Year of publication
2023
Excerpt
This report describes general principles for standardizing soil properties/observations that are served from WoSIS (World Soil Information Service) as ‘wosis_latest’. Data for nominally similar soil properties, collated from disparate sources, are grouped according to main features of the corresponding analytical methods; that is, the properties are grouped according to ‘operational definitions’. For example, main features for defining soil pH are the sample pretreatment, extractant solution (water or salt solution), and in case of salt solutions the salt concentration (molarity), as well as the soil/solution ratio. A further descriptive element may be the type of instrument used for the actual laboratory measurement.
Currently, the following list of chemical and physical properties is standardized:
a) Chemical properties: organic carbon, total carbon, total carbonate equivalent, total nitrogen, phosphorus (extractable P, total P and P retention), soil pH, cation exchange capacity and electrical conductivity.
b) Physical properties: soil texture (sand, silt, and clay), bulk density, coarse fragments and water retention.
Full data harmonization in a global context, the ultimate objective of WoSIS, will first become feasible once results of extensive proficiency testing programmes become freely available and a common set of ’international’ reference methods has been accepted as the common standard by the international soil community; such would provide the basis for method validation between laboratories with their actual/adjusted method.
Currently, the following list of chemical and physical properties is standardized:
a) Chemical properties: organic carbon, total carbon, total carbonate equivalent, total nitrogen, phosphorus (extractable P, total P and P retention), soil pH, cation exchange capacity and electrical conductivity.
b) Physical properties: soil texture (sand, silt, and clay), bulk density, coarse fragments and water retention.
Full data harmonization in a global context, the ultimate objective of WoSIS, will first become feasible once results of extensive proficiency testing programmes become freely available and a common set of ’international’ reference methods has been accepted as the common standard by the international soil community; such would provide the basis for method validation between laboratories with their actual/adjusted method.