Acknowledgements

The data used in this manual came from various sources. The Government of Sudan through the Agriculture Research Centre (ARC) in Wad Madani, authorized the use of their soil data and some covariates. Remote sensing images and elevation data were downloaded from the United States Geological Survey website (https://earthexplorer.usgs.gov/). We received technical and financial support from Food Agriculture Organization (FAO) through Global Soil Partnership (GSP).