A soil property and spectral near- and mid-infrared dataset from cultivated fields sampled in winter 2020, Western Highveld, South Africa.

This data article describes a soil dataset of 790 topsoil samples collected from commercial, cultivated grain-producing fields managed by NWK Ltd. And GWK Ltd. in the Western Highveld region, South Africa. Samples were composite topsoil drawn from the co-operative's routine fertility advisory submissions during a single 2020 winter sampling season; they therefore represent the soil fertility ranges of actively cultivated fields rather than natural profiles. The dataset is provided in a single .csv file and contains reference data for soil pH (KCl), Phosphorus (P-Bray 1), and exchangeable cations Potassium (K), Calcium (Ca) Magnesium (Mg) and Sodium (Na). For each sample, the dataset includes two corresponding spectra: (1) handheld Near-Infrared (NIR) spectra (approx. 7 407 - 4 003 cm⁻¹) acquired with a NeoSpectra spectrometer, and Mid-Infrared (MIR) spectra (approx. 3997 - 600 cm⁻¹) acquired with a Bruker Alpha II spectrometer. This data is valuable for developing and validating pedometric models, for NIR and MIR instrument comparison and spectral fusion, and for extending soil spectral libraries in the Southern African region. The data are openly available in the Zenodo repository within the "Pedometrics South Africa" community.