Microbial Biomass Carbon (MBC)

AUS-AKW-LVG-SMB General Moderate confidence

Benchmark Value

No specific value — see range
Range: 200 to 350 mg/kg
Optimal Range: 200 to 350
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

The primary benchmark for a healthy, functional system under best-practice regenerative grazing is an MBC value in the range of 200 – 350 mg C/kg soil (0-10 cm depth).

Metric Definition:

Microbial Biomass Carbon (MBC)

Benchmark Definition:

This benchmark defines the healthy range of microbial biomass carbon in soil under conservation-focused grazing management in arid karstic woodlands and shrublands, indicating a functional soil ecosystem.

Justification:

Derived by triangulating values from semi-arid Western Australian systems, well-managed Queensland pastures, and international rangeland and karst studies.

Sources (7)

Preview of Characterization of Microbial Carbon Metabolism in Karst Soils from Citrus Orchards and Analysis of Its Environmental Drivers - MDPI
Characterization of Microbial Carbon Metabolism in Karst Soils from Citrus Orchards and Analysis of Its Environmental Drivers - MDPI Journal

Characterization of Microbial Carbon Metabolism in Karst Soils from Citrus Orchards and Analysis of Its Environmental Drivers - MDPI

View Source
Preview of Microbial Biomass Carbon - NSW | Fact Sheets | soilquality.org.au, accessed August 5, 2025,
Microbial Biomass Carbon - NSW | Fact Sheets | soilquality.org.au, accessed August 5, 2025, GreyLiterature

www.soilquality.org.au

View Source
Preview of Microbial biomass carbon and some soil properties as influenced by long-term sodic-water irrigation, gypsum, and organic amendments - CSIRO Publishing
Microbial biomass carbon and some soil properties as influenced by long-term sodic-water irrigation, gypsum, and organic amendments - CSIRO Publishing Journal

Microbial biomass carbon and some soil properties as influenced by long-term sodic-water irrigation, gypsum, and organic amendments - CSIRO Publishing

View Source
Preview of Soil carbon sequestration in rangelands: a critical review of the impacts of major management strategies - CSIRO Publishing, accessed August 5, 2025,
Soil carbon sequestration in rangelands: a critical review of the impacts of major management strategies - CSIRO Publishing, accessed August 5, 2025, Journal

Synthesis of Australian Rangeland SOC Data from CSIRO, Peer-Reviewed Literature, and Government Reports

View Source
Preview of Soil carbon sequestration in rangelands: A critical review of the impacts of major management strategies - ResearchGate, accessed August 5, 2025,
Soil carbon sequestration in rangelands: A critical review of the impacts of major management strategies - ResearchGate, accessed August 5, 2025, GreyLiterature

Soil carbon sequestration in rangelands: A critical review of the impacts of major management strategies - ResearchGate, accessed July 23, 2025

View Source
Preview of Soil Microbial Biomass Carbon and Nitrogen in Himalayan Rangeland of Eastern Nepal: A Comparison between Grazed and Non-grazed Rangelands - ResearchGate
Soil Microbial Biomass Carbon and Nitrogen in Himalayan Rangeland of Eastern Nepal: A Comparison between Grazed and Non-grazed Rangelands - ResearchGate Journal

Soil Microbial Biomass Carbon and Nitrogen in Himalayan Rangeland of Eastern Nepal: A Comparison between Grazed and Non-grazed Rangelands - ResearchGate

View Source
Preview of Soil microbial biomass—Interpretation and consideration for soil monitoring - ResearchGate, accessed August 5, 2025,
Soil microbial biomass—Interpretation and consideration for soil monitoring - ResearchGate, accessed August 5, 2025, Journal

Soil microbial biomass—Interpretation and consideration for soil monitoring - ResearchGate

View Source

Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Livestock Grazing & Pasture
  • Assessment Conservation Target
  • Vegetation Woodland
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 4 Jun 2026

Notes

Measured in the 0-10 cm soil layer.