Page 15 - soil-plant-water relationship and water requirement

SOIL-PLANT-WATER RELATIONSHIP AND WATER REQUIREMENT

CHAPTER 2

2.0 EVAPORATION, EVAPOTRANSPIRATION AND INFILTRATION

2.1 EVAPORATION PROCESS

When a liquid substance turns into a gas, it is called evaporation. Water evaporates
when it is heated. Because the molecules travel and vibrate so swiftly, they escape into
the atmosphere as water vapour molecules. The water cycle is incomplete without
evaporation. The evaporation process is powered by solar energy, or heat from the sun.
It absorbs moisture from garden soil as well as the world's largest oceans and lakes.

2.1.1 Factors That Affect the Evaporation

 Temperature: As the temperature increases, the rate of evaporation also
increases. Temperature and rate of evaporation are proportional to each
other.
 Surface area: As the surface area increases, the rate of evaporation
increases. The surface area and rate of evaporation are proportional to each
other.
 Humidity: The rate of evaporation decreases with an increase in humidity.
Humidity and the rate of evaporation are inversely proportional to each
other.
 Wind speed: Increase in wind speed results in increased evaporation. Wind
speed and rate of evaporation are proportional to each other.

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