Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 5 to 6.5 pH

Optimal Range: 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 13 benchmarks together — the OptimalRange form drives the primary score, while 12 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Therefore, an optimal soil pH range of pH_CaCl2 5.0 to 6.5 (equivalent to approximately pH_w 5.8 to 7.3) is proposed for sustainable production forestry in this biome.

Metric Definition:

Soil pH measured in 0.01M calcium chloride solution (pH_CaCl2), indicating the chemical balance crucial for soil health and vegetation growth.

Benchmark Definition:

Optimal soil pH range for maintaining soil health, nutrient availability, and minimizing toxicity for adapted species in sustainable production forestry on typical tropical monsoonal savanna soils.

Justification:

The range is based on general soil science principles, plant physiological requirements, and regional soil characteristics relevant to Australian Tropical Monsoonal Savannas, balancing ecological integrity with sustainable production.

Sources (1)

Preview of Horiba (2018) Soil pH and Nutrient Availability

Horiba (2018) Soil pH and Nutrient Availability GreyLiterature

Soil Acidity - Land degradation in Australia, accessed July 20, 2025,

View Source

Supporting Sources (6)

Additional references from the underlying research that informed this benchmark.

(PDF) Soil acidification and natural resource management ..., accessed May 16, 2025,

Contextual Support GreyLiterature

(PDF) Soil acidification and natural resource management ..., accessed May 16, 2025

View Source

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

Contextual Support Journal

Caritat, P. de, & Cooper, M. (2011). The pH of Australian soils: Field results from a national survey. Soil Research, 49, 172-182.

View Source

Helyar Porter (1989) Soil acidification, its measurement and the processes involved (in S8)

Direct Evidence

Kaur et al. (2005) Impact of tree clearing on soil pH.

View Source

Preview of Multiple soil element and pH interactions constrain plant performance on tropical soils with a long history of fire - CSIRO PUBLISHING | Soil Research, accessed May 16, 2025,

Multiple soil element and pH interactions constrain plant performance on tropical soils with a long history of fire - CSIRO PUBLISHING | Soil Research, accessed May 16, 2025,

Contextual Support Direct Evidence Journal

Soil Research - CSIRO PUBLISHING

View Source

Preview of Using digital photography to monitor changes in biocrusts and ground cover in a savanna rangeland - CSIRO Publishing, accessed May 16, 2025,

Using digital photography to monitor changes in biocrusts and ground cover in a savanna rangeland - CSIRO Publishing, accessed May 16, 2025,

Contextual Support Methodology Source Journal

Hunt, L. P., Petty, S., Cowley, R., Fisher, A., Ash, A., & MacDonald, N. (2014). Principles and guidelines for managing cattle grazing in the grazing lands of northern Australia: stocking rates, pasture resting, prescribed fire, paddock size and water points – a review. Rangeland Journal, 36(2), 109-130.

View Source

www.publications.qld.gov.au, accessed May 16, 2025,

Contextual Support Journal

The Soils of Cape York Peninsula. Cooktown and Weipa Sections. Land Resource Survey and Evaluation.

View Source

Context

Region Australia
Biome Tropical Monsoonal Savannas
Land Use Production Forestry
Assessment Not Stated
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 1 Jun 2026

Notes

This range avoids strong acidity and aluminum toxicity, supports nutrient availability, and is achievable with sustainable management on inherently acidic soils without excessive interventions. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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