Harmonized World Soil Database - HWSD (version 1.2)

HWSD-coverDuring discussions at the International Institute for Applied Systems Analysis (IIASA) in 1996, the need was identified for refinement of the agro-edaphic element of IIASA and FAO's Agro-Ecological Zones (AEZ) methodology then being used for IIASA?s "Modeling Land Use and Land Cover Change in Europe and Northern Eurasia (LUC)" project. An IIASA Interim Report was produced in 1997 detailing twenty soil attributes identified as being important for land evaluation, the analyses performed on existing databases, and methodologies for the development of taxotransfer rules to derive necessary data. Conclusions of this report were used for the analyses of that time, but the process that was born continued to develop into what would eventually become a separate product, the Harmonized World Soil Database. Between 2003 and 2006, IIASA and FAO sought out additional partners, including: - ISRIC-World Soil Information, together with FAO, were responsible for the development of regional soil and terrain databases and the WISE soil profile database; - the European Soil Bureau Network, which had recently completed a major update of soil information for Europe and northern Eurasia, and - the Institute of Soil Science, Chinese Academy of Sciences, which provided the recent 1:1,000,000 scale Soil Map of China. Vast volumes of recently collected regional and national updates of soil information collected by the partners were assimilated and harmonized by IIASA, where the HWSD raster, database, and viewer software were designed, implemented, and packaged for CD and web distribution into this state-of-the-art database. Version 1.0 was released in 2008. Since then, it has been updated with new information several times, has been used extensively around the world, and has recently been adopted by the Global Soil Partnership (GSP) as the definitive soil database at present, with plans for further updates made as part of the GSP process. The HWSD is of immediate use in the context of the Climate Change Convention and the Kyoto Protocol for soil carbon measurements and for the FAO/IIASA Global Agro-ecological Assessment studies (GAEZ 2012), for which HWSD was developed in the first place. The HWSD contributes sound scientific knowledge for planning sustainable expansion of agricultural production to achieve food security and provides information for national and international policymakers in addressing emerging problems of land competition for food production, bio-energy demand and threats to biodiversity. The HWSD is a 30 arc-second raster database with over 16000 different soil mapping units that combines existing regional and national updates of soil information worldwide (SOTER, ESD, Soil Map of China, WISE) with the information contained within the 1:5 000 000 scale FAO-UNESCO Soil Map of the World (FAO, 19711981). The resulting raster database consists of 21600 rows and 43200 columns, which are linked to harmonized soil property data. The use of a standardized structure allows for the linkage of the attribute data with the raster map to display or query the composition in terms of soil units and the characterization of selected soil parameters (organic Carbon, pH, water storage capacity, soil depth, cation exchange capacity of the soil and the clay fraction, total exchangeable nutrients, lime and gypsum contents, sodium exchange percentage, salinity, textural class and granulometry). Reliability of the information contained in the database is variable: the parts of the database that still make use of the Soil Map of the World such as North America, Australia, West Africa and South Asia are considered less reliable, while most of the areas covered by SOTER databases are considered to have the highest reliability (Central and Southern Africa, Latin America and the Caribbean, Central and Eastern Europe)