Soil Organic Carbon (SOC)

AUS-TMI-LVG-SOC General Moderate confidence

Benchmark Value

3.5 %

Direction: Higher is desirable ↑

Form: UpperThreshold

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.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard UpperThreshold Guard

Evidence & Context

For the specific context of this biome and its dominant Ferrosol soils, a lower critical threshold of <1.5% SOC is proposed.

Metric Definition:

Soil Organic Carbon (SOC) content in soil, representing the carbon constituent of Soil Organic Matter.

Benchmark Definition:

This benchmark defines the lower critical soil organic carbon threshold for Ferrosol soils in the Tropical & Subtropical Maritime Islands biome, below which soil stability and ecosystem health are compromised.

Justification:

Below this level, soil stability is compromised, increasing erosion risk, especially for friable Ferrosols in this biome.

Sources (1)

Preview of Soil Carbon Sequestration Potential: A review for Australian agriculture - MLA, accessed August 5, 2025,

Soil Carbon Sequestration Potential: A review for Australian agriculture - MLA, accessed August 5, 2025, Journal

Spatial distribution of soil microbial activity and soil properties ..., accessed August 13, 2025,

View Source

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

Norfolk Island Environmental Assessment

Direct Evidence

Soil Organic Carbon May Decline Under Climate Change: A Case Study in Mexican Forests, accessed July 19, 2025

View Source

Soil Carbon Sequestration Potential: A review for Australian agriculture - MLA

Contextual Support Journal

Potential for soil carbon sequestration in Northern Australian grazing lands: A review of the evidence

View Source

Soil organic matter and carbon sequestration in pastures - FutureBeef, accessed August 5, 2025,

Contextual Support GreyLiterature

A farmer's guide to increasing Soil Organic Carbon under pastures - NSW Department of Primary Industries

View Source

The Soil Carbon Research Program (SCaRP) - CSIROpedia, accessed July 6, 2025,

Contextual Support Government

Mapping soil organic carbon fractions for Australia, their stocks, and uncertainty - BG

View Source

Context

Region Australia
Biome Tropical & Subtropical Maritime Islands
Land Use Livestock Grazing & Pasture
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 19 Mar 2026

Notes

Represents a critical tipping point for soil integrity and ecosystem health in the biome. ConsistencyResolver applied 2026-03-23 00:16 UTC: BenchmarkValue 1.5 → 3.5 (check: MinAboveMax, rationale: Set the MaximumOnly benchmark's value to 3.5 to represent the upper threshold, consistent with the optimal range and ecological interpretation.) ConsistencyResolver applied 2026-03-23 00:16 UTC: LowerThreshold 1.5 → (check: MinAboveMax, rationale: Clear the LowerThreshold as it will no longer be a lower floor after swapping values.)

Related Benchmarks

Other benchmarks in the AUS-TMI-LVG-SOC family.