Overview
EN ISO 11063:2020 - Soil quality: Direct extraction of soil DNA specifies a standardized laboratory method for the direct extraction of DNA from soil to analyse the abundance and composition of microbial communities. Designed primarily for agricultural and forest soils, the method supports downstream molecular biology techniques including real-time quantitative PCR (qPCR) and next‑generation sequencing (NGS) of PCR amplicons. The standard replaces EN ISO 11063:2013 and refines steps to improve DNA recovery and representativeness of bacterial, archaeal and fungal communities. Note: the procedure may be unsuitable for soils very rich in organic matter (peat) or heavily polluted with organic contaminants or heavy metals.
Key topics and technical requirements
- Sample size and handling
- Direct extraction from 1 g (dry weight equivalent) of soil.
- Follow standard sampling/handling practices (see referenced ISO 18400-206) to preserve microbiological integrity.
- Lysis strategy
- Combined mechanical (bead-beating) and chemical lysis to release DNA from diverse and hard-to-lyse microbes.
- Mechanical lysis duration increased in this edition to improve yield.
- Bead composition and quantities
- Specific bead types and amounts are defined to optimise cell disruption across taxa (changes from the previous edition noted).
- Chemical processing
- Thermal incubation (e.g., 70 °C for 30 min) for chemical lysis.
- Potassium acetate used to precipitate proteins.
- DNA precipitation with ice‑cold isopropanol, wash with 70% ethanol, and final resuspension in sterile water or TE buffer.
- Quality control and quantification
- DNA integrity assessed by agarose gel electrophoresis.
- DNA quantity measured with a fluorometer.
- Validation, storage and reporting
- Procedures for validating extraction performance, storing nucleic acids, and preparing a compliant test report are specified.
Applications and users
- Practical applications
- Microbial community profiling (α- and β-diversity), ecological and agronomic soil health monitoring, impact assessment, and research involving soil microbiomes.
- Supports qPCR, amplicon-based NGS workflows and other molecular assays used for soil monitoring, biodiversity studies and environmental diagnostics.
- Who should use it
- Soil scientists, environmental microbiologists, contract testing laboratories, agricultural and forestry researchers, environmental consultants, and regulatory agencies implementing routine soil microbial monitoring.
Related standards
- ISO 18400-206: Sampling, handling and storage of soil for microbiological assessment (normative reference).
- EN ISO 11063:2020 supersedes EN ISO 11063:2013 - consult Annex A of the standard for detailed differences.
Keywords: EN ISO 11063:2020, soil DNA extraction, soil quality, direct extraction of soil DNA, qPCR, next-generation sequencing, microbial community, soil monitoring.