Safflower Plant Irrigation Planning under Different Irrigation Management Using Aquacrop Model

Safflower is one of the most important oil crops whose yield decreases under water stress. Therefore, determining its response to different irrigation water managements is very important. To do that, in this study, AquaCrop model was used to simulate three irrigation scheduling strategies of safflower for drip, subsurface drip and furrow irrigation methods. At first, AquaCrop was calibrated using data collected from a research farm located at 34˚ 21’ N and 47˚ 9’ E, in Kermanshah, Iran. In the first strategy, apply irrigation up to field capacity at a constant rate (1, 5, 10 and 20 days), in the second strategy, apply a constant amount of irrigation water (values of 10 to 50 mm for drip and subsurface drip irrigation methods and values up to 10 90 mm for furrow method at constant duration 2 and 4 days for drip and subsurface drip irrigation and 10 and 20 days for furrow) and in the third strategy apply water stress levels of 100, 66 and 33% during the growing season for all three Irrigation method was considered. The results showed that the highest yield, biomass and water productivity were obtained in the first and second strategies. Maximum values for yield and biomass were 3.7 and 12.2 fon.ha-1, respectively, and maximum water productivity was 0.54 kg.m-3 in both drip and subsurface drip irrigation and 0.69 kg.m-3 in furrow irrigation. As the second strategy is easier for farmers to implement, it is suggested that this method be used. Therefore, for drip irrigation and subsurface drip scenario, it is recommended to apply 10 mm of irrigation water with a period of two days, and apply 30 mm water irrigation with a period of 10 days.