Impact of Saline Water Irrigation (SWI) on Water Use Efficiency of Quinoa (Chenopodium quinoa Willd.) Under Tunisian Semi-arid Conditions

This study was carried out in Cherfech Tunisia, at the experimental station of the National Research Institute of Rural Engineering, Water and Forests (INRGREF) during the growing season 2015. The main objectives are quantifying and valuing the Water consumption (WC) and Water Use Efficiency of quinoa (Chenopodium quinoa Willd.), under saline water irrigation at different concentrations (T0 = 1.2 dS m-1, T1 = 9.2 dS m-1 and T2 = 18 dS m-1). The TDM decreased from 6.7 to 13.4% due to the increase in the salt concentration of the irrigation water from 9.2 to 18 dS m-1. A reduction of 9.8 to 12.6% was marked for treatments T1 and T2. Also, the WUE PR-anthesis has registered a decrease of 8 and 12.5% respectively for T1 (WUEPR = 10.3 kg m-3) and T2 (WUEPR = 9.8 kg m-3) compared with the control T0 (WUEPR =11.2 kg m-3). However, irrigation water salinity showed no effect on the WUE post-anthesis T0 and T1 (WUEPS = 3 kg m-3). Nevertheless, a decrease about 15% was recorded in the T2 (WUEPS = 2.5 kg m-3). At harvest, the highest, WUETDM (5.43 kg m-3) was recorded under T0. However, the lowest WUETDM (5 kg m-3) was marked under T2; a decline of 7.9% was marked. Besides, the uppermost WUEGY (2.09 kg m-3) was recorded under T0. However, the smallest amount of WUEGY (1.1 kg m-3) was recorded under T2. A lessen of 47.4% was manifested on WUEGY due to the height reduction on yield in the T2.