A model of correction indexes determination for Virginia type tobacco on the basis of field measured ETP

Numerous methods of calculating ET0 and ETP offer a great practical possibility for their application, but in order to improve their efficiency it is necessary to check them in particular regions. The experimental study of Virginia type tobacco in irrigation conditions was carried out in the area of village Brzi Brod (Niš). The established potential evapotranspiration of Virginia type tobacco ranged from 498.1-512.7 mm, depending on annual weather conditions. Highly significant correlation coefficients were found between the directly observed ETP of Virginia type tobacco and reference evapotranspiration (ET0) calculated by the following methods: FAO-56 Penman-Monteith (r=0.88), FAO-24 Radiation (0.79), FAO-24 Blaney-Criddle (r=0.85), Tornthwaite (r=0.90) and Hargreaves (r=0.76). The established correction indexes for translation of ET0 calculated by each method were the following: FAO-56 Penman-Monteith - 0.91; FAO-24 Radiation - 0.76; FAO-24 Blaney-Criddle - 0.89; Tornthwaite - 0.92; Hargreaves - 0.72