Soil Potassium

AUS-TDG-LVG-SOK General Moderate confidence

Benchmark Value

200 mg/kg
Thresholds: Lower: —, Upper: 200
Direction: Higher is desirable ↑
Form: UpperThreshold

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 3 benchmarks together — the OptimalRange form drives the primary score, while 2 guard(s) constrain the result.

Evidence & Context

Sustained Colwell K levels falling into the "High" agronomic ranges (e.g., for Sandy Loams: >170-200 mg/kg) should trigger investigation for potential nutrient imbalances.

Metric Definition:

Colwell K soil potassium concentration in mg/kg

Benchmark Definition:

This benchmark represents the upper detrimental threshold of soil potassium concentration above which nutrient imbalances and ecosystem harm may occur in sandy loam soils under grazing in temperate dry woodlands and native grasslands in Australia.

Justification:

High potassium levels can induce magnesium and calcium deficiencies, leading to animal health issues and ecosystem imbalance.

Sources (1)

Preview of Lowland Native Grassland Ecosystem Condition Monitoring Plan
Lowland Native Grassland Ecosystem Condition Monitoring Plan

Understanding soil tests for pastures | Soil | Farm management ...

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Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Potassium | Fact Sheets | soilquality.org.au, accessed July 10, 2025
Potassium | Fact Sheets | soilquality.org.au, accessed July 10, 2025
Contextual Support Government

Potassium - Tas | Fact Sheets | soilquality.org.au, accessed May 11, 2025,

View Source
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
Direct Evidence Government

Understanding soil tests for pastures

View Source
Preview of www.act.gov.au, accessed May 11, 2025,
www.act.gov.au, accessed May 11, 2025,
Contextual Support Journal

www.act.gov.au, accessed May 11, 2025,

View Source