Conduction is the primary mode of heat transfer in soil.
Radiative heating is affected by the amount of radiation reflected or absorbed.
Water was poured on the sand on left side of the container. You can observe the darker color in the picture. Wet soils are darker than dry soils. After about 30 minutes, the dry soil temperature had increased about 10 o Celsius, while the wet soil temperature had increased about 1 o Celsius. 1 o than the soil temperature.