Soil Potassium

AUS-AIF-CON-SOK General Moderate confidence

Benchmark Value

No specific value — see range

Range: 50 to 100 mg/kg

Optimal Range: 50 to 100

Direction: Higher is desirable ↑

Form: OptimalRange

Scoring Curve

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

Evidence & Context

Therefore, for sandy and loamy soil inclusions (e.g., Tenosols, Kandosols) within the Arid Inland Floodplains biome under conservation management, a benchmark range of 50 - 100 mg/kg (Colwell K) is proposed.

Metric Definition:

Available soil potassium measured as Colwell K, representing plant-available potassium in soil.

Benchmark Definition:

Benchmark range for available soil potassium in sandy and loamy soils representing the best available natural condition.

Justification:

Based on agronomic critical values for wheat yield and ecological inference to ensure resilience in less fertile soils.

Sources (2)

Preview of (PDF) Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia - ResearchGate, accessed July 18, 2025,

(PDF) Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia - ResearchGate, accessed July 18, 2025, Journal

Nutrient Cycling in Australian Savannas on JSTOR - DOI

View Source

Availability of soil potassium and diagnostic soil tests - DPI eResearch Archive (eRA) Journal

Availability of soil potassium and diagnostic soil tests - DPI eResearch Archive (eRA)

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia

Direct Evidence

Soil potassium—crop response calibration relationships and criteria for field crops grown in Australia

View Source

Context

Region Australia
Biome Arid Inland Floodplains & Ephemeral River Systems
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 10 Jun 2026

Notes

Lower Critical Threshold: 40 mg/kg. No upper detrimental threshold — higher values are always better up to natural saturation. No upper detrimental threshold identified; upper boundary reflects lower inherent fertility and K-holding capacity of these soils. Lower critical threshold is <40 mg/kg indicating potential ecosystem stress.

Related Benchmarks

Other benchmarks in the AUS-AIF-CON-SOK family.