ISDA is proud to release a large dataset of analysed soil samples covering the African continent. These data are analysis-ready and do not require any preprocessing before usage. The dataset was collected and analysed according to protocols created by the African Soil Information Service (AfSIS) project (Vågen T-G et al., 2010). AfSIS was an initiative funded by the Bill and Melinda Gates Foundation, aimed at improving soil information across Africa. Data were collected and analysed between 2008 and 2020. In total, over 50,000 soil samples were collected across more than 15 countries.
How were the data collected and analysed?
At each location, soil was collected at 2 depths - the 0-20cm horizon (topsoil) and the 20-50cm horizon (subsoil). Samples were then sent to the lab for analysis. Roughly 10% of the samples were analysed by wet chemistry analysis, with the other 90% being measured by mid-infrared diffuse reflectance spectroscopy (dry chemistry).
The 10% of data analysed by wet chemistry were used as a training set. These data were used to train spectral models that predict soil properties from the other 90% of samples that were analysed by infrared spectroscopy. For some soil properties there are no spectral predictions because the produced models did not reach an acceptable level of accuracy. Some properties might also be missing from analysis as properties were analysed over a long period of time.
How can I access the data?
This is the first contribution to what we hope will be an ever-growing open soil analysis dataset for the African continent. We will add additional datasets as they become available. If you’d like to contribute soil data, please get in touch, or open a pull request to our GitHub repository.
We use this open dataset as an input to iSDAsoil. We plan to continuously update iSDAsoil when new soil data becomes available.
Citing this dataset
This dataset is available under a CC-BY-4.0 licence. Please cite using the following DOI: https://doi.org/10.17605/OSF.IO/A69R5.
This release represents the result of a huge amount of work by a great number of individuals and organizations, including iSDA. These include:
- Alliance Biodiversity and CIAT
- The Earth Institute of Columbia University
- ISRIC - World Soil Information
- Rothamsted Research
Subsets of the AfSIS data included in this dataset have previously been released. Links to those datasets can be found here: Nigeria AfSIS phase II (NiSIS), Ghana AfSIS phase II (GhaSIS), Tanzania AfSIS phase II, AfSIS phase I wet chemistry, AfSIS phase I mid-infrared spectra.
If you have any further questions about this data release, please get in touch at email@example.com.