Why is the reflectivity of grassland smaller than that of sand?

The reason is that the grassland is dark, and the rough canopy causes multiple reflections, which increases the absorption and transmission of solar radiation in the grassland.

Influenced by latitude position, land and sea position, weather conditions, length of day and night, topography and other factors, solar radiation is unevenly distributed on the surface. The reflectivity of different properties of the ground is different, with the reflectivity of new snow being the largest, followed by ice, followed by sand, light-colored soil, grassland and cultivated land, and the reflectivity of ocean being the lowest.