Soil Nitrogen

AUS-TSR-AGR-SON General Moderate confidence

Benchmark Value

No specific value — see range
Range: 1500 to 2500 mg/kg
Thresholds: Lower: 500, Upper: —
Optimal Range: 1500 to 2500
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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard Point Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard OptimalRange Guard Point Guard LowerThreshold Guard OptimalRange Guard

Evidence & Context

The benchmark represents the total nitrogen (TN) range for high-health loamy to clayey soils under best-practice regenerative agriculture.

Metric Definition:

Total nitrogen concentration in soil representing a functionally healthy state under best-practice regenerative agriculture in tropical and subtropical rainforest agricultural soils.

Benchmark Definition:

This benchmark defines the total nitrogen range in soil that indicates a healthy state for loamy to clayey soils under best-practice regenerative agriculture in tropical and subtropical rainforest agricultural areas.

Justification:

It is derived by triangulating two lines of evidence: 1) TN values calculated from the widely accepted 2-2.5% soil organic carbon (SOC) threshold for maintaining soil quality in the tropics, and 2) the functional state required to support the 'High' Soil Nitrogen Supply (50-125 mg/kg) identified as optimal for these soil types by Soil Quality Australia.

Sources (3)

Preview of Influence of environmental conditions and some soil chemical properties on the carbon and nitrogen contents of some tropical Australian rainforest soils - CSIRO PUBLISHING | Soil Research, accessed August 2, 2025
Influence of environmental conditions and some soil chemical properties on the carbon and nitrogen contents of some tropical Australian rainforest soils - CSIRO PUBLISHING | Soil Research, accessed August 2, 2025 Journal

Influence of environmental conditions and some soil chemical properties on the carbon and nitrogen contents of some tropical Australian rainforest soils - ResearchGate, accessed August 2, 2025

View Source
Preview of Soil Nitrogen Supply | Fact Sheets | soilquality.org.au, accessed July 25, 2025,
Soil Nitrogen Supply | Fact Sheets | soilquality.org.au, accessed July 25, 2025, Government

Soil Nitrogen Supply | Fact Sheets | soilquality.org.au, accessed May 11, 2025,

View Source
Preview of Sub tropical banana nutrition - Hort Innovation
Sub tropical banana nutrition - Hort Innovation

Sub tropical banana nutrition - Hort Innovation, accessed July 16, 2025,

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Rainforests
  • Land Use Agricultural Crop Production
  • Assessment Pristine Reference
  • Evidence Type TargetCondition

Lifecycle

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

Notes

For sandier soils with lower carbon-holding capacity, a lower range of 1000-1500 mg/kg is more appropriate. Lower Critical Threshold: Evidence suggests a threshold near 500 mg/kg TN (corresponding to <0.5% SOC), below which soil ecosystem functions like nutrient cycling are severely compromised, and crop response to inputs is poor. Upper Detrimental Threshold: There is strong evidence for an upper limit where excess nitrogen becomes detrimental, causing reduced crop quality (e.g., in avocados and bananas) and significant environmental harm via leaching and greenhouse gas emissions.