Soil Nitrogen

AUS-TDG-CON-SON General Moderate confidence

Benchmark Value

2500 mg/kg

Direction: Higher is desirable ↑

Form: MaximumOnly

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 4 benchmarks together — the OptimalRange form drives the primary score, while 3 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard MinimumOnly Guard MaximumOnly Guard

Evidence & Context

Total nitrogen values persistently exceeding approximately 2000-2500 mg/kg, or any evidence of chronically high nitrate availability, should trigger investigations into potential sources of nutrient enrichment.

Metric Definition:

Upper detrimental threshold for total soil nitrogen concentration in the 0-10 cm topsoil layer above which ecological imbalance or degradation occurs

Benchmark Definition:

This benchmark defines the upper detrimental threshold of total soil nitrogen concentration in the 0-10 cm topsoil layer above which ecosystem degradation is likely in temperate dry woodlands and native grasslands under conservation management.

Justification:

This threshold is based on evidence that sustained total nitrogen levels significantly above 2000-2500 mg/kg, especially with high nitrate availability, lead to detrimental ecological conditions favoring invasive species.

Sources (1)

Preview of Prober, S. M., Lunt, I. D., & Thiele, K. R. (2002). Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany, 50(6), 687–697.

Prober, S. M., Lunt, I. D., & Thiele, K. R. (2002). Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany, 50(6), 687–697. Journal

Prober, S.M., Thiele, K.R. and Lunt, I.D. (2002). Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany, 50(6), 687-697.

View Source

Supporting Sources (10)

Additional references from the underlying research that informed this benchmark.

Preview of Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants - CSIRO PUBLISHING | Australian Journal of Botany, accessed August 12, 2025,

Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants - CSIRO PUBLISHING | Australian Journal of Botany, accessed August 12, 2025,

Direct Evidence Journal

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

View Source

Preview of Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Contextual Support GreyLiterature

(PDF) Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 4, 2025,

View Source

Impacts of Land Use on Soil Nitrogen-Cycling Microbial Communities - PubMed Central, accessed May 19, 2025,

Contextual Support Journal

Impacts of Land Use on Soil Nitrogen-Cycling Microbial Communities - PubMed Central

View Source

Preview of Investigating the Zonal Response of Spatiotemporal Dynamics of Australian Grasslands to Ongoing Climate Change - MDPI, accessed May 19, 2025,

Investigating the Zonal Response of Spatiotemporal Dynamics of Australian Grasslands to Ongoing Climate Change - MDPI, accessed May 19, 2025,

Contextual Support Journal

Investigating the Zonal Response of Spatiotemporal Dynamics of Australian Grasslands to Ongoing Climate Change - MDPI

View Source

openresearch-repository.anu.edu.au, accessed May 19, 2025,

Contextual Support Journal

openresearch-repository.anu.edu.au

View Source

Preview of Prober, S. M., & Thiele, K. R. (2005). Ecological and anthropomorphic factors permitting low-risk assisted colonization in temperate grassy woodlands.

Prober, S. M., & Thiele, K. R. (2005). Ecological and anthropomorphic factors permitting low-risk assisted colonization in temperate grassy woodlands.

Direct Evidence Journal

(PDF) Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants - ResearchGate, accessed May 19, 2025,

View Source

Restoring Australia's temperate grasslands and grassy woodlands | Request PDF - ResearchGate, accessed August 12, 2025,

Contextual Support

Restoring Australia's temperate grasslands and grassy woodlands | Request PDF - ResearchGate

View Source

Preview of Restoring ecological function in temperate grassy woodlands: Manipulating soil nutrients, exotic annuals and native perennial grasses through carbon supplements and spring burns | Request PDF - ResearchGate, accessed May 12, 2025

Restoring ecological function in temperate grassy woodlands: Manipulating soil nutrients, exotic annuals and native perennial grasses through carbon supplements and spring burns | Request PDF - ResearchGate, accessed May 12, 2025

Contextual Support GreyLiterature

Increasing and declining native species in urban remnant grasslands respond differently to nitrogen addition and disturbance

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,

Contextual Support Government

Geology | Norfolk Island National Park | Parks Australia

View Source

www.environment.vic.gov.au, accessed May 19, 2025,

Contextual Support Journal

www.environment.vic.gov.au

View Source

Context

Region Australia
Biome Temperate Dry Woodlands & Native Grasslands
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 9 Jun 2026

Notes

Sustained total N significantly above 2000 mg/kg, or conditions leading to high N availability (e.g., high nitrate), can be detrimental, favoring invasive species and reducing native biodiversity.

Related Benchmarks

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