Understanding the various processes that drive plant growth
is critical for successful farming. Evapotranspiration (ET) is one such process
that has a major impact on agricultural productivity. Often overlooked, ET
plays a pivotal role in maintaining soil moisture levels and sustaining plant
Modern technologies, in particular remote sensing and accurate hyperlocal weather data, allow farmers to minimize the time and effort previously required to calculate and continuously monitor the level of crop evapotranspiration, especially in large fields. We’ll go through what evapotranspiration is, define how it affects crop yields, and discuss the techniques for making it easier to calculate and factor into your irrigation plans.
What Is Evapotranspiration?
The term “evapotranspiration” refers to the total amount of water evaporating and transpiring from the Earth’s surface. Evaporation of water from the soil surface, the capillary fringe above the groundwater table, and surface water bodies are all components of ET. Transpiration, the process through which water moves from the soil through plants and into the air, is also part of the evapotranspiration system.
Rain is water that falls from the sky; ET is water that rises from the earth; thus, you can think of evapotranspiration as the opposite of rain. Clouds formed by the condensation of water vapor from evaporation and transpiration eventually release their load of precipitation as rain or snow. ET is second only to precipitation in terms of importance to water resource management and determining how much water should be applied to farms through irrigation.
How does potential evapotranspiration differ from actual evapotranspiration?
Potential evapotranspiration refers to the capability to evaporate and transpire water from the surface when water is abundant. Actual evapotranspiration, on the other hand, refers to the amount of water lost from the surface owing to evaporation and transpiration. Both potential and actual ET can be used for agricultural applications.
Process Of Evapotranspiration
Two components of the evapotranspiration process, evaporation, and transpiration, are worth exploring in more detail. Evaporation is the transition of water from a liquid to a vaporous or gaseous state. Solar energy causes this effect on bodies of water as well as moist soil. When the water molecules absorb enough heat, they gain the energy necessary to leave the liquid’s surface and enter the air as vapor. This mechanism plays a crucial role in bringing moisture from the earth up into the atmosphere.
Transpiration, the release of water vapor into the atmosphere, is made possible by the microscopic pores (stomata) on the stems, leaves, and other aerial plant parts. During this part of the evapotranspiration process, the plant transports water from the ground through its root system to its aerial parts, where it evaporates. So, we may distinguish three distinct stages of transpiration:
* Roots draw moisture up from the ground;
* Water travels up through the plant, performing its vital functions along the way;
* Stomata “exhales” moisture into the atmosphere.