Soil Potassium

AUS-AIF-FOR-SOK General Moderate confidence

Benchmark Value

120 mg/kg
Direction: Higher is desirable ↑
Form: MinimumOnly

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context.

Evidence & Context

A lower critical threshold of approximately 120 mg/kg of available potassium is proposed for the clay and loam soils characteristic of the arid inland floodplains.

Metric Definition:

Lower critical threshold of available soil potassium below which forest ecosystem health and productivity are compromised.

Benchmark Definition:

This benchmark represents the critical minimum potassium concentration below which forest health and productivity are likely to be significantly compromised in the arid inland floodplains biome.

Justification:

Based on tree physiology research and NSW pasture legume deficiency thresholds.

Sources (2)

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

Supporting Sources (4)

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
Preview of Understanding Your Soil Test (Goulburn Broken CMA, 2016)
Understanding Your Soil Test (Goulburn Broken CMA, 2016)
Direct Evidence Journal

Understanding Your Soil Test (Goulburn Broken CMA, 2016)

View Source

Context

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

Lifecycle

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

Notes

Below this threshold, essential functions like drought resistance and growth are likely impaired.