Soil Nitrogen — Benchmark Detail

Benchmark Value

1200 mg/kg

Range: 900 to 1600 mg/kg

Thresholds: Lower: 300, Upper: 2000

Optimal Range: 900 to 1600

Direction: Lower 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.

Evidence & Context

The benchmark represents the median total nitrogen in topsoil (0-15 cm) for high-health conservation areas. Values are stratified by texture due to natural variability: Sandy soils ~600 mg/kg; Loamy soils ~900 mg/kg; Clayey soils ~1200 mg/kg.

Metric Definition:

Total soil nitrogen content in topsoil (0-15 cm)

Benchmark Definition:

Median total soil nitrogen content in topsoil (0-15 cm) for clayey soils in high-health conservation areas, reflecting natural variability and nutrient status.

Justification:

The benchmark represents the median total nitrogen in topsoil (0-15 cm) for high-health conservation areas. Values are stratified by texture due to natural variability. These values reflect the naturally low nutrient status of the biome. Lower Critical Threshold: < 300 mg/kg, indicating severe degradation and loss of function. Upper Detrimental Threshold: > 2000 mg/kg. Levels above this indicate unnatural enrichment, promoting invasive species and ecosystem degradation. The primary conservation goal is to maintain nitrogen levels within the optimal range (approx. 400–1800 mg/kg) and prevent exceedance of the upper threshold.

Sources (1)

Preview of Soil and Landscape Grid of Australia; Soil nitrogen availability in the cereal zone of South Australia. I. Soil organic carbon, total nitrogen, and nitrogen mineralisation rates

Soil and Landscape Grid of Australia; Soil nitrogen availability in the cereal zone of South Australia. I. Soil organic carbon, total nitrogen, and nitrogen mineralisation rates Government

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

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Effects of nitrogen and phosphorus on vegetation dynamics of a degraded native grassland in semi-arid south-eastern Australia - CSIRO PUBLISHING | The Rangeland Journal, accessed July 13, 2025,

Effects of nitrogen and phosphorus on vegetation dynamics of a degraded native grassland in semi-arid south-eastern Australia - CSIRO PUBLISHING | The Rangeland Journal, accessed July 13, 2025,

Direct Evidence Journal

(PDF) Grassland soil carbon and nitrogen stocks under temperate ..., accessed August 4, 2025,

View Source

SLGA: Soil and Landscape Grid of Australia (Soil Attributes) | Earth Engine Data Catalog

Direct Evidence Journal

Soil and Landscape Grid National Soil Attribute Maps - Total Nitrogen (3" resolution) - Release 2 - CSIRO Data Access Portal, accessed July 13, 2025,

View Source

Soil and Landscape Grid of Australia - CSIRO, accessed July 30, 2025,

Direct Evidence

Soil and Landscape Grid of Australia - CSIRO, accessed August 1, 2025

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

Lower Critical Threshold: 300 mg/kg. Upper Detrimental Threshold: 2000 mg/kg. Maintaining naturally low nitrogen levels is the primary objective. Elevated nitrogen is an indicator of degradation, not health, as it promotes invasive species and disrupts ecosystem function. The optimal range reflects a healthy, stable, and resilient native ecosystem. [Migration] Original wider evidence range: 400 – 1800 (retained OptimalRange: 900 – 1600)

Related Benchmarks

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