Soil Potassium

AUS-AMR-AGR-SOK General Moderate confidence

Benchmark Value

40 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. The scoring engine uses 3 benchmarks together — the OptimalRange form drives the primary score, while 2 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MinimumOnly Guard

Evidence & Context

These data indicate that a Colwell K value below approximately 40–50 mg/kg in the topsoil (0-10 cm) represents a functionally impaired state for the major crops grown in this biome.

Metric Definition:

Colwell K value in topsoil (0-10 cm) indicating critical deficiency for 90% relative yield

Benchmark Definition:

This benchmark defines the critical lower threshold of soil potassium in the topsoil for major crops in the Arid Mountain Ranges & Uplands biome under agricultural crop production. Values below 40 mg/kg indicate a functionally impaired state that can reduce crop yield and resilience.

Justification:

Derived from the 'Better Fertiliser Decisions for Crops' dataset calibrated to achieve 90% of maximum relative yield for key dryland crops.

Sources (1)

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

Context

Region Australia
Biome Arid Mountain Ranges & Uplands
Land Use Agricultural Crop Production
Assessment Agricultural Biodiversity Target
Evidence Type DegradationThreshold

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. Represents the absolute minimum potassium level for functional health in cropping systems; below this level, nutrient deficiency stress compromises productivity and resilience.

Related Benchmarks

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