Modelling of Crop Reference Evapotranspiration: A Review

Efficient irrigation water management requires a good quantification of evapotranspiration. The precise estimation of water requirement of crop is very important factor in the application of irrigation design and scheduling. Water relation model are essential component of all crop model because of critical role of water status has in determining growth, productivity and produce quality. Irrigation futures aim to identify an appropriate model for the calculation of reference crop evapotranspiration. Different climatological methods are using for estimating reference crop evapotranspiration on a daily basis. Some of these methods are based on combination theory and others are empirical methods based primarily on solar radiation, temperature and relative humidity. This paper evaluate and review the use of different evapotranspiration models and data in studies of geographical ecology it is also used in the estimation of daily water requirements for agricultural crops grown in different climatic regions of India and worldwide.