Use of reflectance spectroscopy for estimating the soil properties.

In this study, the soil physical properties (SPPs; clay and sand con-tents, oven-dry soil bulk density, and organic carbon content) were estimated using soil reflectance measurements in the visible, near-infrared, and shortwave infrared (Vis-NIR-SWIR) range (350–2,500 nm), in a sub-catchment located near the village of Monteforte Cilento in the Alento hydrological observatory. The soil samples were collected from the topsoil over 63 positions. Partial Least Squares Regression (PLSR) was used as a multivariate calibration technique, resulting in root mean square error (RMSE) values of 8.63% for sand, 6.59% for clay, 0.43% for organic carbon, and 0.10 g cm−3 for the soil bulk density on the validation data set. The SPPs represent the primary input variables in the pedotransfer functions (PTFs), which estimate the soil hydraulic properties when working at relatively large scales. This additional step will be implemented in a follow-up study.