Fig. 5. Laboratory-measured (+) and visible near-infrared (VNIR) predicted () clay content for three soil cores: (a) a dark-colored Vertisol, (b) an Alfisol with distinct A, E, and Bt horizons, and (c) a Mollisol with secondary CaCO₃ concentrations in the B horizons. Laboratory measurements were taken to represent a row within a horizon, and VNIR predictions were made every 3 cm.