Land heats faster, but both water and air hold on to heat longer, air holds on to heat even longer than water.
Most soils are mostly composed of mineral particles, air, and water.
The specific heat of dry soil is about 0.80 kJ/kg/degree C. However since the specific heat of water is very high (4.2 kJ/kg/degree C), soils often have a higher specific heat than air and heat up more slowly than the air.