Also occurs when water fills pores the air must be displaced. Occurs due to diurnal temperature differences between the soil surface and the bulk atmos. Only important in the top few inches of soil. Some wetlands may be flooded daily and some may never be flooded. Especially important in desert regions where hot winds blow from the desert across irrigated fields and increase evapotranspiration.
High temperatures result in molecules having higher vibrational and translational energies.
When hot molecules collide with cold molecules, this energy can be transferred and hence heat flows. 10.2 Factors affecting the amount of energy entering the soil 1. Latitudinal position on the earth 4. In cold climates can inhibit or delay seed germination In warmer climates, prevents moisture loss and keeps plant roots a little cooler.