Microbial Biomass Carbon (MBC)

AUS-TGP-CON-SMB General Low confidence

Benchmark Value

536 mg/kg

Direction: Higher is desirable ↑

Form: Point

Scoring Curve

Scoring curve unavailable

The scoring engine could not generate a curve for this benchmark context. The primary form is CompositeFramework, but the benchmark data may be missing required fields (e.g., optimal range bounds for an OptimalRange benchmark). This is typically a data quality issue in the benchmark pipeline.

Contributing Benchmarks

CompositeFramework Primary Point Guard MinimumOnly Guard Point Guard

Evidence & Context

The recommended benchmark value is 536 mg/kg for topsoil (0–10 cm).

Metric Definition:

Microbial Biomass Carbon (MBC) in the topsoil (0–10 cm) of Australian Temperate Grassy Woodlands & Plains under conservation management.

Benchmark Definition:

This benchmark represents a scientifically defensible reference value for Microbial Biomass Carbon (MBC) in the topsoil of Temperate Grassy Woodlands & Plains in Australia under conservation management, indicating the best available natural condition achievable in this landscape.

Justification:

Derived from a comprehensive global meta-analysis for the temperate broadleaf forest biome, corroborated by independent Australian studies showing similar MBC levels in high-carbon temperate pasture soils.

Sources (1)

A global analysis of soil microbial biomass carbon, nitrogen and phosphorus in terrestrial ecosystems Journal

A global analysis of soil microbial biomass carbon, nitrogen and phosphorus in terrestrial ecosystems

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

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

View Source

Microbial biomass and microbial biodiversity in some soils from New South Wales, Australia - CSIRO PUBLISHING | Soil Research

Contextual Support Journal

Microbial biomass and microbial biodiversity in some soils from New South Wales, Australia - CSIRO PUBLISHING | Soil Research, accessed August 12, 2025

View Source

Preview of Restoring ecological function in temperate grassy woodlands: Manipulating soil nutrients, exotic annuals and native perennial grasses through carbon supplements and spring burns | Request PDF - ResearchGate, accessed May 12, 2025

Restoring ecological function in temperate grassy woodlands: Manipulating soil nutrients, exotic annuals and native perennial grasses through carbon supplements and spring burns | Request PDF - ResearchGate, accessed May 12, 2025

Direct Evidence GreyLiterature

Increasing and declining native species in urban remnant grasslands respond differently to nitrogen addition and disturbance

View Source

Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 3 Jun 2026

Notes

No upper detrimental threshold for MBC exists; abnormally high levels can indicate nutrient pollution and a degraded state. A lower critical threshold is functionally represented by a significant decline (>70%) from the benchmark, indicating collapse in soil biological function. Optimal state characterized by MBC levels approaching this benchmark with a high microbial quotient (MBC:SOC>2%) and a resilient native plant community.

Related Benchmarks

Other benchmarks in the AUS-TGP-CON-SMB family.