Soil Potassium

AUS-TDG-LVG-SOK General Moderate confidence

Benchmark Value

No specific value — see range
Direction: Higher is desirable ↑
Form: CompositeFramework

Scoring Curve

Scoring curve unavailable

The scoring engine could not generate a curve for this benchmark context. The primary form is CompositeFramework, but the benchmark data may be missing required fields (e.g., optimal range bounds for an OptimalRange benchmark). This is typically a data quality issue in the benchmark pipeline.

Evidence & Context

Potential Upper Limit or Detrimental Threshold (Colwell K, mg/kg and/or Cation Ratios): Exchangeable potassium consistently > 8-10% of the soil's Cation Exchange Capacity (CEC). A Magnesium to Potassium (Mg:K) ratio < 1.5:1 in herbage, indicative of soil imbalances. Sustained Colwell K levels falling into the "High" agronomic ranges (e.g., for Sandy Loams: >170-200 mg/kg; for Clay Loams: >250-300 mg/kg) should trigger investigation for potential nutrient imbalances, unnatural enrichment, or negative shifts in native species diversity.

Metric Definition:

Indicators of potential upper detrimental thresholds for soil potassium including Colwell K concentration, exchangeable potassium percentage of CEC, and herbage Mg:K ratio.

Benchmark Definition:

Upper detrimental threshold indicators for soil potassium based on multiple metrics.

Justification:

Based on documented risks of nutrient imbalances and animal health issues linked to high soil potassium levels.

Sources (3)

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

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

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

Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - CSIRO Publishing, accessed July 17, 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 Government

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

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

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

Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Livestock Grazing & Pasture
  • Assessment Not Stated
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 10 Jun 2026

Notes

Includes Colwell K sustained high levels, exchangeable K >8-10% of CEC, and herbage Mg:K ratio <1.5:1 as indicators for investigation. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.