There are many things in the world that, at first glance, may seem difficult to understand, yet they are rich in reason. Take water, for example, which freezes into ice when the temperature drops below zero degrees Celsius. But why is it necessary to water wheat fields before the severe cold sets in to prevent the wheat from freezing?
As long as the temperature is above zero degrees, water is always evaporating to some extent and turning into water vapor. One characteristic of water vapor is that it can provide some insulation. After watering the wheat fields, the slowly evaporating water creates a layer of water vapor that retains the ground temperature, making it difficult for sudden cold to harm the crops.
If the cold becomes particularly severe, this layer of water vapor transforms to cope with it. When water vapor encounters extreme cold, it condenses, releasing a certain amount of heat in the process. This heat, in turn, fights the cold and protects the crops. Additionally, because water has a high specific heat capacity, it prevents the roots of the wheat from being damaged by sudden cold.
What happens if the cold continues and the water in the wheat fields can no longer evaporate, and the water temperature drops to 0°C? At this point, ice formation occurs in the wheat fields, yet this layer of ice still serves to protect the crops. Winter wheat is essentially in a dormant state; as long as the roots are well protected, even if the wheat sprouts are somewhat damaged, it will not affect their good growth in the coming year. However, it is important to note that wheat fields are not like rice paddies; watering must be moderate to prevent the formation of large pools of water and thick ice, which could affect the roots’ ability to breathe. A thin layer of ice not only does not severely affect the roots’ respiration but also blocks the severe cold, preventing it from penetrating through soil gaps and freezing the roots.
Watering to prevent freezing is a method that has been used not only in wheat fields but also in horticulture in recent years. Scientists have conducted experiments where, before the onset of a cold wave, some fruit trees and fruits were sprayed with water. A layer of ice formed around them provided protection, and after experiencing severe cold, these fruit trees and fruits remained alive; however, other fruit trees and fruits that were not sprayed with water suffered considerable freezing damage.