Soil pH
Benchmark Value
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
Evidence & Context
The critical threshold can be set at approximately pH(CaCl₂) 5.0, with severe impacts intensifying as the pH drops below pH(CaCl₂) 4.8.
Soil pH measured in 0.01M calcium chloride solution (pHCaCl₂), indicating onset of aluminum toxicity affecting root function.
This benchmark defines the lower critical soil pH threshold indicating the onset of aluminum toxicity that impairs root function and plant growth in the Arid Mountain Ranges & Uplands biome under production forestry.
This threshold is supported by widespread evidence including national assessments and agricultural extension advice.
Sources (2)
Soil acidity - Department for Environment and Water, accessed July 30, 2025,
View SourceSoil acidity is starting to emerge in the Southern Mallee on certain soils types. - GRDC, accessed July 30, 2025,
View SourceSupporting Sources (3)
Additional references from the underlying research that informed this benchmark.
Northern Mount Lofty Ranges and Southern Flinders Ranges soil descriptions.
View Source
Peppermint Box (Eucalyptus odorata) Grassy Woodland of South Australia, accessed July 30, 2025,
View SourceSoil pH - SA | Fact Sheets | soilquality.org.au, accessed July 30, 2025,
View Source