Spectral reflectance features with varied soil properties during drying process

Spectral water absorption reflectance features of soils are examined with respect to their relationship to soil water content. Three soil samples, selected to represent a variety of soil properties, were monitored as the samples progressed from fully saturated to air dry. Two water absorption band features in SWIR were observed and selected as metric to relate water content changes. Counterintuitively, band depth did not decrease monotonically during the whole drying process. Although the change in water absorption band depths with water content varied with the soil type, all curves could be represented by several linear segments that related to similar drying states independent of soil properties.