ISO 23611-5:2024

Overview

ISO 23611-5:2024 - "Soil quality - Sampling of soil invertebrates - Part 5: Sampling and extraction of soil macro‑invertebrates" specifies a standardized method for collecting, extracting and preserving soil macro‑invertebrates (organisms >10 mm) from soil and the litter zone. The standard supports rapid, repeatable field sampling across most soil types (excluding hard, frozen or flooded soils and non‑soil matrices) and is intended for biodiversity assessment, soil quality evaluation and long‑term monitoring.

Key topics and technical requirements

• Scope & applicability: Sampling and extraction of macro‑invertebrates in litter and upper soil layers; not intended for extreme climatic soils or non‑soil substrates.
• Sampling principle: Delimit a sampling point using a metallic frame (preferably 250 × 250 mm), collect litter separately, extract soil fauna using chemical extraction and hand‑sorting.
• Extraction methods:
  • Formalin extraction (temperate regions): apply 0.2% formalin solution (two applications ~1.5 L each, ~10 min apart) to drive fauna to the surface for collection.
  • Hand‑sorting: excavate the upper soil (upper 150 mm within frame) and manually sort soil and litter for remaining macro‑invertebrates; in tropical regions the formalin step may be omitted and hand‑sorting alone used.
  • Pitfall traps: procedures and monitoring examples provided in informative Annexes B and C.
• Reagents & preservation:
  • Extraction reagent: 0.2% formalin for field extraction.
  • Specimen preservation: 4% formalin for initial fixation (especially soft‑bodied taxa), with transfer to 70% ethanol after ~4 days where appropriate; 70% ethanol also used for longer‑term storage.
• Apparatus: list includes metallic frame, watering can, spade/trowel, trays, vials, forceps, balances and field data recording materials.
• Laboratory steps: sample treatment, preservation, biomass determination and reporting guidance are specified.
• Data & reporting: abundance recalculated per unit area (e.g., per m2); test report elements and assessment are described.

Applications and users

ISO 23611-5:2024 is relevant for:

• Soil scientists, ecologists and taxonomists conducting macro‑fauna inventories
• Environmental consultants and regulators performing soil quality assessments and pollution impact studies
• Agricultural researchers and land managers monitoring effects of land‑use and management practices
• Long‑term biodiversity monitoring programs and soil bio‑indicator studies

Practical benefits include consistent, comparable data across sites and studies, enabling reliable evaluation of soil health, ecosystem engineering activity (e.g., earthworms, arthropods) and responses to disturbance.

Related standards

• ISO 23611 series (other parts cover earthworms and sampling design - see ISO 23611‑1 and ISO 23611‑6)
• Associated soil characterization standards referenced for site physico‑chemical context: ISO 10390, ISO 10694, ISO 11274, ISO 11277, ISO 11461, ISO 11465

Keywords: ISO 23611-5:2024, soil quality, sampling of soil invertebrates, soil macro-invertebrates, formalin extraction, hand-sorting, pitfall traps, biodiversity monitoring.