Soil Nitrogen

AUS-ASP-AGR-SON General Moderate confidence

Benchmark Value

1450 mg/kg
Direction: Higher is desirable ↑
Form: MinimumOnly

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.

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:

This benchmark defines the minimum total soil nitrogen level in topsoil below which soil organic carbon accumulation and ecosystem function are impaired.

Justification:

Based on a landmark study identifying depth-specific TN thresholds that constrain soil carbon accumulation.

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 ...

View Source

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

Regenerative opportunities for building soil biological resilience – a case study in the low-rainfall zone in Southern Australia - GRDC

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

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

View Source

Context

  • Region Australia
  • Biome Arid Shrublands & Stony Plains
  • Land Use Agricultural Crop Production
  • Assessment Not Stated
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 9 Jun 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. This threshold indicates functional impairment and ecosystem degradation when total nitrogen falls below this level. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.