Soil Potassium

AUS-TMI-AGR-SOK General Moderate confidence

Benchmark Value

220 mg/kg

Range: 150 to 250 mg/kg

Thresholds: Lower: 80, Upper: —

Optimal Range: 150 to 250

Direction: Higher is desirable ↑

Form: Point

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 15 benchmarks together — the OptimalRange form drives the primary score, while 14 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The benchmark is derived via synthesis, as no direct studies exist for this specific biome/land use. It is anchored by the critical value of 224 mg/kg (rounded to 220 mg/kg) identified for high-yield potato cropping in analogous volcanic Andisols, which aligns with the upper end of optimal ranges (150-300 mg/kg) observed in high-rainfall Australian systems.

Metric Definition:

Available soil potassium concentration representing the best available condition for agricultural crop production in the Tropical and Subtropical Maritime Islands biome.

Benchmark Definition:

A benchmark value for soil potassium concentration indicating a state of high ecological function and nutrient sufficiency in agricultural soils.

Justification:

The benchmark is based on synthesis of evidence from high-rainfall Australian systems and international volcanic soil analogues, reflecting a state of nutrient sufficiency and ecological health.

Sources (1)

Critical Value of Soil Potassium for Potato Crops in Volcanic Soils Journal

Critical Value of Soil Potassium for Potato Crops in Volcanic Soils

View Source

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Potassium | Fact Sheets | soilquality.org.au, accessed August 11, 2025,

Contextual Support Government

Soil fertility in grazing systems: Manage potassium to manage nitrogen - Crops and Soils, accessed July 28, 2025,

View Source

Potassium for high-performing pastures | Nutrient Advantage, accessed July 18, 2025,

Direct Evidence Journal

Potassium for high rainfall pastures - DPIRD's Digital library

View Source

Context

Region Australia
Biome Tropical & Subtropical Maritime Islands
Land Use Agricultural Crop Production
Assessment Pristine Reference
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

Lower Critical Threshold: 80 mg/kg. No upper detrimental threshold — higher values are always better up to natural saturation. Optimal Range: 150-250 mg/kg is considered optimal for ecologically healthy and productive systems on loamy to clay-loam soils.

Related Benchmarks

Other benchmarks in the AUS-TMI-AGR-SOK family.