Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 5.5 to 6.5 pH

Optimal Range: 5.5 to 6.5

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

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard OptimalRange Guard Point Guard LowerThreshold Guard LowerThreshold Guard OptimalRange Guard LowerThreshold Guard UpperThreshold Guard Point Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard OptimalRange Guard LowerThreshold Guard UpperThreshold Guard

Evidence & Context

Therefore, a more realistic optimal range, considering the inherent characteristics of these ecosystems and the need to balance productivity with ecological integrity, is proposed as pH 5.5 to 6.5 (1:5 soil:water).

Metric Definition:

Soil pH measured as a 1:5 soil:water suspension

Benchmark Definition:

This benchmark represents a realistic optimal soil pH range for production forestry in Australian alpine and subalpine ecosystems, supporting vigorous tree growth and ecological balance.

Justification:

This range is conducive to vigorous growth of species like Eucalyptus delegatensis; good nutrient availability; minimized Al/Mn toxicity; healthy microbial activity. Upper end (6.5) acknowledges natural ecosystem constraints.

Sources (1)

Preview of (PDF) The pH of Australian soils: field results from a national survey - ResearchGate, accessed July 25, 2025,

(PDF) The pH of Australian soils: field results from a national survey - ResearchGate, accessed July 25, 2025, Journal

Soil pH | Environment, land and water - Queensland Government, accessed August 28, 2025,

View Source

Context

Region Australia
Biome Alpine and Subalpine Complex
Land Use Production Forestry
Assessment Pristine Reference
Evidence Type TargetCondition

Lifecycle

Status Superseded
Version 2
Effective From 24 Mar 2026
Effective To 24 Mar 2026

Notes

The upper end of this range is rarely encountered naturally and maintaining it could be ecologically detrimental or unsustainable.

Related Benchmarks

Other benchmarks in the AUS-ASC-FOR-SPH family.