World globes, image by NASA/JPL/NIMA

A Global Spectral Library to Characterize the World’s Soil

By Dr. Sabine Grunwald

Working with a global team of researchers, we synthesized a spectral dataset and measured soil data to model various critical soil indicators at a global scale. The study focused on modeling of various soil attributes, such as soil organic and inorganic carbon, clay, silt, sand and iron contents, cation exchange capacity, and pH, using a global soil spectral (visible/near-infrared) library. We used big data analysis to develop global soil maps/models for those soil properties, demonstrating the impact and mitigation potential under various change stressors, including global climate change and land use change.

Fig. 3 of Viscarra Rossel et al. 2016: Locations of the 12,509 unique sites with reflectance spectra that are in the global database.

It is currently the largest and most diverse soil database of its kind. The information encoded in the spectra can describe soil composition and be associated to land cover and its global geographic distribution, which acts as a surrogate for global climate variability. Global soil data allows addressing the profound unprecedented pressures on soils including degradation in quality, urbanization, soil loss, and more that impact soil, food and human security.

The study is presented in Earth Science Reviews:

Viscarra Rossel, R.A., Behrens, T., Ben-Dor, E., Brown, D.J., Demattê, J.A.M., Shepherd, K.D., Shi, Z., Stenberg, B., Stevens, A., Adamchuk, V., Aïchi, H., Barthès, B.G., Bartholomeus, H.M., Bayer, A.D., Bernoux, M., Böttcher, K., Brodský, L., Du, C.W., Chappell, A., Fouad, Y., Genot, V., Gomez, C., Grunwald, S., Gubler, A., Guerrero, C., Hedley, C.B., Knadel, M., Morrás, H.J.M., Nocita, M., Ramirez-Lopez, L., Roudier, P., Campos, E.M.R., Sanborn, P., Sellitto, V.M., Sudduth, K.A., Rawlins, B.G., Walter, C., Winowiecki, L.A., Hong, S.Y., Ji, W., 2016. A global spectral library to characterize the world’s soil. Earth-Science Reviews 155, 198–230.

For more information on work being done in the Pedometrics, Landscape Analysis & GIS Laboratory, see