The Harmonized World Soil Database version 2.0 (HWSD v2.0) is developed by FAO and IIASA as a unique global soil inventory providing information on the morphological, chemical and physical properties of soils at approximately 1 km resolution. Its main objective is to serve as a basis for prospective studies on agro-ecological zoning, food security and climate change.
This updated version (HWSD v2.0) is built on the previous versions of HWSD with several improvements on (i) the data source that now includes several national soil databases, (ii) an enhanced number of soil attributes available for seven soil depth layers, instead of two in HWSD v1.2, and (iii) a common soil reference for all soil units (FAO1990 and the World Reference Base for Soil Resources). This contributes to a further harmonization of the database.
Data publication: 2023-01-27
Citation:
FAO & IIASA. 2023. Harmonized World Soil Database version 2.0. Rome and Laxenburg. https://doi.org/10.4060/cc3823en
Contact points:
Responsible Party: FAO-UN
Resource Contact: Matieu Henry
Metadata Contact: GAEZ
Data lineage:
HWSD v2.0 was built on the previous version, but with several improvements:
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The replacement of soil data derived from the ISRIC - WISE database with soil data of the WISE30sec database (Batjes, 2015) more than doubled the number of soil profiles used from 10 250 to 21 000. This database uses a climatic co-variant based on the Kӧppen-Geiger climatic classification replacing the topsoil texture variant used in the original HWSD.
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In the HWSD v1.2 soil attribute data were limited to two layers, topsoil (0–30 cm) and subsoil (30–100 cm). HWSD v2.0 uses seven depth layers as available from WISE30sec, namely 0–20 cm, 20–40 cm, 40–60 cm, 60–80 cm, 80–100 cm, 100–150 cm and 150–200 cm. The 2-layer approach has been considered a limitation for some modelling needs and is herewith corrected.
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Soil attribute information could be expanded with additional attribute data available from WISE30sec namely: effective CEC, total nitrogen, nitrogen over carbon ratio (C/N) and aluminum saturation.
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The incorporation of national soil databases from Afghanistan, Ghana and Türkiye improved detail through expanding the number of soil mapping units from 16 327 In HWSD v1.2 to 29 538 in HWSD v2.0. The inclusion of the three national harmonized data bases for Afghanistan, Ghana and Türkiye produced as spin-off development of standards for incorporation of national data in HWSD v2.0.
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HWSD v2.0 uses the FAO 1990 Revised Legend for all soil units and a correlation of all soil units with the latest version of the World Reference Base for Soil Resources (IUSS Working Group WRB, 2022), contributing to further harmonization of the database.
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An up-to-date land cover layer was prepared to better identify built-up areas (Fischer, et al., unpublished). This layer was used for identifying Urbic Anthrosols (FAO and ISRIC, 1990) and Technosols (IUSS Working Group WRB, 2022).
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A number of soil parameters have been made more specific: (a) reference soil depth has been replaced by rootable soil depth and the available water capacity (AWC) has been recalculated accounting for rootable soil depth, mineralogy, granulometry and salinity (b) the USDA textural class and the Reference Bulk Density have been included for the seven depth layers.
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Full use has been made of soil phase information globally available in the Digital Soil Map of the World. It was accounted for defining WRB Soil Reference Groups and Soil Units.
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The HWSD viewer was enhanced for dealing with the expanded information in HWSD v2.0.
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The 1 km (30 arc-second) resolution has been maintained, in line with the scale of the majority of the source material.
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Error estimates and statistics (mean, standard deviation (SD) and standard error (SE); median and median of absolute deviation (MAD); upper and lower quartiles as well as 10 percent percentiles (where n > 10); and minimum and maximum recorded for the given sample population.) of individual soil parameters are accessible through the WISE30sec database (Batjes, 2015, 2016).
Resource constraints:
All rights reserved. No part of this Harmonized World Soil Database may be reproduced, stored in a retrieval system or transmitted by any means for resale or other commercial purposes without written permission of the copyright holders. Reproduction and dissemination of material in this information product for educational or other noncommercial purposes are authorized without any prior written permission from the copyright holders provided the source is fully acknowledged.
Online resources:
