Soil Potassium

AUS-AIF-FOR-SOK General Moderate confidence

Benchmark Value

500 mg/kg
Direction: Higher is desirable ↑
Form: Point

Scoring Curve

Scoring curve unavailable

The scoring engine could not generate a curve for this benchmark context. The primary form is Point, 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

A reference value of 500 mg/kg of available potassium is proposed.

Metric Definition:

Available soil potassium concentration in topsoil (0-10 cm) measured as exchangeable potassium or equivalent method.

Benchmark Definition:

This benchmark represents the concentration of available potassium in soil that supports a healthy, resilient native forest ecosystem under sustainable production forestry in the arid inland floodplains biome.

Justification:

Derived from Goulburn Broken CMA target of 3-8% of CEC for clay soils, assuming an average CEC of 30 cmol(+)/kg. Lower threshold informed by Eucalyptus research and NSW pasture data.

Sources (3)

Preview of NSW Department of Primary Industries
NSW Department of Primary Industries GreyLiterature

NSW Department of Primary Industries guidelines for pasture legumes on clay loam soils

View Source
Preview of Potassium limitation of forest productivity – Part 1: A mechanistic model simulating the effects of potassium availability on canopy carbon and water fluxes in tropical eucalypt stands - BG
Potassium limitation of forest productivity – Part 1: A mechanistic model simulating the effects of potassium availability on canopy carbon and water fluxes in tropical eucalypt stands - BG GreyLiterature

Potassium limitation of forest productivity – Part 1: A mechanistic model simulating the effects of potassium availability on canopy carbon and water fluxes in tropical eucalypt stands - BG

View Source
Preview of Understanding Your Soil Test (Goulburn Broken CMA, 2016)
Understanding Your Soil Test (Goulburn Broken CMA, 2016) Journal

Understanding Your Soil Test (Goulburn Broken CMA, 2016)

View Source

Supporting Sources (3)

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

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

Potassium | Fact Sheets | soilquality.org.au

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

Potassium for crop production | UMN Extension

View Source

Context

  • Region Australia
  • Biome Arid Inland Floodplains & Ephemeral River Systems
  • Land Use Production Forestry
  • Assessment Conservation Target
  • Vegetation Forest
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 9 Jun 2026

Notes

Lower Critical Threshold: 120 mg/kg. Upper Detrimental Threshold: 950 mg/kg. This benchmark reflects potassium sufficiency that supports drought resilience and growth in the arid inland floodplains biome. The upper boundary is set to avoid nutrient imbalances caused by excessive potassium relative to calcium and magnesium.