Soil Nitrogen

AUS-ASC-LVG-SON General High confidence

Benchmark Value

No specific value — see range
Range: 3000 to 1.2E+04 mg/kg
Thresholds: Lower: 3000, Upper: 1.2E+04
Optimal Range: 3000 to 1.2E+04
Direction: Lower 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 13 benchmarks together — the OptimalRange form drives the primary score, while 12 guard(s) constrain the result.

Evidence & Context

The Kirkpatrick et al. (2014) study found that Total Nitrogen in the top 5 cm of Australian alpine soils ranged from 0.3% to 1.2%.14 This is equivalent to a range of 3,000 to 12,000 mg/kg.

Metric Definition:

Total Nitrogen content in the top 5 cm of soil in Australian alpine soils.

Benchmark Definition:

Total Nitrogen content in the top 5 cm of soil in Australian alpine soils represents the natural variation in healthy, high-organic matter Alpine Humus Soils, with higher values indicating greater accumulation of stable organic matter.

Justification:

This range for Total Nitrogen (0.3–1.2%) is from the most comprehensive survey of Australian alpine soils (Kirkpatrick et al., 2014, n=219), representing the natural variation in healthy, high-organic matter Alpine Humus Soils. In this N-conservative system, higher values within this range indicate greater accumulation of stable organic matter, representing the best available ecological condition.

Sources (1)

Preview of Patterns of variation in Australian alpine soils and their relationships to parent material, vegetation formation, climate and topography | Request PDF - ResearchGate, accessed August 3, 2025,
Patterns of variation in Australian alpine soils and their relationships to parent material, vegetation formation, climate and topography | Request PDF - ResearchGate, accessed August 3, 2025, Journal

Patterns of variation in Australian alpine soils and their relationships to parent material, vegetation formation, climate and topography | Request PDF - ResearchGate

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Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Australian dryland soils are acidic and nutrient‐depleted, and have unique microbial communities compared with other drylands - Arid Ecology Lab, accessed August 3, 2025
Australian dryland soils are acidic and nutrient‐depleted, and have unique microbial communities compared with other drylands - Arid Ecology Lab, accessed August 3, 2025
Direct Evidence Government

Beringer, J., et al. 2022. Carbon and water fluxes over a temperate Eucalyptus forest and a tropical wet/dry savanna in Australia. Agricultural and Forest Meteorology 129(3):151-173.

View Source
Preview of Impact of atmospheric Nitrogen deposition on upland and alpine ecosystems
Impact of atmospheric Nitrogen deposition on upland and alpine ecosystems
Contextual Support Journal

Impact of atmospheric Nitrogen deposition on upland and alpine ecosystems

View Source
Preview of STATEMENTS OF UNACCEPTABILITY OF GRAZING IN THE AUSTRALIAN ALPS
STATEMENTS OF UNACCEPTABILITY OF GRAZING IN THE AUSTRALIAN ALPS
Contextual Support

STATEMENTS OF UNACCEPTABILITY OF GRAZING IN THE AUSTRALIAN ALPS

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Context

  • Region Australia
  • Biome Alpine and Subalpine Complex
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 24 Mar 2026

Notes

Livestock grazing is considered incompatible with maintaining the values of this biome; therefore, an ungrazed reference condition is used. The system is highly sensitive to N enrichment. Total N values significantly above the natural range (>12,000 mg/kg) would indicate an unnatural, eutrophic state. Even small inputs of available N can cause loss of biodiversity and soil acidification.