Soil Potassium

AUS-TSW-AGR-SOK General Moderate confidence

Benchmark Value

120 mg/kg
Range: 80 to 150 mg/kg
Thresholds: Lower: 40, Upper: 150
Optimal Range: 80 to 150
Direction: Higher is desirable ↑
Form: Point

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 15 benchmarks together — the OptimalRange form drives the primary score, while 14 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard MinimumOnly Guard MaximumOnly Guard MaximumOnly Guard Point Guard Point Guard LowerThreshold Guard OptimalRange Guard Point Guard OptimalRange Guard MinimumOnly Guard OptimalRange Guard LowerThreshold Guard OptimalRange Guard

Evidence & Context

A single point value from within this range is required. A benchmark of 120 mg/kg is proposed as a robust, aspirational, yet achievable target.

Metric Definition:

Colwell K test value representing plant-available potassium in soil for agroecosystem health in temperate semi-arid cropping systems.

Benchmark Definition:

A benchmark value for soil potassium representing the best available condition under sustainable agricultural management in temperate semi-arid cropping systems.

Justification:

This value is functionally optimal, restorative, biologically ambitious, and safe and balanced, supporting ecosystem resilience and counteracting historical potassium rundown.

Sources (3)

Preview of Crop and Pasture Science - CSIRO PUBLISHING, accessed July 10, 2025
Crop and Pasture Science - CSIRO PUBLISHING, accessed July 10, 2025 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 Soil K rundown in the Western grains region – where, why and what ...
Soil K rundown in the Western grains region – where, why and what ... Journal

Soil K rundown in the Western grains region – where, why and what ...

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Preview of Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia - CSIRO PUBLISHING | Crop and Pasture Science
Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia - CSIRO PUBLISHING | Crop and Pasture Science Journal

Review and Synthesis of Potassium Dynamics and Crop Response in Australian Agriculture

View Source

Supporting Sources (13)

Additional references from the underlying research that informed this benchmark.

Preview of 1301.0 - ABS Feature Articles, 1966 - Australian Bureau of Statistics
1301.0 - ABS Feature Articles, 1966 - Australian Bureau of Statistics
Contextual Support Journal

Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia - CSIRO Publishing

View Source
Preview of Comparison of soil analytical methods for estimating plant-available potassium in highly weathered soils - CSIRO Publishing
Comparison of soil analytical methods for estimating plant-available potassium in highly weathered soils - CSIRO Publishing
Contextual Support Journal

Crop and Pasture Science - CSIRO PUBLISHING

View Source
Preview of Long-term rundown of plant-available potassium in Western Australia requires a re-evaluation of potassium management for grain production: a review - BioOne Complete, accessed July 10, 2025
Long-term rundown of plant-available potassium in Western Australia requires a re-evaluation of potassium management for grain production: a review - BioOne Complete, accessed July 10, 2025
Direct Evidence 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 | Crop and Pasture Science, accessed July 24, 2025

View Source
Preview of Long-term rundown of plant-available potassium in Western Australia requires a re-evaluation of potassium management for grain production: a review - CSIRO PUBLISHING | Crop and Pasture Science, accessed July 10, 2025
Long-term rundown of plant-available potassium in Western Australia requires a re-evaluation of potassium management for grain production: a review - CSIRO PUBLISHING | Crop and Pasture Science, accessed July 10, 2025
Contextual Support Journal

Potassium Control of Plant Functions: Ecological and Agricultural Implications - PMC

View Source
Preview of Potassium | Fact Sheets | soilquality.org.au
Potassium | Fact Sheets | soilquality.org.au
Contextual Support Government

Potassium | Fact Sheets | soilquality.org.au

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Preview of Potassium | Nutrient Management - Mosaic Crop Nutrition
Potassium | Nutrient Management - Mosaic Crop Nutrition
Contextual Support Journal

Potassium | Nutrient Management - Mosaic Crop Nutrition

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Preview of Potassium and sulphur - emerging deficiencies in the southern region - GRDC, accessed July 13, 2025
Potassium and sulphur - emerging deficiencies in the southern region - GRDC, accessed July 13, 2025
Contextual Support Government

Potassium and sulphur - emerging deficiencies in the southern region - GRDC

View Source
Preview of Potassium Control of Plant Functions: Ecological and Agricultural Implications - PMC, accessed July 30, 2025,
Potassium Control of Plant Functions: Ecological and Agricultural Implications - PMC, accessed July 30, 2025,
Contextual Support Journal

Regenerative Agriculture - Nuffield Farming Scholarships

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Preview of Potassium for crop production | UMN Extension
Potassium for crop production | UMN Extension
Contextual Support Government

Potassium for crop production | UMN Extension, accessed July 28, 2025,

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Preview of Potassium In Soil Explained - Soil Quality Knowledge Base
Potassium In Soil Explained - Soil Quality Knowledge Base
Contextual Support GreyLiterature

Estimating plant-available potassium in loamy soil - SoilsWest

View Source
Preview of Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed August 5, 2025,
Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed August 5, 2025,
Contextual Support Journal

Regenerative Agriculture—A Literature Review on the Practices and Mechanisms Used to Improve Soil Health - MDPI, accessed August 28, 2025,

View Source
Preview of Soil factors affecting the availability of potassium to plants for Western Australian soils: a glasshouse study | Request PDF - ResearchGate
Soil factors affecting the availability of potassium to plants for Western Australian soils: a glasshouse study | Request PDF - ResearchGate
Direct Evidence Journal

Soil factors affecting the availability of potassium to plants for Western Australian soils: a glasshouse study | Request PDF - ResearchGate

View Source
Preview of Soil nutrient critical limits | MBFP | More Beef from Pastures - MLA, accessed May 13, 2025,
Soil nutrient critical limits | MBFP | More Beef from Pastures - MLA, accessed May 13, 2025,
Contextual Support GreyLiterature

Understanding soil tests for pastures | Soil | Farm management ..., accessed July 17, 2025,

View Source

Context

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

Lifecycle

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

Notes

Lower Critical Threshold: 40 mg/kg. Upper Detrimental Threshold: 150 mg/kg. The benchmark is set well above critical deficiency thresholds to ensure robust ecosystem function, particularly for drought resilience and disease resistance. It sits within an optimal ecological range that avoids upper detrimental thresholds related to nutrient imbalances.