Page 8 - Azerbaijan State University of Economics

XiaolinQu, M.S., Lal K. Almas: The water requirement and profitability analysis of corn using irrigation
management approaches including evapotranspiration and weather data

major confined animal feeding industry. Thus, in order to efficiently utilize the

declining groundwater supplies through efficient irrigation practice, it is claimed

that there is a need for utilizing daily Evapotranspiration (ET) data for numerous

crops grown within this intensive northern Texas agricultural region to provide

accurate water use data to these agricultural producers.

ET is the combination of the concepts of both evaporation (E) and

transpiration (T) to describe the total water escaping from a crop to the air (Rogers,

2007). Evaporation is referred to the process of water-molecule transferring from

any moist surface to the air. Transpiration is the process of the water vapor

escaping from plant leaves from the tiny pores scattered over the leaf surface.

Since those two processes are closely intertwined and difficult to separate, ET is

always referred to as “crop water use”.

Soil moisture, natural precipitation and irrigation application are three sources

to meet ET requirement. Crop water use determines how much water is needed that

may be provided by rain, or both rain and irrigation. The accurate application of

crop water use is important because too little water can reduce crop yield while too

much water, which is irrigation, can lead to waste of energy and water as well as

accelerate the depletion of water resources.

When calculating ET for a specific crop, Potential Evapotranspiration (PET) is

used. PET is the amount of water that a well-irrigated crop uses (Colette, 2004).

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