Soil Potassium

AUS-TSR-CON-SOK General Moderate confidence

Benchmark Value

No specific value — see range

Range: 100 to 300 mg/kg

Optimal Range: 100 to 300

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

The optimal range represents a state where potassium is not a limiting factor for any key ecological process, allowing the ecosystem to function at its full potential.

Metric Definition:

Colwell K value representing plant-available potassium in soil

Benchmark Definition:

This benchmark represents the optimal functional range of plant-available potassium in soils within tropical and subtropical rainforest conservation areas, where potassium is sufficient to support full ecosystem function.

Justification:

Derived from agricultural guides defining 'Adequate' or 'Ideal' levels for high-production systems and natural saturation points characteristic of fertile soil types.

Sources (1)

Understanding soil tests for pastures | Soil | Farm management ..., accessed May 12, 2025 Government

Understanding soil tests for pastures

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Potassium | Fact Sheets | soilquality.org.au

Direct Evidence Government

Potassium | Fact Sheets | soilquality.org.au

View Source

Rainforest – Processes (Department of the Environment, Tourism ..., accessed July 20, 2025,

Direct Evidence Government

Nutrient distribution and cycling in a subtropical rainforest in New South Wales

View Source

TROPICAL SOILS | Terrain NRM, accessed July 16, 2025,

Direct Evidence Journal

Water Retention - Oz Soils 4 - UNE, accessed May 11, 2025,

View Source

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type HealthyOperationalRange

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

The optimal range varies by soil texture class: Sands (101–150 mg/kg), Sandy Loams (121–200 mg/kg), Clay Loams (161–250 mg/kg), Clays (181–300 mg/kg). No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

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