Soil Organic Carbon (SOC)

AUS-TSR-CON-SOC General High confidence

Benchmark Value

3.2 %

Range: 3 to 4 %

Optimal Range: 3 to 4

Direction: Higher is desirable ↑

Form: Point

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 2 benchmarks together — the Point form drives the primary score, while 1 guard(s) constrain the result.

Contributing Benchmarks

Point Primary MinimumOnly Guard

Evidence & Context

Based on a synthesis of the available evidence, a benchmark value of 3.2% SOC is proposed for the 0 cm soil layer in Australian Tropical and Subtropical Rainforests under conservation management.

Metric Definition:

Soil Organic Carbon concentration in the 0 cm soil layer

Benchmark Definition:

Soil Organic Carbon concentration in the 0 cm soil layer as a benchmark for ecosystem health in conservation areas of Australian Tropical & Subtropical Rainforests.

Justification:

This value is selected for several reasons: direct measurement in primary tropical forest, corroboration by other high-functioning systems, and represents a general condition for typical loamy soils.

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

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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

CRITICAL SOIL ORGANIC CARBON RANGE FOR OPTIMAL CROP RESPONSE TO MINERAL FERTILISER NITROGEN ON A FERRALSOL | Experimental Agriculture - Cambridge University Press

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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 ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 21 Mar 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. SOC potential is strongly controlled by soil texture and geology. Texture-differentiated benchmarks are recommended: ~2.0% for sandy soils, 3.2% for loamy soils, and ~6.6% for fertile basalt-derived clayey soils.

Related Benchmarks

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