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 19 benchmarks together — the OptimalRange form drives the primary score, while 18 guard(s) constrain the result.
Contributing Benchmarks
Evidence & Context
Considering this evidence, a lower critical threshold of pH(CaCl₂) 4.5 is proposed. Below this level, the likelihood and severity of aluminium and manganese toxicities increase substantially for a broader range of plant species, including many native ones.
Soil pH measured in 0.01 M calcium chloride (CaCl₂) solution, indicating the acidity level below which ecological function is impaired.
Based on evidence of increased toxicity and nutrient limitations below pH 4.5, supported by agricultural and ecological literature.
Sources (2)
Agriculture Victoria. (2025). Soil acidity. Farm Management.
View SourceManage soil acidity | EverGraze More livestock from perennials, accessed July 18, 2025,
View SourceSupporting Sources (3)
Additional references from the underlying research that informed this benchmark.
Soil acidity - Department for Environment and Water
View SourceProber, S.M., Thiele, K.R. and Lunt, I.D. (2002). Determining reference conditions for management and restoration of temperate grassy woodlands: relationships among trees, topsoils and understorey flora in little-grazed remnants. Australian Journal of Botany, 50(6), 687-697.
View SourceSoil Quality Knowledge Base. (n.d.). Soil pH.
View Source