A field experiment was conducted during the spring season 2020 in Karbala proving/ Al-Sharia Distrit, located at latitude N 32° 42' 13.8" and longitude E 43° 54' 36.6" and at an altitude of 27 m above sea level. The experiment included a study of two factors: the first, Irrigation Interval, three treatments were used: irrigation treatment every 2 days, Irrigation treatment every 4 days, and Irrigation treatment every 6 days. The second factor is the addition of soil conditioners, in which four treatments were used: the control treatment without any addition, the treatment of adding bio-organic fertilizers, the treatment of adding water-conserving technology (polymer), and the treatment of adding water-conserving technology + fertilizers Organic vitality. The experiment was designed according to the randomized complete block design (RCBD) with three replicates and under the split block design (split block design).It use the results of regional climate models to highlight how climate change affects the region through the AquaCrop model and repeat the same process for another regional climate model and another scenario to assess the impact using climate projections and analyzing the impact of climate change on water resources, the results were as follows: An increase in the amount of annual rainfall and monsoon rain during the two periods (2016-2035) and (2046-2065) under the RCP4.5 scenario, amounting to 17.00, 9.42, 11.91, and 9.06 mm. respectively compared to the base period (1985-2005) and its increase during the period (2016-2035) according to the RCP8.5 scenario amounted to 3.97 and 4.51 mm, with a slight decrease during the period (2046-2065) amounting to -3.78 and -2.57 mm, respectively, compared to base period. An increase in the maximum and minimum temperatures, according to the climate change scenario RCP4.5, amounted to 0.81, 0.75, 1.65, and 1.55°C, and the RCP8.5 scenario amounted to 1.1, 0.98, 2.33, and 2.14°C, as an average of the values of climate models. (EC-Earth, CNRM-CM5, GFDL-ESM2M) for the maximum and minimum temperatures, respectively, during the period (2016-2035) and (2046-2065), compared to the base periodd. There were no significant differences between the current productivity of the potato crop and the expected productivity using the AquaCrop model, so the value of R2 was 0.85 between the expected and measured data for productivity for twelve years under the surface drip irrigation system.The correlation coefficient (r) was 0.951, the root mean square error (RMSE) was 2.426, and the efficiency coefficient was 0.659 for the surface drip irrigation system.
