Microbial Biomass Carbon (MBC)

AUS-TMS-LVG-SMB General Moderate confidence

Benchmark Value

No specific value — see range
Range: 360 to 470 mg/kg
Optimal Range: 360 to 470
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.

Evidence & Context

Therefore, the proposed benchmark for Microbial Biomass Carbon (MBC) in the topsoil (0-10 cm) of a tropical monsoonal savanna under best-practice (i.e., light or no) grazing is 360 - 470 mg/kg.

Metric Definition:

Microbial Biomass Carbon (MBC) in the topsoil (0-10 cm) of a tropical monsoonal savanna under best-practice grazing

Benchmark Definition:

Benchmark for Microbial Biomass Carbon (MBC) representing the best available condition in well-managed tropical savanna grazing systems.

Justification:

The benchmark is derived from ecologically analogous Indian savannas as primary Australian studies establish the principle that light/no grazing maximizes MBC but lack absolute values in available literature.

Sources (1)

Preview of The effects of burning and grazing of dry tropical Indian savanna on the level of available nutrient pools and microbial C, N and P
The effects of burning and grazing of dry tropical Indian savanna on the level of available nutrient pools and microbial C, N and P Journal

The effects of burning and grazing of dry tropical Indian savanna on the level of available nutrient pools and microbial C, N and P

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of A Description of the ECCOSAT Experimental Site at Hillgrove near Charters Towers, north Queensland - ResearchGate
A Description of the ECCOSAT Experimental Site at Hillgrove near Charters Towers, north Queensland - ResearchGate
Contextual Support GreyLiterature

A Description of the ECCOSAT Experimental Site at Hillgrove near Charters Towers, north Queensland - ResearchGate

View Source
Preview of Microbiological Indicators for Assessing the Effects of Agricultural Practices on Soil Health: A Review - MDPI, accessed on June 5, 2025
Microbiological Indicators for Assessing the Effects of Agricultural Practices on Soil Health: A Review - MDPI, accessed on June 5, 2025
Contextual Support Journal

Microbiological Indicators for Assessing the Effects of Agricultural Practices on Soil Health: A Review - MDPI, accessed August 13, 2025,

View Source
Preview of Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter - ResearchGate
Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter - ResearchGate
Direct Evidence Journal

Ratio of microbial biomass carbon to soil organic carbon as a sensitive indicator of changes in soil organic matter - ResearchGate

View Source

Context

  • Region Australia
  • Biome Tropical Monsoonal Savannas
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 3
  • Effective From 21 Mar 2026

Notes

No detrimental upper threshold — higher values are always better up to natural saturation. This range encapsulates the mean annual values observed in well-managed, non-degraded systems that are ecologically homologous to the target Australian biome.