Assessing a suitable method in estimating Evapotranspiration for crop water requirement

Tamilnadu is a water scared state deficient in both ground water and surface water. Efficient water management techniques are required for maximizing yield of any crop that requires estimating crop water requirement in a reliable manner and realistic manner. Evapotranspiration is an essential component of the hydrological circle and its accurate estimation is necessary for many hydrologic studies. References crop Evapotranspiration (ETo) is independent of crop type and depends on climate and is a basis for computation of water requirements for crops it also plays significant role for the distribution of water on the earth surface and a major determinate variable in water cycle. A way of estimating Evapotranspiration may provide an insight to crop water requirement. The demand of the any crop can be computed by multiplying reference crop Evapotranspiration with crop co-efficient. To date, a lot approach are available for ET estimation, each method has its own advantages and disadvantages. Assessing a suitable methodology is focus of this paper.