Soil Potassium

AUS-TMS-AGR-SOK General Moderate confidence

Benchmark Value

No specific value — see range

Range: 70 to 120 mg/kg

Optimal Range: 70 to 120

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. 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 proposed benchmark for exchangeable potassium in the 0-10 cm soil depth is a range of 70 - 120 mg/kg.

Metric Definition:

Exchangeable potassium concentration in the 0-10 cm soil depth representing best available condition for agricultural crop production under sustainable or regenerative management.

Benchmark Definition:

Proposed reference range for exchangeable potassium in 0-10 cm soil depth indicating high environmental health in agricultural crop production systems.

Justification:

Derived from synthesis of native soil values, agronomic critical minimums, and managed Kandosol soil assessments, reflecting achievable and sustainable potassium levels in tropical monsoonal savanna agricultural soils.

Sources (2)

Fertilisation with P, N and S requires additional Zn for healthy plantation tree growth on low fertility savanna soils - ResearchGate Journal

Fertilisation with P, N and S requires additional Zn for healthy plantation tree growth on low fertility savanna soils - ResearchGate

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Soil potassium—crop response calibration relationships and ... Journal

Soil potassium—crop response calibration relationships and ...

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Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Soil Research - CSIRO PUBLISHING

Contextual Support Journal

Soil Research - CSIRO PUBLISHING

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Context

Region Australia
Biome Tropical Monsoonal Savannas
Land Use Agricultural Crop Production
Assessment Pristine Reference
Evidence Type TargetCondition

Lifecycle

Status Superseded
Version 1
Effective From 24 Mar 2026
Effective To 24 Mar 2026

Notes

Range is above native background (~46 mg/kg) and agronomic critical minimums (~49 mg/kg Colwell K), aiming for nutrient balance and efficient cycling rather than maximum soil test K. No specific upper detrimental threshold identified; excessive K may cause nutrient imbalances and economic inefficiency.

Related Benchmarks

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