Microbial Respiration

AUS-AIF-LVG-SMR General Moderate confidence

Benchmark Value

2 mg/kg/day
Thresholds: Lower: 2, Upper: —
Direction: Higher is desirable ↑
Form: LowerThreshold

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 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary LowerThreshold Guard UpperThreshold Guard OptimalRange Guard Point Guard

Evidence & Context

A basal respiration rate approaching <1–2 mg CO₂-C/kg/day under standardized laboratory conditions would be a strong indicator that a system has entered this degraded state.

Metric Definition:

Basal microbial respiration rate measured as mg CO2-C per kg of soil per day under standardized laboratory conditions.

Benchmark Definition:

Lower critical threshold of basal microbial respiration indicating system degradation in arid inland floodplains and ephemeral river systems under livestock grazing and pasture.

Justification:

This threshold aligns with the aridity index threshold (AI = 0.13) where microbial metabolism fundamentally shifts, indicating a degraded soil system.

Sources (1)

Preview of Soil Respiration | South Dakota Soil Health Coalition, accessed July 30, 2025,
Soil Respiration | South Dakota Soil Health Coalition, accessed July 30, 2025, GreyLiterature

Aridity thresholds of soil microbial metabolic indices along a 3,200 ..., accessed July 19, 2025,

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Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Inherent Factors Affecting Soil Respiration - USDA, accessed July 30, 2025,
Inherent Factors Affecting Soil Respiration - USDA, accessed July 30, 2025,
Contextual Support Journal

Twenty years of progress, challenges, and opportunities in measuring and understanding soil respiration, accessed August 13, 2025,

View Source
Preview of Managing Grazing to Restore Soil Health, Ecosystem Function, and Ecosystem Services
Managing Grazing to Restore Soil Health, Ecosystem Function, and Ecosystem Services
Contextual Support GreyLiterature

Managing Grazing to Restore Soil Health, Ecosystem Function, and Ecosystem Services, accessed July 19, 2025,

View Source
Preview of Soil Respiration in Relation to Ecosystem Types in an Arid Area, accessed July 19, 2025,
Soil Respiration in Relation to Ecosystem Types in an Arid Area, accessed July 19, 2025,
Contextual Support Journal

Soil Respiration in Different Agricultural and Natural Ecosystems in an Arid Region - PLOS

View Source

Context

  • Region Australia
  • Biome Arid Inland Floodplains & Ephemeral River Systems
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 18 Mar 2026

Notes

Below this threshold, the system is severely degraded with low soil organic matter and poor structure.

Related Benchmarks

Other benchmarks in the AUS-AIF-LVG-SMR family.

— mg/kg/day Moderate
Livestock Grazing & Pasture · Pristine Reference
OptimalRange Active v1
15 mg/kg/day Moderate
Livestock Grazing & Pasture · Pristine Reference
UpperThreshold Active v1