Microbial Biomass Carbon (MBC)

AUS-TDG-LVG-SMB General Moderate confidence

Benchmark Value

No specific value — see range
Range: 300 to 750 mg/kg
Optimal Range: 300 to 750
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 11 benchmarks together — the OptimalRange form drives the primary score, while 10 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary OptimalRange Guard MinimumOnly Guard Point Guard OptimalRange Guard MinimumOnly Guard Point Guard Point Guard MinimumOnly Guard OptimalRange Guard MinimumOnly Guard

Evidence & Context

Considering these points, an estimated optimal MBC range for Temperate Dry Woodlands & Native Grasslands under best-practice grazing is tentatively proposed as 300 - 750 mg/kg.

Metric Definition:

Optimal range of Microbial Biomass Carbon (MBC) associated with high ecological function and resilience under sustainable grazing.

Benchmark Definition:

This benchmark represents the optimal microbial biomass carbon range indicating healthy and resilient soil biological activity in Temperate Dry Woodlands & Native Grasslands under best-practice grazing.

Justification:

Based on studies indicating values within this range correspond to good to excellent soil biological health under best-practice grazing.

Sources (2)

Preview of Farming systems can affect soil biology, soil pathogens and system resilience (GRDC Update Paper, Pampas Site Data)
Farming systems can affect soil biology, soil pathogens and system resilience (GRDC Update Paper, Pampas Site Data)

Farming systems can affect soil biology, soil pathogens and system resilience (GRDC Update Paper, Pampas Site Data)

View Source
Preview of grazing impacts on the spatial distribution of soil microbial biomass around tussock grasses in a tropical grassland - Publication : USDA ARS
grazing impacts on the spatial distribution of soil microbial biomass around tussock grasses in a tropical grassland - Publication : USDA ARS Journal

Soil microbial community structure is unaltered by grazing intensity and plant species richness in a temperate grassland steppe in northern China - Publication : USDA ARS, accessed July 29, 2025

View Source

Supporting Sources (17)

Additional references from the underlying research that informed this benchmark.

Preview of Assessing the response of soil carbon in Australia to changing inputs and climate using a consistent modelling framework - BG
Assessing the response of soil carbon in Australia to changing inputs and climate using a consistent modelling framework - BG
Contextual Support Journal

Assessing the response of soil carbon in Australia to changing inputs and climate using a consistent modelling framework - BG

View Source
Preview of Carbon Pool Dynamic and Soil Microbial Respiration Affected by ...
Carbon Pool Dynamic and Soil Microbial Respiration Affected by ...
Contextual Support Journal

Carbon Pool Dynamic and Soil Microbial Respiration Affected by Land Use Alteration: A Case Study in Humid Subtropical Area - MDPI, accessed July 28, 2025,

View Source
Preview of Crop and Pasture Science - CSIRO PUBLISHING
Crop and Pasture Science - CSIRO PUBLISHING
Contextual Support Journal

Temperature response of soil respiration largely unaltered with experimental warming

View Source
Preview of Declining soil pH reduces microbial biomass-driven soil multifunctionality - Institute for Environmental Genomics
Declining soil pH reduces microbial biomass-driven soil multifunctionality - Institute for Environmental Genomics
Contextual Support Journal

Declining soil pH reduces microbial biomass-driven soil multifunctionality - Institute for Environmental Genomics

View Source
Preview of Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - CSIRO Publishing, accessed August 5, 2025,
Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - CSIRO Publishing, accessed August 5, 2025,
Contextual Support

Ludwig, J.A., Bastin, G.N., Chewings, V.H., Eager, R.W., and Liedloff, A.C. (2005). Clearing savannas for use as rangelands in Queensland: Altered landscapes and water-erosion processes. Rangeland Journal, 27(2), 135-149.

View Source
Preview of Effects of heavy metals on soil microbial biomass carbon - ResearchGate, accessed on June 7, 2025,
Effects of heavy metals on soil microbial biomass carbon - ResearchGate, accessed on June 7, 2025,
Contextual Support Journal

Effects of heavy metals on soil microbial biomass carbon - ResearchGate

View Source
Preview of Grazing Impacts on Soil Carbon and Microbial Communities in a Mixed-Grass Ecosystem - USDA ARS
Grazing Impacts on Soil Carbon and Microbial Communities in a Mixed-Grass Ecosystem - USDA ARS
Contextual Support Journal

Grazing Impacts on Soil Carbon and Microbial Communities in a Mixed-Grass Ecosystem - USDA ARS, accessed August 9, 2025

View Source
Preview of HOW TO MEASURE AND INTERPRET RESULTS IN RELATION TO SOIL ORGANIC CARBON - Grains Research and Development Corporation (GRDC), accessed August 5, 2025,
HOW TO MEASURE AND INTERPRET RESULTS IN RELATION TO SOIL ORGANIC CARBON - Grains Research and Development Corporation (GRDC), accessed August 5, 2025,
Contextual Support GreyLiterature

HOW TO MEASURE AND INTERPRET RESULTS IN RELATION TO SOIL ORGANIC CARBON - Grains Research and Development Corporation (GRDC)

View Source
Preview of Impact of Cropping Systems on Macronutrient Distribution and Microbial Biomass in Drought Affected Soils - EGUsphere
Impact of Cropping Systems on Macronutrient Distribution and Microbial Biomass in Drought Affected Soils - EGUsphere
Contextual Support GreyLiterature

GRDC Groundcover Article: National blueprint to standardise soil health across Australian agriculture - The Waite, accessed July 8, 2025

View Source
Preview of Impact of Grazing on Soil Carbon and Microbial Biomass in Typical Steppe and Desert Steppe of Inner Mongolia | PLOS One
Impact of Grazing on Soil Carbon and Microbial Biomass in Typical Steppe and Desert Steppe of Inner Mongolia | PLOS One
Contextual Support Journal

Impact of Grazing on Soil Carbon and Microbial Biomass in Typical Steppe and Desert Steppe of Inner Mongolia | PLOS One

View Source
Preview of Impacts of Rotational Grazing on Soil Carbon in Native Grass-Based ..., accessed August 5, 2025,
Impacts of Rotational Grazing on Soil Carbon in Native Grass-Based ..., accessed August 5, 2025,
Contextual Support Journal

Impacts of Rotational Grazing on Soil Carbon in Native Grass-Based Pastures in Southern Australia | PLOS One - Research journals

View Source
Preview of Impacts of Rotational Grazing on Soil Carbon in Native Grass-Based Pastures in Southern Australia - ResearchGate, accessed August 5, 2025,
Impacts of Rotational Grazing on Soil Carbon in Native Grass-Based Pastures in Southern Australia - ResearchGate, accessed August 5, 2025,
Contextual Support Journal

Grazing management for soil carbon in Australia: A review - ResearchGate

View Source
Preview of Removing Grazing Pressure from a Native Pasture Decreases Soil Organic Carbon in Southern New South Wales, Australia - ResearchGate
Removing Grazing Pressure from a Native Pasture Decreases Soil Organic Carbon in Southern New South Wales, Australia - ResearchGate
Contextual Support

Removing Grazing Pressure from a Native Pasture Decreases Soil Organic Carbon in Southern New South Wales, Australia - ResearchGate

View Source
Preview of Soil Carbon Pool as Influenced by Soil Microbial Activity—An Overview, accessed on June 7, 2025,
Soil Carbon Pool as Influenced by Soil Microbial Activity—An Overview, accessed on June 7, 2025,
Contextual Support Journal

Soil Carbon Pool as Influenced by Soil Microbial Activity—An Overview

View Source
Preview of Soil microbial biomass—what do the numbers really mean? - ResearchGate, accessed August 28, 2025,
Soil microbial biomass—what do the numbers really mean? - ResearchGate, accessed August 28, 2025,
Contextual Support

Soil microbial biomass carbon and CO2? - ResearchGate, accessed July 18, 2025,

View Source
Preview of Soil microbial carbon and activity along with land use and geographic gradients
Soil microbial carbon and activity along with land use and geographic gradients
Contextual Support

Soil microbial carbon and activity along with land use and geographic gradients

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Preview of Soil quality and health in pasture systems - Holbrook Landcare Network
Soil quality and health in pasture systems - Holbrook Landcare Network
Contextual Support Journal

Soil quality and health in pasture systems - Holbrook Landcare ...

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Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Evidence Type HealthyOperationalRange

Lifecycle

  • Status Active
  • Version 2
  • Effective From 17 Mar 2026

Notes

Values towards the upper end signify very good to excellent soil biological health and efficient ecosystem functioning.

Related Benchmarks

Other benchmarks in the AUS-TDG-LVG-SMB family.

400.2 mg/kg Moderate
Livestock Grazing & Pasture · Pristine Reference
Point Retired v1
— mg/kg Moderate
Livestock Grazing & Pasture · Pristine Reference
OptimalRange Superseded v1