The effect of saline shallow ground and surface water under deficit irrigation on (Carthamus tinctorius L.) in semi arid condition

A number of column experiments were conducted in order to determine groundwater contributions by safflower (Carthamus tinctorius L.) under different saline shallow groundwater (Gw), surface water (Sw) and deficit irrigation schemes. The plants were grown in 16 columns with 0.40 m diameter and were packed with silty clay soil. The four replicate randomized complete block factorial experiments were carried out using different treatment combinations. Four treatments were applied during each experiment by maintaining ground and surface water of EC of 1 or 10 dS/m at water table level of 0.8 m under deficit irrigation condition (75% crop evapotranspiration). The groundwater contribution was determined as a part of crop evapotranspiration by analyzing daily readings of the water levels in Mariotte tubes. The additional surface irrigation requirements for different treatments were applied by adding water of EC of 1 or 10 dS/m. The average percentage of groundwater contribution to different treatments including (Gw = 1, Sw = 1 dS/m), (Gw = 1, Sw = 10 dS/m), (Gw = 10, Sw = 1 dS/m), (Gw = 10, Sw = 10 dS/m) with water table level of 0.8 m were found to be 58.5%, 14%, 15% and 3.5% of the average annual safflower water requirement, respectively.

► Groundwater contribution by safflower was studied under low and high salinity and water stress conditions.
► Increasing surface and groundwater salinity resulted a significant reduction in groundwater contribution.
► Surface irrigation can be managed to increase crop water requirement from shallow groundwater.
► The planting of safflower under both salinity and water stress conditions not recommended.