Consumptive Use and Evapotranspiration

Firstly, we have to cover the concepts of evaporation and transpiration as a prerequisite to learning about consumption use and evapotranspiration. During evaporation, water is lost from the earth’s surface, including water bodies and soil layers, while transpiration refers to the loss of water from plants. A combination of evaporation and transpiration, evapotranspiration is the loss of water from the surface of the earth as well as from plants. Consumptive use represents the amount of water needed by the plant and the water lost as a result of transpiration. In this article, we will discuss evapotranspiration and consumptive use in more detail.

What is consumptive use?

The term “consumptive use” is used to describe the loss of water during evaporation, as well as the water it takes to meet this loss and transpire through the leaves. Most often, consumptive use refers to just crops but it is a broader concept. Along with crops, it can also be used in farming, valleys, and other land-related projects. Consumptive use is defined mathematically as volume per unit area. Simply put, it refers to the aquatic depth of the irrigated area. There is a term known as ‘return flow’ that describes water that does not evaporate, transpire, or is consumed by plants. Instead, it seeps back into the ground and is then returned to the aquifer. 

The irrigation system on farms has a lot to do with it. It is, therefore, crucial to determine the irrigational needs of a specific farm based on the concept of consumptive use. Consumptive use is influenced by many factors such as soil type, topography, water supply, and most importantly climate. Temperature, humidity, sunlight, and wind movement are the four most influential climate factors in consumptive use.

Consumptive use is essential because then it is easy to plan crop patterns keeping in mind the location in which the irrigation system needs to be set up concerning water supply. It can be used to design an entire irrigation project. Furthermore, consumptive use can also be used to determine how much water should be released from the reservoir for irrigation. It is generally less in Kharif season when compared to rabi season.

What is Evapotranspiration?

Evaporation and transpiration constitute evapotranspiration. Transpiration happens when plants send water from their leaves to the air, whereas evaporation occurs when water moves from the soil and water surface to the air. Evaporation is a process without forces or factors, however, transpiration involves processes such as osmotic pressure, diffusion, and vapor pressure. A plant consumes water for the process of transpiration, which in turn activates evaporation. A complete cycle is present, for instance, when the crops grow, the water moves continuously from the soil to the roots, and from there it moves to the plant’s stems and leaves and finally to the atmosphere through transpiration.

Plants retain only a small percentage of the total water they absorb through their roots. Because the remainder of the water is used in all of the plants’ other processes, the rest is absorbed into the atmosphere via transpiration. There is a portion of soil water that evaporates directly into the atmosphere. Evapotranspiration is measured by an irrigation controller.

Evapotranspiration has gained relevance in recent years because it is thought to have the capacity to replenish freshwater supplies by continuing the hydrological cycle. Evapotranspiration is thought to be the most significant part of the hydrological cycle. As a result, correct ET calculations are also required since they may aid in the efficient management of irrigation and water distribution. Other advantages of ET include environmental evaluation and the protection of surface and groundwater quantity and freshness of water.

Relation between ET and Consumptive Use

The main difference between consumptive use and evapotranspiration is the way they are used. Potential evapotranspiration incorporates the idea of consumptive usage, as there is a large amount of water that cannot be reused or recovered, and instead considers plant consumption of water that evaporates. Water vapors are formed when water evaporates or transpires and is absorbed by the atmosphere. This water cannot be reused after it enters the environment since it is essentially devoured by the atmosphere. ET may be defined as the amount of water that has been used by systems such as plants, the atmosphere, the soil, and so on.

Conclusion

The information obtained from potential evapotranspiration is crucial in constructing an appropriate and accurate budget. Setting a budget while installing an irrigation system is critical, and it is also the first step toward water management. ET stands for the quantity of water required and the amount of water left over after it has been used. Without knowing the ET statistics, it’s tough to make a budget. Although, there is a slight difference between consumptive use and evapotranspiration they both go hand-in-hand. As a result, understanding evapotranspiration and how it relates to consumptive usage is critical. The information may also be used to reward farmers or landowners that conserve water and instead utilize it to recharge groundwater.