Soil Potassium

AUS-AMR-FOR-SOK General Moderate confidence

Benchmark Value

50 mg/kg
Thresholds: Lower: 50, Upper: —
Direction: Higher is desirable ↑
Form: LowerThreshold

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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Synthesizing data from studies on wheat, pasture, and forestry, a soil level of < 50 mg/kg (Colwell K) represents a clear point of deficiency.

Metric Definition:

Available potassium (Colwell K) in soil

Benchmark Definition:

A soil potassium level below 50 mg/kg is considered critically deficient, compromising forest health, productivity, and drought resilience in Australia's Arid Mountain Ranges & Uplands production forestry.

Justification:

This value serves as a hard lower boundary for a healthy system based on multiple agricultural and ecological studies in Australia.

Sources (1)

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 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

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Preview of Australian dryland soils are acidic and nutrient‐depleted, and have unique microbial communities compared with other drylands - Arid Ecology Lab, accessed August 3, 2025
Australian dryland soils are acidic and nutrient‐depleted, and have unique microbial communities compared with other drylands - Arid Ecology Lab, accessed August 3, 2025
Direct Evidence Government

Beringer, J., et al. 2022. Carbon and water fluxes over a temperate Eucalyptus forest and a tropical wet/dry savanna in Australia. Agricultural and Forest Meteorology 129(3):151-173.

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

Context

  • Region Australia
  • Biome Arid Mountain Ranges & Uplands
  • Land Use Production Forestry
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 25 Mar 2026

Notes

Potassium deficiency below this threshold impairs critical ecological functions including water-use efficiency and disease resistance. No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

Other benchmarks in the AUS-AMR-FOR-SOK family.

— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Active v1
— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Active v1
— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Active v1
— mg/kg Moderate
Production Forestry · Pristine Reference
OptimalRange Active v1