Soil Potassium

AUS-TSR-CON-SOK General Low confidence

Benchmark Value

100 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

For a protected rainforest on sandy soils, a value greater than 100 mg/kg would indicate a robust system with healthy nutrient cycling.

Metric Definition:

Colwell K value representing plant-available potassium in soil

Benchmark Definition:

This benchmark represents the minimum plant-available potassium level indicating a robust nutrient cycling system in low-fertility sandy soils within tropical and subtropical rainforest conservation areas.

Justification:

Represents a healthy state for naturally low-CEC soils, based on 'ideal' ranges for sandy soils in productive systems.

Sources (1)

Preview of TROPICAL SOILS | Terrain NRM, accessed July 16, 2025,
TROPICAL SOILS | Terrain NRM, accessed July 16, 2025, Journal

A Revegetation Guide for Sub-Tropical Forest - Greening Australia, accessed July 20, 2025,

View Source

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

Preview of Australian Journal of Soil Research - CSIRO Publishing, accessed August 5, 2025
Australian Journal of Soil Research - CSIRO Publishing, accessed August 5, 2025
Direct Evidence

Australian Journal of Soil Research - CSIRO Publishing, accessed July 22, 2025

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Preview of Potassium | Fact Sheets | soilquality.org.au
Potassium | Fact Sheets | soilquality.org.au
Direct Evidence Government

Potassium | Fact Sheets | soilquality.org.au

View Source
Preview of Rainforest – Processes (Department of the Environment, Tourism ..., accessed July 20, 2025,
Rainforest – Processes (Department of the Environment, Tourism ..., accessed July 20, 2025,
Direct Evidence Government

Sediments and nutrients in north Queensland tropical streams ...

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

Agriculture Victoria. (2025). Understanding soil tests for pastures. Farm Management.

View Source

Context

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

Lifecycle

  • Status Superseded
  • Version 1
  • Effective From 9 Jun 2026
  • Effective To 9 Jun 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. Values between 50–100 mg/kg may still indicate good health in these oligotrophic environments.

Related Benchmarks

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

50 mg/kg Low
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Active v4
— mg/kg Moderate
Conservation / Protected Natural Areas · Conservation Target · Forest
OptimalRange Active v2
300 mg/kg High
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Active v2
250 mg/kg Low
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Active v2
100 mg/kg Low
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Superseded v3
50 mg/kg Low
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Superseded v2
120 mg/kg Low
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Rejected v2
— mg/kg Moderate
Conservation / Protected Natural Areas · Conservation Target · Forest
OptimalRange Superseded v1
300 mg/kg High
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Superseded v1
250 mg/kg Low
Conservation / Protected Natural Areas · Conservation Target · Forest
MinimumOnly Superseded v1