Microbial Biomass Carbon (MBC)

AUS-TDG-LVG-SMB General Moderate confidence

Benchmark Value

400.2 mg/kg

Direction: Higher is desirable ↑

Form: Point

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 13 benchmarks together — the OptimalRange form drives the primary score, while 12 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The selected benchmark reference value is 400.2 mg/kg, derived from a perennial pasture system in Pampas, QLD, which demonstrated superior soil biological health compared to adjacent cropping systems.9

Metric Definition:

Microbial Biomass Carbon (MBC) is the carbon contained within the living cells of microorganisms in the soil, primarily bacteria and fungi.

Benchmark Definition:

This benchmark represents the microbial biomass carbon level in soil indicating superior soil biological health in Temperate Dry Woodlands & Native Grasslands under livestock grazing and pasture management.

Justification:

This value is chosen as the best available proxy for a high-health managed grazing landscape in Australia due to its direct field measurement in a relevant agricultural research context and its association with less soil disturbance and more consistent organic matter inputs.

Supporting Sources (19)

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

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

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

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

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 Journal

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.

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

Variation in soil microbial biomass in the dry tropics: impact of land-use change, accessed on June 7, 2025,

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)

Direct Evidence

Farming systems can affect soil biology, soil pathogens and system ...

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

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

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

Direct Evidence Journal

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

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 Journal

(PDF) Soil organic carbon stocks in saline and sodic landscapes

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

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

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

Managing Grazing to Restore Soil Health, Ecosystem Function, and Ecosystem Services - Frontiers

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 GreyLiterature

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

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

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

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 GreyLiterature

Responses of soil labile organic carbon stocks and the carbon pool management index to different vegetation restoration types in the Danxia landform region of southwest China - PMC - PubMed Central

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 Carbon Pool as Influenced by Soil Microbial Activity—An Overview

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

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

Context

Region Australia
Biome Temperate Dry Woodlands & Native Grasslands
Land Use Livestock Grazing & Pasture
Assessment Not Stated
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 3 Jun 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. The value represents a demonstrably superior condition relative to more intensive land uses at the same location. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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