Vis-NIR Soil Spectral Library of the Hungarian Soil Degradation Observation System

Since soil spectroscopy is considered to be a fast, simple, accurate and non-destructive analytical method, its application can be integrated with wet analysis as an alternative. Therefore, development of national-level soil spectral libraries containing information about all soil types represented in a country is continuously increasing to serve as a basis for calibrated predictive models capable of assessing physical and chemical parameters of soils at multiple spatial scales. In this article, we present a database containing laboratory and visible-near infrared spectral data of legacy soil samples from the Hungarian Soil Degradation Observation System (HSDOS). The published data set includes the following parameters measured in 5,490 soil samples: pHKCl, plasticity index according to Hungarian standard (PLI), soil organic matter (SOM), calcium carbonate (CaCO3), total salt content (TSC), total nitrogen (Ntotal), soluble phosphorus (P2O5-AL), soluble potassium (K2O-AL), soil profile depth and reflectance data between 350 and 2,500 nm wavelength. The presented database can be a complement for further soil related research on continental, national or regional scales to support sustainable soil management. Uploaded CSV file contains variables for general information, soil parameters and reflectance data of spectral bands between 350-2,500 nm. Details about variables can be found in Table 1. Column name Description Method Unit SAMPLE_TDR_ID Original TDR IDs - - SAMPLING_DATE Date of sampling - YYYY-MM-DD NORTHING_EOV Northing coordinate of sampling area centroids - m EASTING_EOV Easting coordinate of sampling area centroids - m LON_WGS84 Longitude of sampling area centroids - ° LAT_WGS84 Latitude of sampling area centroids - ° pH_KCl pH Potentiometer (MSZ–08 0206-2: 1978)40 - PLI Plasticity index according to Hungarian standard Yarn test of Arany (MSZ–08 0205-2:1978)41 - SOM Soil organic matter E4/E6 ratio42,43 (MSZ–08-0452:1980)44 % CaCO3 Calcium carbonate Scheibler type calcimeter (MSZ–08 0206-2:1978)40 % TSC Total salt content EC-TDS electrode (MSZ–08-0206-2:1978)40 % TN Total nitrogen Kjeldahl method45 (ISO 11261:1995)46 mg kg-1 P2O5_AL Soluble phosphorus AL extract atomic adsorption spectrophotometry (MSZ 20135:1999)47 mg kg-1 K2O_AL Soluble potassium AL extract, flame photometer (MSZ 20135:1999)47 mg kg-1 PROFILE_LEVEL Soil profile depth level - - SPC350:2500 spectral reflectance in the range of 350 and 2500 nm ASD FieldSpec 4 spectroradiometer - Table