Determination of required irrigation water for sunflowers in the Ergene Basin using climate-data based heuristic models

The aim of the master's thesis titled "Determination of required irrigation water for sunflowers in the Ergene Basin using climate-data based heuristic models" is to estimate the required irrigation water amount for sunflowers, a highly important crop in the Ergene Basin. As the first step, reference evapotranspiration was calculated using the FAO-56 PM empirical formula. In the second step, potential evapotranspiration was calculated using the Blaney-Criddle empirical formula. In the third step, climate data including Rs, E, Tmax, Tort, Tmin, and Sh were used to calculate evapotranspiration using the MARS, OP- ELM, GMDH, and M5Tree heuristic methods, respectively. Among these methods, the GMDH method combining Rs, E, Tmax, Tort, Tmin, and Sh yielded the best performance with performance criteria of R2= 0.9846, MSE=49.07, MAE=5.56, and AARE=7.23 compared to the reference evapotranspiration. Finally, using the evapotranspiration values obtained from the best-performing method, the irrigation water requirement for sunflowers in the Ergene Basin was determined as 611.74 mm without irrigation efficiency and 764.68 mm for 80% irrigation efficiency, and the results were observed to be close to values obtained through experimental methods.