Soil Nitrogen

AUS-TMS-FOR-SON General Moderate confidence

Benchmark Value

No specific value — see range

Range: 400 to 500 mg/kg

Thresholds: Lower: 400, Upper: —

Optimal Range: 400 to 500

Direction: Higher is desirable ↑

Form: OptimalRange

Scoring Curve

Scoring curve unavailable

The scoring engine could not generate a curve for this benchmark context. The primary form is CompositeFramework, but the benchmark data may be missing required fields (e.g., optimal range bounds for an OptimalRange benchmark). This is typically a data quality issue in the benchmark pipeline.

Contributing Benchmarks

CompositeFramework Primary OptimalRange Guard LowerThreshold Guard UpperThreshold Guard Point Guard MinimumOnly Guard OptimalRange Guard MaximumOnly Guard Point Guard OptimalRange Guard Point Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard Point Guard OptimalRange Guard MaximumOnly Guard Point Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard OptimalRange Guard

Evidence & Context

Lower Critical Threshold: Approximately 400-500 mg/kg. Below this, severe N deficiency and impaired ecosystem functions are likely.

Metric Definition:

Lower critical threshold of total soil nitrogen concentration in the topsoil below which ecosystem functions and sustainability are impaired.

Benchmark Definition:

Lower critical threshold of total soil nitrogen concentration in the topsoil below which ecosystem functions and sustainability are impaired.

Justification:

Based on the lowest reported values in functioning, albeit N-poor, savanna systems, representing conditions approaching or at a lower functional bound.

Sources (1)

Preview of Butterbach-Bahl, K., Kiese, R., Liu, C., & Werner, C. (2014). Nitrogen and greenhouse gas dynamics in managed and natural savanna and pasture ecosystems in northern Australia. Biogeosciences, 11(21), 6047-6062.

Butterbach-Bahl, K., Kiese, R., Liu, C., & Werner, C. (2014). Nitrogen and greenhouse gas dynamics in managed and natural savanna and pasture ecosystems in northern Australia. Biogeosciences, 11(21), 6047-6062. Journal

N$_2$O, NO, N$_2$ and CO$_2$ emissions from tropical savanna and grassland of northern Australia: an incubation experiment with intact soil cores

View Source

Supporting Sources (11)

Additional references from the underlying research that informed this benchmark.

Australia's tropical savannas: vast, ancient and rich landscapes - CSIRO Research Publications Repository, accessed May 11, 2025,

Contextual Support GreyLiterature

NDVI vs NDMI: Understanding Key Vegetation Indices for Precision Agriculture -

View Source

Preview of Does rapid utilization of elevated nutrient availability allow eucalypts to dominate in the tropical savannas of Australia? - PubMed Central

Does rapid utilization of elevated nutrient availability allow eucalypts to dominate in the tropical savannas of Australia? - PubMed Central

Contextual Support Journal

Does rapid utilization of elevated nutrient availability allow eucalypts to dominate in the tropical savannas of Australia? - PubMed Central

View Source

Effect of fire and tree‐grass patches on soil nitrogen in Australian tropical savannas

Contextual Support Journal

Size-specific biomass allocation and water content of above- and below-ground components of three Eucalyptus species in a northern Australian savanna - ResearchGate

View Source

Landscape Monitoring for Landscape Research | Landscape ..., accessed July 22, 2025,

Contextual Support

TERN Landscapes - Terrestrial Ecosystem Research Network, accessed May 15, 2025

View Source

Preview of Plantation tree growth responses to P, N, K and minor and trace elements on low fertility savanna soils - ResearchGate, accessed May 16, 2025,

Plantation tree growth responses to P, N, K and minor and trace elements on low fertility savanna soils - ResearchGate, accessed May 16, 2025,

Contextual Support Journal

Agnote - Northern Territory Government

View Source

Recent insights in soil nutrient cycling: perspectives from Pinus and Eucalyptus forest studies around the world

Contextual Support Journal

Nitrogen cycling in tree plantations grown on a poor sandy savanna soil in Congo - Horizon IRD

View Source

Review of C:N Ratios in Vegetation, Litter and Soil Under Australian Native Forests and Plantations - DCCEEW

Contextual Support Journal

Review of C:N Ratios in Vegetation, Litter and Soil ... - DCCEEW

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, accessed August 2, 2025

View Source

Preview of Soil management for sustainable agriculture : background papers from a workshop organized by the Research Review Committee of th, accessed July 7, 2025

Soil management for sustainable agriculture : background papers from a workshop organized by the Research Review Committee of th, accessed July 7, 2025

Contextual Support Government

Soil management guides - NSW Department of Primary Industries

View Source

Soil Research - CSIRO PUBLISHING, accessed May 16, 2025,

Contextual Support Journal

Litchfield Savanna BASE Contextual, Soil Physico-Chemical Data ...

View Source

Wildfire effects on soils and soil processes - CSIRO Publishing, accessed July 24, 2025,

Contextual Support GreyLiterature

Fire regime impacts on soil microbes, soil organic carbon and ground cover in an Australian tropical savanna - CSIRO Publishing

View Source

Context

Region Australia
Biome Tropical Monsoonal Savannas
Land Use Production Forestry
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Superseded
Version 1
Effective From 24 Mar 2026
Effective To 24 Mar 2026

Notes

Below this threshold, severe N deficiency symptoms in trees, poor regeneration, reduced growth rates, and breakdown in nutrient cycling processes are anticipated.

Related Benchmarks

Other benchmarks in the AUS-TMS-FOR-SON family.