Soil Organic Carbon (SOC)

AUS-TSR-CON-SOC General Moderate confidence

Benchmark Value

No specific value — see range

Range: 3 to 4 %

Optimal Range: 3 to 4

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 3 benchmarks together — the OptimalRange form drives the primary score, while 2 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MinimumOnly Guard

Evidence & Context

The optimal range for SOC is best defined as the range of values observed across a set of healthy, mature, reference sites for a given soil type. This range is centered on the benchmark value. For example, for a loamy soil with a benchmark of 3.2%, the optimal range could be considered 3.0% to 4.0%.

Metric Definition:

Range of Soil Organic Carbon (SOC) concentration in the 0–10 cm soil layer representing natural variation in healthy, mature rainforest reference sites.

Benchmark Definition:

Optimal functional range of SOC concentration in loamy soils representing healthy ecosystem conditions.

Justification:

This range represents the natural variation around the benchmark value observed in healthy, mature reference sites.

Sources (1)

Soil carbon distribution and its temperature sensitivity in tropical forests with different forest types Journal

Soil carbon distribution and its temperature sensitivity in tropical forests with different forest types

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Addressing the rundown of nitrogen and soil organic carbon - GRDC, accessed July 25, 2025,

Degradation Threshold Journal

Soil | Australia state of the environment 2021

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Nutrient relationships of tree species in a New South Wales Subtropical rainforest

Contextual Support Journal

Nutrient relationships of tree species in a New South Wales Subtropical rainforest

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Soil Organic Carbon Distribution, Enzyme Activities, and the ... - MDPI

Contextual Support Journal

Soil Organic Carbon Distribution, Enzyme Activities, and the ... - MDPI

View Source

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type HealthyOperationalRange

Lifecycle

Status Active
Version 1
Effective From 6 Jun 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. Sites with SOC levels within this range demonstrate excellent ecological health and meet conservation objectives. The value range (3.0% to 4.0%) is presented as an example ('could be considered') in the source text rather than a stated benchmark. This may be a synthetic derivation.

Related Benchmarks

Other benchmarks in the AUS-TSR-CON-SOC family.