Soil pH

AUS-TMS-AGR-SPH General Moderate confidence

Benchmark Value

No specific value — see range
Range: 6 to 6.6 pH
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 4 benchmarks together — the OptimalRange form drives the primary score, while 3 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 the acidity or alkalinity of the soil solution.

Benchmark Definition:

A benchmark range of soil pH representing high environmental health under sustainable agricultural management in tropical monsoonal savannas.

Justification:

The benchmark is supported by recent research at Katherine Research Station and aligns with soil health indicators such as Cation Exchange Capacity (CEC), critical for nutrient retention and ecosystem resilience.

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 literature and expert synthesis

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Context

  • Region Australia
  • Biome Tropical Monsoonal Savannas
  • Land Use Agricultural Crop Production
  • Assessment Agricultural Biodiversity Target
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Superseded
  • Version 1
  • Effective From 10 Jun 2026
  • Effective To 10 Jun 2026

Notes

Lower Critical Threshold: 5 pH. Upper Detrimental Threshold: 7.2 pH. Maintaining pH (CaCl₂) > 6.0 is recommended for improving CEC in sandy, low-CEC soils typical of tropical savannas. The range reflects conditions achievable under best-practice sustainable agriculture.