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 6 benchmarks together — the OptimalRange form drives the primary score, while 5 guard(s) constrain the result.
Contributing Benchmarks
Evidence & Context
A Lower Critical Threshold is identified at a soil pH(CaCl₂) of less than 5.0 (approximately equivalent to pH(water) < 5.7), below which aluminium toxicity begins to severely compromise ecosystem function and indicates a degraded, acidified state.
Soil pH measured in a 1:5 soil-to-water solution (pHw) in the topsoil layer (0-10 cm).
Lower critical soil pH threshold below which ecosystem function is severely compromised due to aluminium toxicity.
Based on scientific literature linking pH(CaCl₂) < 5.0 (approx. pH(water) < 5.7) to aluminium toxicity and ecosystem degradation.
Sources (1)
Soil and Landscape Grid National Soil Attribute Maps - pH - Calcium Chloride (3" resolution) - Release 2 - TERN Data Discovery Portal
View SourceSupporting Sources (4)
Additional references from the underlying research that informed this benchmark.
Caritat, P. de, & Cooper, M. (2011). The pH of Australian soils: Field results from a national survey. Soil Research, 49, 172-182.
View SourceSoil and Landscape Grid National Soil Attribute Maps - pH (Water) (3" resolution) - Release 1. v2
View SourceSoil and Landscape Grid of Australia - CSIRO
View SourceSoil pH Explained - Soil Quality Knowledge Base
View Source