Impact of irrigation methods using saline water on carrot yield, water productivity and soil salinization

A two-season study (2017-2019) was conducted to assess the effects of surface and drip irrigation methods using saline water (ECi of 7.4 dS/m) on soil salinization, yield, and water productivity of carrot in arid regions of Tunisia. The results indicate that drip irrigation resulted in higher carrot yields (32.6 and 32.5 t/ha) compared to the surface method (30.1 and 30.4 t/ha) due to better soil moisture and lower salinity levels. However, for both methods, no significant differences were observed between the two seasons due to the amounts and distribution of rainfall events. Drip irrigation (6.3 and 6.2 kg/m3) was more water-productive than surface irrigation (5.7 and 5.4 kg/m3), following the same scheduling rule, due to higher yield and reduced water use. The relative difference in WP can have a positive economic impact in terms of farm productivity and sustainability. Compared to initial values, the reduction in soil salinity at harvest was due to salt leaching caused by rainfall. Higher soil salinity was observed with surface irrigation compared to drip irrigation, possibly due to increased evaporation from the soil between the respective irrigation sessions. Therefore, farmers under these conditions should re-think about their common choice of irrigation method.