What is ISO 11274 - Soil water retention determination about?
ISO 11274 discusses soil quality with a focus on determining its water-retention characteristic. ISO 11274 specifies laboratory methods for the determination of the soil water-retention characteristic. ISO 11274 applies only to measurements of the drying or desorption curve.
Four methods are described to cover the complete range of soil water pressures as follows:
- Method using sand, kaolin, or ceramic suction tables for the determination of matric pressures from 0 kPa to −50 kPa
- Method using a porous plate and burette apparatus for determination of matric pressures from 0 kPa to −20 kPa
- Method using a pressurized gas and a pressure plate extractor for determination of matric pressures from −5 kPa to −1 500 kPa
- Method using a pressurized gas and pressure membrane cells for determination of matric pressures from −33 kPa to −1 500 kPa
Guidelines are given to select the most suitable method in a particular case.
Who is ISO 11274 - Soil water retention determination for?
ISO 11274 on soil water retention determination is useful for:
- Ecologists and conservationists
- Soil testing laboratories
- Landowners
- Researchers involved in soil sciences / agricultural researchers
Why should you use ISO 11274- Soil water retention determination?
Soil water content and matric pressure are related to each other and determine the water-retention characteristics of the soil. Soil water which is in equilibrium with free water is at zero matric pressure (or suction) and the soil is saturated. As the soil dries, matric pressure decreases (i.e., becomes more negative), and the largest pores empty of water.
The soil water-retention characteristic is different for each soil type. The shape and position of the curve relative to the axes depend on soil properties such as texture, density, and hysteresis associated with the wetting and drying history. Individual points on the water-retention characteristic are determined for specific purposes mentioned in ISO 11274.
The results obtained using these methods can be used, for example:
- To provide an assessment of the equivalent pore size distribution (e.g., identification of macro, and micropores)
- To determine indices of plant-available water in the soil and to classify soil accordingly (e.g., for irrigation purposes)
- To determine the drainable pore space (e.g., for drainage design, pollution risk assessments)
- To monitor changes in the structure of a soil (caused by e.g., tillage, compaction, or addition of organic matter or synthetic soil conditioners)
- To ascertain the relationship between the negative matric pressure and other soil physical properties (e.g., hydraulic conductivity, thermal conductivity)
- To determine water content at specific negative matric pressures (e.g., for microbiological degradation studies)
- To estimate other soil physical properties (e.g., hydraulic conductivity)