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
A lower critical threshold of pH(water) 5.0 is established. Below this value, the risk of multiple, compounding negative impacts—including aluminum and manganese toxicity, impaired root function, and reduced microbial activity—becomes unacceptably high.
Soil pH measured in water at a 1:5 soil to water ratio in the top 0-10 cm of soil.
The critical lower pH threshold below which ecosystem function is impaired due to toxicity and other negative effects in tropical and subtropical rainforest production forestry soils.
Below this value, the risk of aluminum and manganese toxicity increases significantly, inhibiting root growth and impairing microbial function, thereby compromising long-term forest productivity and health.
Sources (1)
Supporting Sources (4)
Additional references from the underlying research that informed this benchmark.
Soil acidity | Soil | Farm management - Agriculture Victoria, accessed August 28, 2025
View SourceSoil carbon and nutrient pools, microbial properties and gross nitrogen transformations in adjacent natural forest and hoop pine plantations of subtropical Australia - ResearchGate, accessed July 20, 2025
View SourceMultiple soil element and pH interactions constrain plant performance on tropical soils with a long history of fire - CSIRO PUBLISHING | Soil Research, accessed July 20, 2025
View SourceImproving Soil Structure and pH Levels (DPIFM_NT) - Department of ..., accessed July 20, 2025
View Source