Thanks to the initiative of Jonas, Christoph and Sam the ISIMIP3 protocol now provides an additional soil data set that meets criteria specific to the Agriculture Sector. The data are based on HWSD soil data and were aggregated to the ISIMIP 0.5° grid. The aggregation has been performed using the dominant soil class on cropland (using the 5 arc-minute MIRCA2000 cropland data) per 0.5 degree pixel. The script can be easily adjusted to process data without the cropland weighting, so that it could be used for other sectors, too. Please get in touch and align with sector coordination in case this is wanted.
For further details please refer to the README in the ISIMIP3a/InputData/geo_conditions/soil/ folder.