Effect of salty crust on soil albedo

The relationships among soil salt content, soil water content, and soil albedo were investigated for two soils, Masa sandy loam and Kanto loam. Albedos of each soil were measured for various combinations of surface water content and mass of accumulated salt near or on the soil surface. Apparent albedos from soil slab samples were first normalized to apparent albedos at a reference solar zenith angle of 50°, and then corrected to real albedos expected for large-area surfaces by using predetermined linear calibration equations. Under our experimental conditions, we found that the increase of albedo from nonsaline condition reached a value as high as 0.3 with increasing mass of accumulated salt. We present an empirical equation that describes the dependence of albedo on both surface water content and mass of accumulated salt (Γ) above a certain depth. Despite the scatter of the data, a practical result of our experiment is that a unit mass of accumulated salt (mg/cm2) above the depth of 20 mm would increase the albedo approximately by 0.002.