Soil Potassium

AUS-TMS-AGR-SOK General Low confidence

Benchmark Value

No specific value — see range

Thresholds: Lower: —, Upper: 150

Direction: Higher is desirable ↑

Form: MaximumOnly

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 primary concerns with excessively high K levels (potentially >150-200 mg/kg without commensurate benefits) relate to induced nutrient imbalances (especially with magnesium and calcium) and economic inefficiency.

Metric Definition:

Upper detrimental threshold of exchangeable potassium concentration in 0-10 cm soil depth above which nutrient imbalances and economic inefficiency occur.

Benchmark Definition:

Upper detrimental threshold indicating level above which potassium causes nutrient imbalances and inefficiency.

Justification:

Based on risk of cation imbalances in low CEC soils and economic inefficiency from excessive K application.

Sources (1)

Soil Research - CSIRO PUBLISHING Journal

Soil Research - CSIRO PUBLISHING

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Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

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

Contextual Support 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 ...

Direct Evidence Journal

Soil potassium—crop response calibration relationships and ...

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Context

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

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

No direct K toxicity threshold identified; concerns are indirect effects and resource waste. ConsistencyResolver applied 2026-03-24 20:07 UTC: LowerThreshold → (check: MinAboveOptimalHigh, rationale: No change needed for LowerThreshold.) [Auto-corrected BenchmarkForm: MinimumOnly → MaximumOnly] ConsistencyResolver applied 2026-03-24 20:07 UTC: UpperThreshold 150 → 150 (check: MinAboveOptimalHigh, rationale: Retain UpperThreshold at 150 mg/kg to represent the upper detrimental threshold; this will auto-correct the form to MaximumOnly.) ConsistencyResolver applied 2026-03-24 20:07 UTC: BenchmarkValue 150 → (check: MinAboveOptimalHigh, rationale: Clear BenchmarkValue to avoid duplication since UpperThreshold is set.)

Related Benchmarks

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