soil and Land Suitability of the Whitsunday Coast area, Central Queensland

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Maritime Islands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 19 Mar 2026

Notes

No direct field data for SOC in conservation areas on Australian tropical/subtropical islands was found. High values (> 3.0%) are typical for soils on volcanic and clay-rich alluvial parent materials, while low values (< 1.0%) are characteristic of sandy soils on consolidated sediments. Lower Critical Threshold: A universal threshold is inappropriate; degradation is best defined as a significant decline (e.g., 40–60%) from the soil-type-specific benchmark. Upper Boundary: No evidence supports a detrimental upper threshold in natural ecosystems. The upper limit is the natural carbon saturation point, represented by the benchmark value for a given soil type. Optimal Range: The optimal range for a specific site is from a resilient state (e.g., >60% of its benchmark) up to its full benchmark value.