Soil Nitrogen

AUS-TMS-AGR-SON General Moderate confidence

Benchmark Value

No specific value — see range

Range: 700 to 1200 mg/kg

Optimal Range: 700 to 1200

Direction: Higher 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 7 benchmarks together — the OptimalRange form drives the primary score, while 6 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard MinimumOnly Guard Point Guard MinimumOnly Guard MinimumOnly Guard OptimalRange Guard

Evidence & Context

An indicative optimal range is suggested as 700 to 1200 mg/kg total N (topsoil). This range aims to balance the inherent low fertility of savanna soils with achievable levels under effective regenerative management, promoting both productivity and ecological health.

Metric Definition:

Optimal functional range of total soil nitrogen concentration in topsoil supporting ecological health and sustainable agricultural production.

Benchmark Definition:

This benchmark represents the optimal range of total soil nitrogen concentration in topsoil for balancing productivity and ecological health in Tropical Monsoonal Savannas under agricultural crop production.

Justification:

Inferred from observed values in well-managed legume-based systems and literature on sustainable nitrogen levels in tropical savanna soils.

Sources (1)

Soil organic carbon and total nitrogen under Leucaena leucocephala pastures in Queensland - ResearchGate Journal

Soil organic carbon and total nitrogen under Leucaena leucocephala pastures in Queensland

View Source

Supporting Sources (5)

Additional references from the underlying research that informed this benchmark.

Preview of Comparison of legume-based cropping systems at Warra, Queensland. I. Soil nitrogen and organic carbon accretion and potentially mineralisable nitrogen.

Comparison of legume-based cropping systems at Warra, Queensland. I. Soil nitrogen and organic carbon accretion and potentially mineralisable nitrogen.

Direct Evidence

Comparison of legume-based cropping systems at Warra, Queensland. I. Soil nitrogen and organic carbon accretion and potentially mineralisable nitrogen.

View Source

$Preview of Mapping soil organic carbon fractions for Australia, their stocks, and uncertainty - BG, accessed August 5, 2025,$

Mapping soil organic carbon fractions for Australia, their stocks, and uncertainty - BG, accessed August 5, 2025,

Contextual Support Journal

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

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

Soil Nitrogen Supply | Fact Sheets | soilquality.org.au, accessed July 25, 2025,

Contextual Support Government

Nitrogen Fixation in Acacias - AgEcon Search, accessed July 30, 2025,

View Source

Soil organic carbon and total nitrogen under Leucaena ..., accessed May 11, 2025,

Contextual Support Journal

Soil organic carbon and total nitrogen under Leucaena ..., accessed May 11, 2025,

View Source

Context

Region Australia
Biome Tropical Monsoonal Savannas
Land Use Agricultural Crop Production
Assessment Not Stated
Evidence Type HealthyOperationalRange

Lifecycle

Status Active
Version 1
Effective From 10 Jun 2026

Notes

Range is indicative and varies with soil type, management practices, and local conditions. No upper detrimental threshold — higher values are always better up to natural saturation. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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