الفهرس 
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Abstract
A field trial was conducted at Sakha Experimental Research Station, Kafr El-Sheikh Governorate, Egypt during the two successive winter seasons of 2018/2019 and 2019/2020 to calibrate and validate the AquaCrop model (Version 5). Two cultivars of canola (Serw4 and Serw6) were sown to study the influence of two irrigation regimes (50 and 70% of soil moisture depletion SMD) on canola yield, seed quality and water productivity. After finishing the previous experiment, Aquacrop model was evaluated by comparing field results with predicted results by model under the same treatments. AquaCrop model was calibrated using the dataset of 1st season and validated using the 2nd season dataset by various statistical indicators i.e. coefficient of determination (R2) and degree of agreement (d). Also, the simulation of climate change impact on canola yields was done. The results obtained could be summarized as follows:- Seed and biomass yield (Mg h-1). The irrigation regimes and canola cultivars differently affected seed and biomass yield (Mg ha-1) of canola plants during both seasons of the experimentation, where the effect of irrigation regimes was significant, while the effect of canola cultivars was significant only for biomass yield (Mg ha-1) in the first season and non-significant for other aforementioned traits. Also, concerning the interaction influence between the treatments under investigation, data show that there are non-significant differences between all of the interactions. The irrigation at 50% depletion from soil moisture gave the best seed and biomass yield (Mg ha-1) of canola plants compared to 70% depletion from soil moisture and there are significant differences between such treatments. This trend was found with both canola cultivars but the Serw4 recorded values higher than Serw 6. - Flowering and maturity dates. The effect of irrigation regimes was significant, while non-significant influence was found on the values of flowering and maturity date (DAS) of canola plants, except maturity date (DAS) in 2ndseason which had a significant effect, due to using the different canola cultivars. Also, concerning the interaction influence between the treatments under investigation, there are non-significant differences between all of the interactions. With respect to the effect of depletion,the values of flowering and maturity date (DAS) are higher with canola (Serw4 and Serw6) plants irrigated at 50% depletion from soil moisture compared to 70% depletion from soil moisture and there are significant differences between such treatments. On the other hand, Serw 4 recorded values higher than Serw6. - Oil and protein percentages. the effect of irrigation regimes on oil and protein percentages in canola seeds was non- significant at 1st season and significant at 2nd season. While the effect of canola cultivars alone (C), as well as interaction effect (C×I), were non-significant at both seasons. The irrigation at 50% depletion from soil moisture gave the best oil and protein percentages in canola seeds relatively compared to 70% depletion from soil moisture. This trend was found with both canola cultivars but the Serw4 recorded values higher than Serw6. Such an effect was the same during the two seasons of the experiment. Total water applied. Increasing the levels of depletion from soil moisture caused decreasing total water applied. In the first season; total water applied decreased from 3500 m3 ha-1 in case of 50% depletion to 3150 m3 ha-1 for 70% level of depletion with canola plants (Serw4), while total water applied decreased from 3395 m3 ha-1 in case of 50% depletion to 2730 m3 ha-1 for 70% level of depletion with canola plants (Serw6). In the second season; total water applied decreased from 3605 m3 ha-1 in case of 50% depletion to 3360 m3 ha-1 for 70% level of depletion with canola plants (Serw4), while total water applied decreased from 3500 m3 ha-1 in case of 50% depletion to 2905 m3 ha-1 for 70% level of depletion with canola plants (Serw6). Water productivity. The water productivity) W.P) reflects the capability of a unit of applied irrigation water in producing the marketable yield. Regarding the influence of irrigation at different levels of depletion from soil moisture on W.P, the highest values of W.P were obtained by irrigation at 50 % depletion from soil moisture under both canola cultivars at both growing seasons, except W.P under canola (Serw6) in 1st season, where the highest values of W.P were obtained by irrigation at 70 % depletion from soil moisture. This may be due to increasing the seed yield of canola in case of irrigation at 50% sharply as compared to other treatment. The highest value of water productivity (0.64 and 0.66 kg m-3in 1st and 2nd seasons, respectively) could be achieved when canola plants (Serw4) exposed to 50 % depletion through the season. - Testing AquaCrop model by comparing observed values with predicted. The results show that AquaCrop model (Version 5) is able to simulate well seed and biomass yield of canola cultivars as well as canola water productivity under different irrigation treatments at the studied region, where, values of R2 and d record a robust agreement among predicted and observed values. As for the simulation of climate change influence, the findings indicate that increasing temperature leads to increasing the reduction percentage of seed yield of different canola cultivars, and the reduction percentage with Serw6 was more than Serw4. The AquaCrop model was able to simulate well seed, biomass yield and canola water productivity of different cultivars under different irrigation regimes and climate changes at North delta region (Egypt). Thus, farmers, project managers, irrigation engineers and consultants can use this model as a decision support tool in increasing seed, biomass yield and canola water productivity.