Investigation of possibility of mapping potential evapotranspiration of reference plant and water requirement of wheat using different methods of mapping

Suitable water management in irrigation and drainage networks without mapping water requirement of different plants in macro levels is not possible. Iran was located in arid climate and has Drought problems and management of Drought, need to macro management of its water resources. In this study using meteorological data in Khuzestan, reference evapotranspiration and Wheat water requirement was determined in pilots. Finally different methods of mapping for example regression method, Inverse Distance Weighted and Co- Kridging were evaluated. In calibration stage power and logarithmic regression presented suitable results and have 8 and 16percent error respectively. Result show that ET0 and water requirement have significant relation with height. So these parameters have spatial continuity. In evaluating stage,  The result show that Co- Kridging method with  0.82 R2 (regression coefficient) , 0.66 d(Agreement index)  , 22.9 Root Mean Square Error  and 0.05 Normal Root Mean Square Error  and  5 percent Normal error  has lowest error in estimation of water requirement  of wheat and using this method can mapping water requirement with well accuracy. So Co- Kridging method is the best method between other methods. Use map obtained can has suitable conclusion from wheat water requirement changes in Khuzestan and manage crop pattern base of maps.