Abstract
Deficient irrigation is a very significant study, especially with the limited water. Therefore, the current research aims to study the deficit irrigation depending on several different scenarios, by adding different amounts of water and irrigation rates (10%, 30%, 50%, 70%, 90%) of the full irrigation with changing irrigation time and studying its effect on productivity. The results showed that there is a clear effect on the productivity of barley at the level of irrigation (10%-30%) of the full irrigation and for all irrigation dates when changing the date of the first irrigation only, while the results showed when changing the second irrigation only and the first and second irrigation at the level of irrigation (10% - 30% -50%) of the full irrigation, the productivity will decrease by 13.75 - 84.7 kg/ha. It was also noticed that changing the irrigation level for the first irrigation has a very small effect on productivity compared to changing the irrigation level for the second irrigation and for all irrigation dates, and the reason for this is the difference in the stages of yield growth. While the results showed that changing the irrigation level for the first and second irrigation together will have a greater effect on productivity than the rest of the other scenarios.