Soil Potassium

AUS-TDG-AGR-SOK General Moderate confidence

Benchmark Value

No specific value — see range
Range: 150 to 250 mg/kg
Optimal Range: 150 to 250
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.

Evidence & Context

A synthesized value of 150–250 mg/kg (Colwell K) is proposed for loamy soils, with adjustments necessary based on soil texture (e.g., 120–200 mg/kg for sandy loams).

Metric Definition:

Soil potassium concentration measured as Colwell K in the 0-10 cm soil depth.

Benchmark Definition:

Soil potassium benchmark representing high environmental health for sustainable agricultural crop production.

Justification:

This range is positioned towards the upper end of what is considered "Ideal" or "Adequate" for productive agricultural systems on loamy soils and overlaps with the lower to mid-range of available K found in open, grassy areas of little-grazed native temperate woodlands.

Sources (3)

Preview of Potassium | Fact Sheets | soilquality.org.au, accessed August 11, 2025,
Potassium | Fact Sheets | soilquality.org.au, accessed August 11, 2025, Government

Potassium | Fact Sheets | soilquality.org.au

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Preview of Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025
Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025 Government

Agriculture Victoria. (2025). Understanding soil tests for pastures. Farm Management.

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Preview of What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed August 5, 2025,
What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed August 5, 2025, Government

What are the optimum nutrient targets for pastures? - Soil Health Knowledgebase, accessed July 18, 2025

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Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Preview of Crop and Pasture Science - CSIRO PUBLISHING, accessed July 10, 2025
Crop and Pasture Science - CSIRO PUBLISHING, accessed July 10, 2025
Contextual Support Journal

Long-term rundown of plant-available potassium in Western Australia requires a re-evaluation of potassium management for grain production: a review - CSIRO Publishing, accessed July 17, 2025

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Preview of Regenerative agriculture – Case studies from Western Australia, accessed May 13, 2025
Regenerative agriculture – Case studies from Western Australia, accessed May 13, 2025
Contextual Support

Soil management guides - NSW Department of Primary Industries

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Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Agricultural Crop Production
  • Assessment Conservation Target
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 8 Jun 2026

Notes

The range should be adjusted based on soil texture, generally targeting the upper end of "Ideal" or "Adequate" ranges provided by state agricultural guidelines. It reflects a state achievable under best-practice sustainable or regenerative management focused on long-term soil health.

Related Benchmarks

Other benchmarks in the AUS-TDG-AGR-SOK family.

— mg/kg Moderate
Agricultural Crop Production · Conservation Target
OptimalRange Active v1