IGBP-DIS soil data set for pedotransfer function development

At the request of the Global Soil Data Task (GSDT) of the Data and Information System of the International Geosphere Biosphere Programme (IGBP-DIS), ISRIC prepared a uniform soil data set for the development of pedotransfer functions. The necessary chemical and physical soil data have been derived from ISRIC's Soil Information System (ISIS) and the CD-ROM of the Natural Resources Conservation Service (USDA-NRCS). All soil samples were clustered into functional groups based on soil textural class and (calculated) activity of the clay minerals (9 classes), while samples from organic soils and allophanic soils were flagged. The digital set contains data for 131,472 samples, originating from 20,920 profiles. It is presented as a comma delimited ASCIIfile and in dBASE IV format. GSDT will use the data set to develop a number of pedotransfer functions for often required, yet seldom measured soil properties. Interaction with the global soil and modelling community led to the identification of four soil properties as being especially important and urgently needed: soil organic carbon, soil total nitrogen, water holding capacity, and soil thermal properties.