Estimation of Evaporation with Different Methods for Bapatla Region

The evaporation is basic need for the crop water requirement. When the water manager or formers are
going to plan of crop for a particular season kharif, rabi and summer to know the water requirement of the
crop to plane the optimization of the allocation of the resource. Accurate estimation of Evapotranspiration
is necessary step in water resources management. Evapotranspiration varies spatially and temporally.
Recently, the Food and Agricultural Organization has suggested FAO-56 PM method (modified PM
method) as a standard method for calculating reference Evapotranspiration (ET0), because this method is
applicable to all types of season and different climates and gives more accurate result when compared
with the physical methods like Lysimeter and Class A Pan. FAO-56 PM method cannot be debated by any
other old methods which require less data for calculating ET0. But FAO-56 PM requires very large
amount of meteorological data, which is not available at full climate stations. So there is need to find out
the next best suitable method after FAO-56 PM method, which will give ETO results nearer to FAO-56 PM
method. Here four different methods are considered for present study, which are radiation based,
temperature based and combine parameters based (FAO-56 modified Penman Monteith, Hargreaves,
Blaney-Criddle, Modified penmen are the methods). The present study concern on the Bapatla region it
concern most of the area under irrigation for that purpose which they need to give the daily evaporation
data. In this study concerned for last 10 years data taken to analyze. Finally the FAO-56 PM has gave the
consistence of the evaporation. So further calculation of evaporation for the Bapatla region has follow to
the FAO-56 PM method to calculate the evaporation.