Overview
EN ISO 11260:2018 - published by CEN as the European adoption of ISO 11260:2018 - specifies a laboratory method to determine the effective cation exchange capacity (CEC) of soils at the soil’s native pH and to quantify exchangeable sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg). The procedure uses a barium chloride (BaCl2) solution to displace exchangeable cations and measures excess magnesium after precipitation of barium as barium sulfate. It applies to all types of air‑dried soil samples and recommends ISO 11464 for pre‑treatment.
Key topics and technical requirements
- Principle: Saturate soil with 0.1 mol·L‑1 BaCl2, equilibrate with 0.01 mol·L‑1 BaCl2, then add excess 0.02 mol·L‑1 MgSO4. Precipitation of Ba as BaSO4 frees exchange sites for Mg; excess Mg is measured to calculate CEC.
- Analytical measurement: Excess magnesium is determined by ICP‑AES (inductively coupled plasma atomic emission spectrometry); alternative methods with comparable precision/detection limits are permitted.
- Exchangeable cations: Concentrations of Na, K, Ca and Mg (and potentially Fe, Mn, Al) can be measured in the 0.1 mol·L‑1 BaCl2 extract.
- Applicability: Valid for all air‑dried soils; pre‑treatment per ISO 11464 is applicable.
- Interferences and notes:
- Soluble salts, calcite or gypsum can interfere with results.
- Dissolved organic matter (yellowish‑brown extracts) should be recorded - it contributes to measured CEC and may cause underestimation of the soil’s actual CEC.
- The sum of exchangeable cations may exceed CEC if salts dissolve during extraction.
- Quality control: The standard includes requirements for calibration checks, repeatability and reproducibility, and details for test reporting.
Applications and who uses it
- Used by soil testing laboratories, environmental‑characterization labs, agronomy and land management consultants, and researchers for:
- Assessing soil fertility and nutrient holding capacity.
- Determining base saturation levels for agronomic or environmental evaluation.
- Supporting soil classification, remediation monitoring and research into soil chemistry.
- Useful where standardized, comparable CEC and exchangeable cation data are required for regulatory, scientific or commercial decisions.
Related standards
- ISO 11464 - Soil sample pre‑treatment (recommended).
- ISO 3696 - Water for analytical laboratory use (reagents).
- ISO 11265 - Determination of specific electrical conductivity (referenced for context).
Keywords: EN ISO 11260:2018, soil quality, cation exchange capacity, CEC, barium chloride, exchangeable sodium potassium calcium magnesium, ICP‑AES, soil testing, base saturation.