X to Y mm fraction of the fine earth fraction*; Y as specified in the analytical method description (e.g. Y = 0.05 mm) (g/100g).

ISRIC is developing a centralized and user–focused server database, known as ISRIC World Soil Information Service (WoSIS). The aims are to:

• Safeguard world soil data "as is"

• Share soil point (i.e. profile) data upon their standardization, and ultimately harmonization

• Provide quality-assessed, geo-referenced soil data for a growing range of environmental applications (e.g. SoilGrids250m).

At present, wosis_latest contains standardized data for 217,000 profiles. The number of measured data for each property varies between profiles and with depth, generally depending on the purpose of the initial studies. Further, in most source data sets, there are fewer data for soil physical as opposed to soil chemical attributes and there are fewer measurements for deeper than for superficial horizons. Generally, limited quality information is associated with the various source data.

Further information is provided in a https://doi.org/10.5194/essd-12-299-2020 and https://www.isric.org/sites/default/files/WOSISprocedureManual_2020nov17web.pdf.

* The fine earth fraction is generally defined as being less than 2 mm. However, an upper limit of 1 mm was used in the former Soviet Union and its sattelite states (Katchynsky scheme). This has been indicated in the database.