WISE derived soil properties on a 0.5 by 0.5 degree global grid, version 3.0

Version 1.2 of describes a harmonized dataset of derived soil properties for the world. It was created using the soil distribution shown on the 1:5 million scale FAO-Unesco Soil Map of the World (DSMW), rasterised at 5 by 5 arcminutes, and soil property estimates derived from the ISRIC-WISE soil profile database, version 3.1. The dataset considers 19 soil variables that are commonly required for agro-ecological zoning, land evaluation, crop growth simulation, modelling of soil gaseous emissions, and analyses of global environmental change. It presents ‘best’ estimates for: soil drainage class, organic carbon content, total nitrogen, C/N ratio, pH (H2O), CECsoil, CECclay, effective CEC, base saturation, aluminium saturation, calcium carbonate content, gypsum content, exchangeable sodium percentage (ESP), electrical conductivity, particle size distribution (i.e. content of sand, silt and clay), content of coarse fragments (less than 2 mm), bulk density, and available water capacity (-33 to -1500 kPa). These estimates are presented by FAO soil unit for fixed depth intervals of 20 cm up to 100 cm depth (or less when appropriate) for so-called virtual profiles. The associated soil property values were derived from analyses of some 10,250 profiles held in WISE using a scheme of taxonomy-based taxotransfer rules complemented with expert-rules. The type of rules used to derive the various soil property values have been flagged in the database to provide an indication of the possible confidence in the derived data. Most map units on the DSMW are complex, comprising up to eight different soil units. Assessments and model applications that use the derived soil properties therefore should consider the full map unit composition and depth range. The soil property values presented here should be seen as best estimates based on the current selection of soil profiles in WISE, the procedure for clustering the measured data, taxotransfer scheme used for deriving soil, properties, and the spatial data of the digital Soil Map of the World. The derived information may be used for exploratory assessments at a broad scale (greater than 1:5 million; 5 by 5 arcminutes and coarser), pending the global update of the information on world soil resources at more detailed scales, upon due consideration of the underlying generalisations and assumptions. Note: A more recent assessment, at a resolution of 30arcsec (WISE30sec), is available at: http://data.isric.org/geonetwork/srv/eng/catalog.search#/metadata/dc7b283a-8f19-45e1-aaed-e9bd515119bc

This harmonized dataset of derived soil properties for the world (WISE30sec) is comprised of a soil-geographical and a soil attribute component. The GIS dataset was created using the soil map unit delineations of the broad scale Harmonised World Soil Database, version 1.21, with minor corrections, overlaid by a climate zones map (Köppen-Geiger) as co-variate, and soil property estimates derived from analyses of the ISRIC-WISE soil profile database for the respective mapped ‘soil/climate’ combinations. The dataset considers 20 soil properties that are commonly required for global agro-ecological zoning, land evaluation, crop growth simulation, modelling of soil gaseous emissions, and analyses of global environmental change. It presents ‘best’ estimates for: organic carbon content, total nitrogen, C/N ratio, pH(H2O), CECsoil, CECclay, effective CEC, total exchangeable bases (TEB), base saturation, aluminium saturation, calcium carbonate content, gypsum content, exchangeable sodium percentage (ESP), electrical conductivity, particle size distribution (content of sand, silt and clay), proportion of coarse fragments (less than 2 mm), bulk density, and available water capacity (-33 to -1500 kPa); also the dominant soil drainage class. Soil property estimates are presented for fixed depth intervals of 20 cm up to a depth of 100 cm, respectively of 50 cm between 100 cm to 200 cm (or less when appropriate) for so-called ‘synthetic’ profiles’ (as defined by their ‘soil/climate’ class). The respective soil property estimates were derived from statistical analyses of data for some 21,000 soil profiles managed in a working copy of the ISRIC-WISE database; this was done using an elaborate scheme of taxonomy-based transfer rules complemented with expert-rules that consider the ‘in-pedon’ consistency of the predictions. The type of rules used was flagged to provide an indication of the possible confidence (i.e. lineage) in the derived data. Best estimates for each attribute are given as means and standard deviations (STD), as calculated for the sample populations that remained upon application of a robust data outlier detection scheme. Results of the analyses can be linked to the spatial data through the unique map unit (grid cell) identifier, which is a combination of the soil unit and climate class code. Most map units are comprised of up to ten different components; each of these with their own range of derived soil properties and associated statistical uncertainties. Estimates of global soil organic carbon (SOC) stocks to 200 cm are presented in the technical documentation as an example of possible application. For citation use: Batjes NH 2016. Harmonised soil property values for broad-scale modelling (WISE30sec) with estimates of global soil carbon stocks. Geoderma 2016(269), 61-68 ( http://dx.doi.org/10.1016/j.geoderma.2016.01.034 ) Note: The chemical and physical soil property estimates generated for WISE30sec have been used to populate version 2.0 of the Harmonised World Soil Database (see https://data.isric.org/geonetwork/srv/eng/catalog.search#/metadata/54aebf11-ec73-4ff8-bf6c-ecff4b0725ea).

Version 3.1 of the ISRIC-WISE database (WISE3) was compiled from a wide range of soil profile data collected by many soil professionals worldwide. All profiles have been harmonized with respect to the original Legend (1974) and Revised Legend (1988) of FAO-Unesco. Thereby, the primary soil data ─ and any secondary data derived from them ─ can be linked using GIS to the spatial units of the digitized Soil Map of the World as well as more recent digital Soil and Terrain (SOTER) databases through the soil legend code. WISE3 holds selected attribute data for some 10,250 soil profiles, with some 47,800 horizons, from 149 countries. Individual profiles have been sampled, described, and analyzed according to methods and standards in use in the originating countries. There is no uniform set of properties for which all profiles have analytical data, generally because only selected measurements were planned during the original surveys. Methods used for laboratory determinations of specific soil properties vary between laboratories and over time; sometimes, results for the same property cannot be compared directly. WISE3 will inevitably include gaps, being a compilation of legacy soil data derived from traditional soil survey, which can be of a taxonomic, geographic, and soil analytical nature. As a result, the amount of data available for modelling is sometimes much less than expected. Adroit use of the data, however, will permit a wide range of agricultural and environmental applications at a global and continental scale (1:500 000 and broader). Preferred citation: Batjes NH 2009. Harmonized soil profile data for applications at global and continental scales: updates to the WISE database. Soil Use and Management 5:124–127, http://dx.doi.org/10.1111/j.1475-2743.2009.00202.x

A homogenized, global set of 1,125 soil profiles is presented. These profiles have been extracted from the database developed at ISRIC for a project on "World Inventory of Soil Emission Potentials" (WISE), as a contribution to the activities of the Global Soils Data Task Group of IGBP-DIS. The subset consists of a selection of 665 profiles originating from digital data files released by the Natural Resources Conservation Service (NRCS, Lincoln), 250 profiles obtained from the Food and Agriculture Organization (FAO, Rome), and 210 profiles from the reference collection of the International Soil Reference and Information Centre (ISRIC, Wageningen). All profiles are georeferenced and classified in the FAO-Unesco Legend whereby they can be linked to the edited and digital version of the FAO-Unesco Soil Map of the World. This data set is being released in the public domain for use by global modellers and other interested scientists. It is envisaged that the data set will be expanded by ISRIC when new, uniform soil profile data become available. Note: a) A more recent version (some 10,000 profiles) of WISE profiles is available at: http://data.isric.org/geonetwork/srv/eng/catalog.search#/metadata/a351682c-330a-4995-a5a1-57ad160e621c (2009) b) For a larger compilation see the WoSIS database: http://isric.org/explore/wosis (2017)

This harmonized set of soil parameter estimates for Latin America and the Caribbean was derived from a revised version of the 1:5M Soil and Terrain Database for the region (SOTERLAC, ver. 2.0) and the ISRIC-WISE soil profile database. The land surface of Latin America and the Caribbean has been characterized using 1585 unique SOTER units, corresponding with 5855 polygons. The major soils have been described using 1660 profiles, selected by national soil experts as being representative for these units. The associated soil analytical data have been derived from soil survey reports. These sources seldom hold all the physical and chemical attributes ideally required by SOTER. Gaps in the measured soil profile data have been filled using a step-wise procedure that uses taxotransfer rules, based on about 9600 soil profiles held in the WISE database, complemented with expert-rules. Parameter estimates are presented by soil unit for fixed depth intervals of 0.2 m to 1 m depth for: organic carbon, total nitrogen, pH(H2O), CECsoil, CECclay, base saturation, effective CEC, aluminium saturation, CaCO3 content, gypsum content, exchangeable sodium percentage (ESP), electrical conductivity of saturated paste (ECe), bulk density, content of sand, silt and clay, content of coarse fragments (less than 2 mm), and available water capacity (-33 to -1500 kPa). These attributes have been identified as being useful for agro-ecological zoning, land evaluation, crop growth simulation, modelling of soil carbon stocks and change, and analyses of global environmental change. The current parameter estimates should be seen as best estimates based on the current selection of soil profiles and data clustering procedure. Taxotransfer rules have been flagged to provide an indication of the possible confidence in the derived data. Results are presented as summary files and can be linked to the 1:5M scale SOTERLAC map in a GIS, through the unique SOTER-unit code. The secondary data set is considered appropriate for studies at the continental scale (greater than 1:5M). Correlation of soil analytical data should be done more rigorously when more detailed scientific work is considered.

This harmonized set of soil parameter estimates for Southern Africa has been derived from the 1:2M scale Soil and Terrain Database for Southern Africa (SOTERSAF ver. 1.0) and ISRIC-WISE soil profile database. The land surface of Southern Africa has been characterized using 4022 unique SOTER units, corresponding with 6099 polygons. The major soils have been described using 941 profiles, selected by national soil experts as being representative for these units. The associated soil analytical data have been derived from soil survey reports. These sources seldom hold all the physical and chemical attributes ideally required by SOTER. Gaps in the measured soil profile data have been filled using a step-wise procedure that uses taxonomy-based pedotransfer rules, based on some 9600 soil profiles held in the WISE2 database. Parameter estimates are presented by soil unit for fixed depth intervals of 0.2 m to 1 m depth for: organic carbon, total nitrogen, pH(H2O), CECsoil, CECclay, base saturation, effective CEC, aluminium saturation, CaCO3 content, gypsum content, exchangeable sodium percentage (ESP), electrical conductivity of saturated paste (ECe), bulk density, content of sand, silt and clay, content of coarse fragments (less than 2 mm), and available water capacity (-33 to -1500 kPa). These attributes have been identified as being useful for agro-ecological zoning, land evaluation, crop growth simulation, modelling of soil carbon stocks and change, and analyses of global environmental change. The current parameter estimates should be seen as best estimates based on the current selection of soil profiles and data clustering procedure. Taxotransfer rules have been flagged to provide an indication of the possible confidence in the derived data. Results are presented as summary files and have been linked to the 1:2M scale SOTERSAF map in a GIS, through the unique SOTER-unit code.