DIN EN ISO 23753-2:2011-09

This International Standard specifies a method for determining soil dehydrogenase activity using 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride (INT). This standard is not applicable for determining the dehydrogenase activity in upper layers (L, F, H horizons) of forest humus forms with low microbial activity (for example, mor), or in soils showing reducing properties (for example, waterlogged soils). The soil microflora is responsible for the decomposition and conversion of organic substances, aggregation stability and the carbon, nitrogen, sulfur and phosphorus cycles. Dehydrogenases, as respiratory chain enzymes, play a major role in the energy production by organisms. They oxidize organic compounds by transferring two hydrogen atoms. Dehydrogenases are essential components of the enzyme system of all microorganisms. Dehydrogenase activity can therefore be used as an indicator of biological redox systems and as a measure of microbial activity in the soil. The text of ISO 23753-2:2005 has been prepared by Technical Committee ISO/TC 190 "Soil quality" of the International Organization of standardization (ISO) and has been adopted as EN ISO 23753-2:2011 by CEN/TC 345 "Characterization of soils", the secretariat of which is held by NEN. The text of ISO 23753-2:2005 has been approved by CEN as EN ISO 23753-2:2011 without any alterations. The Committee responsible for this standard is NA 119-01-02-04 UA "Biologische Verfahren" ("Biological Methods") at DIN.