Around the world humans are involved in the production of a variety of plant crops. Many of these crops grow in environments that are naturally short of water. As a result, irrigation is used to supplement the crop's water needs. Managers of these crops can determine how much supplemental water is needed to achieve maximum productivity by estimating potential and actual evapotranspiration. The major source of this energy is from the sun.
Wind is the second most important factor influencing potential evapotranspiration .
Wind enables water molecules to be removed from the ground surface by a process known as eddy diffusion . The rate of evapotranspiration is associated to the gradient of vapor pressure between the ground surface and the layer of atmosphere receiving the evaporated water.