ABSTRACT
The water vapor flux in agroecosystems is the second largest component in the hydrologycal cycle. Water vapor flux or evapotranspiration (ET) from the vegetation to the atmosphere is a widely studied variable throughout the world. ET is important for determining the water requirements for the crops, climatic characterization, and for water management. The estimation of ET from vegetated areas is a basic tool to compute water balances and to estimate water availability and requirements. In the last 60 years, several methods and models to measure the water flux in agroecosystems have been developed. The aim of this chapter is to provide a literature review on the subject, and provide an overview of methods and model developed which are widely used to estimate and/or measure ET in agroecosystems.
