Soil pH

AUS-TMS-AGR-SPH General Moderate confidence

Benchmark Value

No specific value — see range
Range: 6 to 6.6 pH (CaCl₂)
Optimal Range: 6 to 6.6
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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Evidence & Context

Based on an analysis of available literature pertaining to well-managed agricultural systems within the Australian Tropical Monsoonal Savannas, a benchmark range of pH (0.01M CaCl₂) 6.0 to 6.6 is proposed.

Metric Definition:

Soil pH measured in 0.01M CaCl₂ solution, indicating soil acidity or alkalinity relevant to soil health and crop production.

Benchmark Definition:

Soil pH measured in 0.01M CaCl₂ solution, representing a benchmark range for high environmental health in agricultural systems of the Tropical Monsoonal Savannas biome.

Justification:

This range is considered representative of the 'best-on-offer' condition, reflecting high environmental health achievable under agricultural research conditions that explicitly incorporate sustainability and soil health objectives.

Sources (1)

Preview of Cotton Production and Sustainability in the Northern Territory: A Comprehensive Analysis of Yield, Soil Properties, and Cover Crops (Mwando et al., 2024, In: Proceedings of the 21st Australian Agronomy Conference)
Cotton Production and Sustainability in the Northern Territory: A Comprehensive Analysis of Yield, Soil Properties, and Cover Crops (Mwando et al., 2024, In: Proceedings of the 21st Australian Agronomy Conference) Journal

Cotton Production and Sustainability in the Northern Territory: A Comprehensive Analysis of Yield, Soil Properties, and Cover Crops (Mwando et al., 2024, In: Proceedings of the 21st Australian Agronomy Conference)

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Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of Effects of agricultural management on soil carbon and pH in the Douglas Daly region of the Northern Territory - NT (Book), accessed on June 7, 2025
Effects of agricultural management on soil carbon and pH in the Douglas Daly region of the Northern Territory - NT (Book), accessed on June 7, 2025
Contextual Support Journal

General soil science principles and reviewed literature

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Context

  • Region Australia
  • Biome Tropical Monsoonal Savannas
  • Land Use Agricultural Crop Production
  • Assessment Pristine Reference
  • Evidence Type TargetCondition

Lifecycle

  • Status Superseded
  • Version 1
  • Effective From 25 Mar 2026
  • Effective To 25 Mar 2026

Notes

The range is associated with higher Cation Exchange Capacity (CEC), a key indicator of soil fertility and resilience, particularly in the typically sandy, low-CEC soils of tropical savannas. Maintaining pH (CaCl₂) > 6.0 is recommended for improving CEC in these soils.