DIN EN ISO 11274:2014-07

This International Standard specifies laboratory methods for determination of the soil water-retention characteristic. This International Standard 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: a) A method which uses sand, kaolin or ceramic suction tables for the determination of matric pressures from 0 kPa to -50 kPa. b) A method which uses a porous plate and burette apparatus for the determination of matric pressures from 0 kPa to -20 kPa. c) A method which uses a pressurized gas and a pressure plate extractor for the determination of matric pressures from -5 kPa to -1 500 kPa. d) A method which uses 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. Examples of how the results obtained by means of these methods can be used are: a) to enable evaluation of the pore size distribution (for example identification of macro- and micropores); b) to determine an index for the plant-available water in the soil and to classify the soil accordingly (for example for irrigation purposes); c) to determine the drainable pore space (for example for drainage design, pollution risk assessments); d) to monitor changes in the structure of a soil (caused by, for example, tillage, compaction or addition of organic matter or synthetic soil conditioners); e) to ascertain the relationship between the negative matric pressure and other soil physical properties (for example hydraulic conductivity, thermal conductivity); f) to determine water content at specific negative matric pressures (for example for microbiological degradation studies); g) to estimate other soil physical properties (for example hydraulic conductivity). This International Standard has been prepared by Technical Committee ISO/TC 190 "Soil quality" and has been taken over by Technical Committee CEN/TC 345 "Characterization of soils" without any modification. The responsible German body is Subcommittee NA 119-0-02-02 UA "Chemische und physikalische Verfahren" ("Chemical and physical processes") of Working Committee NA 119-01-02 AA "Abfall- und Bodenuntersuchung" ("Examination of waste and soil") at the Water Practice Standards Committee (NAW).