Soil pH

AUS-TDG-AGR-SPH General Moderate confidence

Benchmark Value

No specific value — see range
Range: 5.5 to 6 pH
Optimal Range: 5.5 to 6
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 2 benchmarks together — the OptimalRange form drives the primary score, while 1 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard

Evidence & Context

A reference range of pH(CaCl₂) 5.5 – 6.0 is proposed as the best available condition for sustainable cropping systems aiming for high environmental health.

Metric Definition:

Soil pH measured in a 0.01M calcium chloride solution (pH(CaCl₂)) representing soil acidity affecting nutrient availability, microbial activity, and crop health in agricultural cropping systems.

Benchmark Definition:

This benchmark defines the optimal soil pH range for sustainable agricultural cropping in temperate dry woodlands and native grasslands, balancing soil acidity and ecological health.

Justification:

Derived from synthesis of native ecosystem soil pH data (McIntyre et al., 2010) and sustainable agriculture pH guidelines (GRDC, 2016), balancing amelioration of natural acidity and maintenance of soil ecological health.

Sources (2)

Preview of McIntyre, S., Stol, J., Harvey, J., Nicholls, A.O., Campbell, M., Reid, A., Manning, A.D. & Lindenmayer, D. (2010). Biomass and floristic patterns in the ground layer vegetation of box-gum grassy eucalypt woodland in Goorooyarroo and Mulligans Flat Nature Reserves, Australian Capital Territory. Cunninghamia 11(3): 319–357.
McIntyre, S., Stol, J., Harvey, J., Nicholls, A.O., Campbell, M., Reid, A., Manning, A.D. & Lindenmayer, D. (2010). Biomass and floristic patterns in the ground layer vegetation of box-gum grassy eucalypt woodland in Goorooyarroo and Mulligans Flat Nature Reserves, Australian Capital Territory. Cunninghamia 11(3): 319–357. Journal

McIntyre, S., Stol, J., Harvey, J., Nicholls, A.O., Campbell, M., Reid, A., Manning, A.D. & Lindenmayer, D. (2010). Biomass and floristic patterns in the ground layer vegetation of box-gum grassy eucalypt woodland in Goorooyarroo and Mulligans Flat Nature Reserves, Australian Capital Territory. Cunninghamia 11(3): 319–357.

View Source
Preview of SECTION 5 Wheat - Nutrition and fertiliser - GRDC, accessed July 8, 2025
SECTION 5 Wheat - Nutrition and fertiliser - GRDC, accessed July 8, 2025 Journal

Grains Research and Development Corporation (GRDC). (2016). GrowNote Wheat South 05 Nutrition.

View Source

Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Agricultural Crop Production
  • Assessment Conservation Target
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 10 Jun 2026

Notes

Lower Critical Threshold: pH(CaCl₂) <4.7 increases Al/Mn toxicity risks and compromises microbial health. Optimal Range: 5.5-6.5 supports nutrient availability and microbial activity. Upper Detrimental Threshold: >7.0 may reduce microbial benefits and cause nutrient imbalances; associated with tree dieback in temperate grasslands.