Soil Data Derived from WISE for Use in Global and Regional AEZ Studies (Version 1.0)

During discussions at the International Institute for Applied Systems Analysis (IIASA), the need was identified for refinement of the agro-edaphic element in the revision of FAO's \f2Agro-Ecological Zones\f1 AEZ methodology carried out by IIASA and FAO and in the IIASA's \f2Modeling Land Use and Land Cover Change in Europe and Northern Eurasia\f1 (LUC) project. To this avail, the 4350 soil profile descriptions held in ISRIC's World Inventory of Soil Emission Potential (WISE) database were stratified by soil unit, topsoil textural class and depth zone (0-30 cm and 30-100 cm). Upon a screening on analytical methods used and application of an outlier rejection scheme, derived statistics were generated for 30 soil chemical and physical attributes identified as being important for AEZ studies and analyses of global environmental change. Selected results for Acrisols, classified according to the 1974 version of FAO-Unesco Soil Map of the World Legend, are presented as examples in the Appendices. Special attention was paid to the assessment of Total Available Water Capacity (TAWC), an important parameter in calculation of the length of growing period. Data have been compiled for all the considered combinations of soil unit, topsoil textural class, attribute and depth zone, both for the 1974 and 1990 Legend. Simple taxotranfer rules are introduced to fill some of the gaps that remained in the derived data, notably where sufficient measured data were lacking for particular attributes. As a sequel to the current study, the taxotransfer rules should be fine-tuned and the results should be supplemented with data extracted from the FAO's CD-ROM of the \f2Digital Soil Map of the World and Derived Soil Properties\f1. This combined database will be revised by a group of soil experts. The recommended level-of-detail for presenting the various results should also be determined at that stage. This follow-up activity is necessary to arrive at a mutually agreed upon set of derived soil properties for land evaluation and environmental studies at the continental and global level, for subsequent release as a unified product to the global modeling community.