Soil Nitrogen

AUS-TSW-AGR-SON General Moderate confidence

Benchmark Value

No specific value — see range
Thresholds: Lower: 1000, 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 is identified not as a simple value, but as a state of persistent negative nitrogen balance, leading to the degradation of soil capital. This is indicated by TSN levels below approximately 1000 mg/kg for heavier soils and 400 mg/kg for sands.

Metric Definition:

Total Soil Nitrogen (TSN) concentration in the topsoil (0-10 cm)

Benchmark Definition:

Lower critical threshold for Total Soil Nitrogen in loam and clay soils indicating system degradation due to persistent negative nitrogen balance.

Justification:

Indicated by persistent negative nitrogen balance and long-term fertility decline.

Sources (1)

Preview of Opportunities for improving soil carbon and nitrogen stocks in low and medium rainfall cropping systems - GRDC, accessed July 6, 2025,
Opportunities for improving soil carbon and nitrogen stocks in low and medium rainfall cropping systems - GRDC, accessed July 6, 2025, Government

GRDC Soil Health Stocktake (2024)

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of Strategic tillage of a long-term, no-till soil has little impact on soil characteristics or crop growth over five years
Strategic tillage of a long-term, no-till soil has little impact on soil characteristics or crop growth over five years
Contextual Support Journal

Strategic tillage of a long-term, no-till soil has little impact on soil characteristics or crop growth over five years

View Source

Context

  • Region Australia
  • Biome Temperate Semi-Arid Shrublands & Open Woodlands
  • Land Use Agricultural Crop Production
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 20 Mar 2026

Notes

TSN levels below ~1000 mg/kg for loam/clay soils or ~400 mg/kg for sandy soils indicate degradation. No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

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

1500 mg/kg High
Agricultural Crop Production · Pristine Reference
Point Active v1
1000 mg/kg Moderate
Agricultural Crop Production · Pristine Reference
Point Active v1
— mg/kg Moderate
Agricultural Crop Production · Pristine Reference
LowerThreshold Active v1