Soil Nitrogen

AUS-ASP-AGR-SON General High confidence

Benchmark Value

1450 mg/kg
Thresholds: Lower: 1450, Upper: —
Direction: Higher is desirable ↑
Form: LowerThreshold

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context.

Evidence & Context

A lower critical threshold for topsoil (0–10 cm) is identified at approximately 1450 mg/kg, below which the soil's capacity to accumulate and stabilize organic carbon is significantly constrained.

Metric Definition:

Lower critical threshold of total soil nitrogen in the top 10 cm below which ecosystem function is impaired.

Benchmark Definition:

Critical lower threshold of total soil nitrogen indicating functional impairment of soil carbon sequestration.

Justification:

Identified by a landmark study using interpretable machine learning showing constraint on soil organic carbon accumulation below this threshold.

Sources (1)

Preview of A review of sampling designs for the measurement of soil organic carbon in Australian grazing lands - Integrity Systems, accessed July 27, 2025,
A review of sampling designs for the measurement of soil organic carbon in Australian grazing lands - Integrity Systems, accessed July 27, 2025, Government

Total nitrogen levels as a key constraint on soil organic carbon ...

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Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Preview of Regenerative opportunities for building soil biological resilience – a ..., accessed May 11, 2025
Regenerative opportunities for building soil biological resilience – a ..., accessed May 11, 2025
Direct Evidence GreyLiterature

Soil and fertilizer phosphorus: Effects on plant P supply and mycorrhizal development - Canadian Science Publishing, accessed August 28, 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,
Contextual Support Government

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

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Context

  • Region Australia
  • Biome Arid Shrublands & Stony Plains
  • Land Use Agricultural Crop Production
  • Assessment Conservation Target
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

This threshold falls within the upper end of the observed benchmark range for sandy soils, indicating many managed sandy soils may be near this limit.