Soil Nitrogen — Benchmark Detail

Benchmark Value

2500 mg/kg

Thresholds: Lower: —, Upper: 2500

Direction: Lower is desirable ↓

Form: MinimumOnly

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 OptimalRange form drives the primary score, while 1 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard

Evidence & Context

The critical upper detrimental threshold is identified as a TN level consistently exceeding 2500 mg/kg.

Metric Definition:

Total Soil Nitrogen (TN) in the top 10 cm of soil

Benchmark Definition:

This benchmark defines the critical upper detrimental threshold for Total Soil Nitrogen in the top 10 cm of soil, above which the ecosystem is at risk of transitioning to a degraded state dominated by exotic species.

Justification:

A TN level consistently above 2500 mg/kg, associated with available nitrate >5 mg/kg, indicates a degraded state dominated by invasive annuals.

Sources (1)

Preview of Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states

Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states

Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states

View Source

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Soil and Landscape Grid National Soil Attribute Maps - Total Nitrogen (3" resolution) - Release 2

Contextual Support Journal

Soil and Landscape Grid National Soil Attribute Maps - Total Nitrogen (3" resolution) - Release 2

View Source

Soil and Landscape Grid National Soil Attribute Maps - Total Nitrogen (3" resolution) - Release 2 - CSIRO Data Access Portal, accessed August 5, 2025,

Contextual Support Government

Geology | Norfolk Island National Park | Parks Australia, accessed August 2, 2025

View Source

Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 25 Mar 2026

Notes

Upper Detrimental Threshold: A TN level consistently above 2500 mg/kg, associated with available nitrate >5 mg/kg, indicates a degraded state dominated by invasive annuals.

Related Benchmarks

Other benchmarks in the AUS-TGP-CON-SON family.