Supplemental irrigation is used to uphold even soil moisture levels by irrigating the fields during critical and dry periods to balance the scarcity of soil moisture in later growth stages and save the crops. The exact amount of water added and timing are explained in this practice. Additionally, some examples of the application of supplemental irrigation such as in wheat production in Morocco are detailed. Finally, some general practices that are important for improving the efficiency of supplemental irrigation such as crop varieties, seeding rate and nitrogen application are explained.