Soil Nitrogen

AUS-AKW-CON-SON General Moderate confidence

Benchmark Value

450 mg/kg
Range: 300 to 600 mg/kg
Optimal Range: 300 to 600
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. 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 OptimalRange Guard Point Guard

Evidence & Context

The analysis of the SLGA Total Nitrogen data for the 0-15 cm topsoil layer across the Nullarbor National Park and Wilderness Protection Area yielded a median value of 450 mg/kg.

Metric Definition:

Total soil nitrogen concentration in the topsoil (0-15 cm) layer.

Benchmark Definition:

Median total nitrogen concentration for the topsoil (0-15 cm) within the Nullarbor National Park and Wilderness Protection Area, representing the best-managed examples of the Arid Karstic Woodlands & Shrublands biome.

Justification:

Confidence is 'Moderate' as the value is from a high-quality national model, not direct field sampling across the entire reference area.

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 (26)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate, accessed July 13, 2025
(PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate, accessed July 13, 2025
Contextual Support

(PDF) Mineral Nutrition of Plants in Australia's Arid Zone - ResearchGate

View Source
Preview of (PDF) Nitrogen rather than water availability limits aboveground ..., accessed July 26, 2025,
(PDF) Nitrogen rather than water availability limits aboveground ..., accessed July 26, 2025,
Contextual Support

Global assessment of nitrogen deposition effects on terrestrial plant diversity : a synthesis - Marshall Digital Scholar, accessed July 26, 2025,

View Source
Preview of (PDF) Soil and Landscape Grid of Australia - ResearchGate
(PDF) Soil and Landscape Grid of Australia - ResearchGate
Direct Evidence

SLGA: Soil and Landscape Grid of Australia (Soil Attributes) | Earth Engine Data Catalog, accessed July 26, 2025,

View Source
Preview of An inventory and condition survey of the Western Australian part of the Nullarbor region - DPIRD's Digital library, accessed July 25, 2025
An inventory and condition survey of the Western Australian part of the Nullarbor region - DPIRD's Digital library, accessed July 25, 2025
Contextual Support Government

An inventory and condition survey of the Western Australian part of the Nullarbor region - DPIRD's Digital library, accessed July 26, 2025,

View Source
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
Contextual Support 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 Bulk Density - Measurement | Fact Sheets | soilquality.org.au, accessed August 9, 2025,
Bulk Density - Measurement | Fact Sheets | soilquality.org.au, accessed August 9, 2025,
Contextual Support Government

Bulk Density - Measurement | Fact Sheets | soilquality.org.au, accessed July 26, 2025,

View Source
Preview of Categories - total soil nitrogen - CSIRO Data Access Portal, accessed July 26, 2025,
Categories - total soil nitrogen - CSIRO Data Access Portal, accessed July 26, 2025,
Contextual Support Government

NEW! TERN-ANU Landscape Data Visualiser | TERN Australia, accessed July 26, 2025,

View Source
Preview of Chapter 9 AUSTRALIAN GRASSLANDS - Food and Agriculture Organization of the United Nations, accessed August 5, 2025,
Chapter 9 AUSTRALIAN GRASSLANDS - Food and Agriculture Organization of the United Nations, accessed August 5, 2025,
Contextual Support Government

Karst and agriculture in Australia - Digital Commons @ USF, accessed July 26, 2025,

View Source
Preview of Different nitrogen saturation thresholds for above-, below-, and total ..., accessed July 26, 2025,
Different nitrogen saturation thresholds for above-, below-, and total ..., accessed July 26, 2025,
Contextual Support

Different nitrogen saturation thresholds for above-, below-, and total ..., accessed July 26, 2025,

View Source
Preview of Geography of Western Australia - Wikipedia, accessed July 26, 2025,
Geography of Western Australia - Wikipedia, accessed July 26, 2025,
Contextual Support GreyLiterature

Geography of Western Australia - Wikipedia, accessed July 26, 2025,

View Source
Preview of High clay contents, dense soils, and spatial variability are the principal subsoil constraints to cropping the higher rainfall land in south-eastern Australia - CSIRO Publishing, accessed July 7, 2025
High clay contents, dense soils, and spatial variability are the principal subsoil constraints to cropping the higher rainfall land in south-eastern Australia - CSIRO Publishing, accessed July 7, 2025
Contextual Support Journal

High clay contents, dense soils, and spatial variability are the principal subsoil constraints to cropping the higher rainfall land in south-eastern Australia - CSIRO Publishing, accessed July 26, 2025,

View Source
Preview of Karst wetlands - WetlandInfo, accessed July 26, 2025,
Karst wetlands - WetlandInfo, accessed July 26, 2025,
Contextual Support Journal

Karst wetlands - WetlandInfo, accessed July 26, 2025,

View Source
Preview of Management Plan - Department for Environment and Water, accessed July 26, 2025,
Management Plan - Department for Environment and Water, accessed July 26, 2025,
Contextual Support Government

Regional reserves - Department for Environment and Water, accessed July 26, 2025,

View Source
Preview of Nullarbor - DBCA Library
Nullarbor - DBCA Library
Contextual Support Journal

Karst features and remnant dune systems on the Nullarbor Plain, Australia, accessed July 26, 2025,

View Source
Preview of Nullarbor - Department for Environment and Water, accessed July 26, 2025,
Nullarbor - Department for Environment and Water, accessed July 26, 2025,
Contextual Support Journal

Wilderness protection in South Australia - Department for Environment and Water, accessed July 26, 2025,

View Source
Preview of Nullarbor - Department for Environment and Water, accessed July 27, 2025
Nullarbor - Department for Environment and Water, accessed July 27, 2025
Contextual Support Journal

Conservation areas - Department for Energy and Mining, accessed July 26, 2025,

View Source
Preview of Nullarbor bioregion - DCCEEW, accessed July 26, 2025,
Nullarbor bioregion - DCCEEW, accessed July 26, 2025,
Contextual Support

Interim Biogeographic Regionalisation for Australia (IBRA) Version 6.1 (Regions) | Find Environmental Data, accessed July 26, 2025,

View Source
Preview of Nullarbor National Park, Wilderness Protection Area and Regional Reserve, accessed July 27, 2025
Nullarbor National Park, Wilderness Protection Area and Regional Reserve, accessed July 27, 2025
Contextual Support Government

Nullarbor Parks - Department for Environment and Water, accessed July 26, 2025,

View Source
Preview of Nullarbor Plain - Wikipedia, accessed July 25, 2025,
Nullarbor Plain - Wikipedia, accessed July 25, 2025,
Contextual Support GreyLiterature

Nullarbor Plain - Wikipedia, accessed July 24, 2025

View Source
Preview of NVIS Fact sheet MVG 22 – Chenopod shrublands, samphire shrublands and forblands - DCCEEW, accessed July 24, 2025
NVIS Fact sheet MVG 22 – Chenopod shrublands, samphire shrublands and forblands - DCCEEW, accessed July 24, 2025
Contextual Support Journal

Some Characteristics of Calcareous soils. A review A.S. Taalab1, G.W. Ageeb2, Hanan S. Siam1 and Safaa A. Mahmoud1 - CURRENT RESEARCH WEB, accessed July 26, 2025,

View Source
Preview of Resource condition, accessed July 26, 2025,
Resource condition, accessed July 26, 2025,
Contextual Support GreyLiterature

Australian Soils and Landscapes: An Illustrated Compendium - ResearchGate, accessed July 26, 2025,

View Source
Preview of Resource condition, accessed July 27, 2025
Resource condition, accessed July 27, 2025
Contextual Support Journal

Long-term nitrogen deposition enhances microbial capacities in soil carbon stabilization but reduces network complexity - PubMed Central, accessed July 26, 2025,

View Source
Preview of Soil and Landscape Grid National Soil Attribute Maps - Total Nitrogen (3" resolution) - Release 2 - CSIRO Data Access Portal, accessed August 5, 2025,
Soil and Landscape Grid National Soil Attribute Maps - Total Nitrogen (3" resolution) - Release 2 - CSIRO Data Access Portal, accessed August 5, 2025,
Direct Evidence Government

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

View Source
Preview of Soil and Landscape Grid of Australia - esoil.io, accessed July 13, 2025
Soil and Landscape Grid of Australia - esoil.io, accessed July 13, 2025
Direct Evidence Government

Soil and Landscape Grid of Australia - esoil.io, accessed July 26, 2025,

View Source
Preview of Soil organic matter in cropping systems - NSW Department of Primary Industries, accessed July 22, 2025,
Soil organic matter in cropping systems - NSW Department of Primary Industries, accessed July 22, 2025,
Contextual Support Journal

III. WORKING PAPERS - Food and Agriculture Organization of the United Nations, accessed July 26, 2025,

View Source
Preview of Summary of Major Soil Features1 - Enviro Data SA, accessed July 26, 2025,
Summary of Major Soil Features1 - Enviro Data SA, accessed July 26, 2025,
Contextual Support Journal

1301.0 - ABS Feature Articles, 1966 - Australian Bureau of Statistics, accessed July 26, 2025,

View Source

Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 25 Mar 2026

Notes

Lower Critical Threshold is a functional threshold defined by loss of perennial chenopod shrub cover and soil surface exposure leading to erosion. Optimal range is approximately 300–600 mg/kg supporting resilient native plant community. Upper Detrimental Threshold is above 600 mg/kg indicating degradation due to external nitrogen inputs causing biodiversity loss and soil acidification. Higher nitrogen is not better; conformity to the naturally low benchmark is optimal.