Microbial Biomass Carbon (MBC)

AUS-TSW-LVG-SMB General Moderate confidence

Benchmark Value

700 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

Based on this evidence, the value of 700 mg/kg is selected as the primary "best-on-offer" reference value for Microbial Biomass Carbon in this land use context.

Metric Definition:

Microbial Biomass Carbon (MBC) represents the total carbon contained within the living cells of soil microorganisms.

Benchmark Definition:

This benchmark represents the highest measured Microbial Biomass Carbon value in temperate semi-arid shrublands and open woodlands under livestock grazing and pasture. It reflects an aspirational target for high soil biological activity under best-practice management.

Justification:

This value represents the highest documented state of soil biological activity achieved within a realistic, well-managed, and productive grazing system.

Sources (1)

Preview of Sustainable Grazing Systems (SGS) Key Program - Final Report
Sustainable Grazing Systems (SGS) Key Program - Final Report Journal

final report - MLA

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of functions-of-soil-organic-matter-and-the-effect-on-soil-properties.pdf.pdf, accessed July 19, 2025,
functions-of-soil-organic-matter-and-the-effect-on-soil-properties.pdf.pdf, accessed July 19, 2025,
Contextual Support Journal

The biodiversity cost of carbon sequestration in tropical savanna - PMC - PubMed Central

View Source
Preview of Impact of agricultural land use on distribution of microbial biomass and activity within soil aggregates - ResearchGate
Impact of agricultural land use on distribution of microbial biomass and activity within soil aggregates - ResearchGate
Contextual Support Journal

Plant responses to livestock grazing frequency in an Australian temperate grassland, accessed August 8, 2025,

View Source
Preview of Managing grazing to increase ground cover in rangelands: using remote sensing to detect change - CSIRO Publishing, accessed July 18, 2025,
Managing grazing to increase ground cover in rangelands: using remote sensing to detect change - CSIRO Publishing, accessed July 18, 2025,
Contextual Support Journal

Managing grazing to increase ground cover in rangelands: using remote sensing to detect change - CSIRO Publishing

View Source

Context

  • Region Australia
  • Biome Temperate Semi-Arid Shrublands & Open Woodlands
  • Land Use Livestock Grazing & Pasture
  • Assessment Not Stated
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 5 Jun 2026

Notes

No evidence supports a detrimental upper threshold for Microbial Biomass Carbon in this context. The upper limit is a natural saturation point dictated by climate and soil type, not a point of ecological harm. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.