Carrot productivity and its physiological response to irrigation methods and regimes in arid regions

The aim of this study is to optimize water irrigation management for improving carrot productivity and water-saving in arid regions of southern Tunisia. Field studies were conducted over two seasons (2017-2019) to evaluate the effects of drip irrigation (DI) and surface irrigation (SI) methods coupled with three irrigation regimes on agronomic parameters of carrot crops. Irrigation regimes consisted of water replacements of cumulated crop evapotranspiration (ETc) at levels of 100% (I100), 70% (I70), and 40% (I40) when the readily available water in I100 treatment was depleted. Results showed a reduction in carrot yield by 13-22% and 22-32% with I70 and I40 treatments compared to I100, respectively. Yield is affected by the irrigation method with a reduction of around 6-7% under the surface method for both years. The water productivity (WP) was found to significantly vary among regimes and methods, where the highest values were observed for the I40 regimes and drip method. Drip and I100 irrigation techniques seem to optimize carrot production. Under situations of water shortage, adopting deficit irrigation treatment (DI70) could be an alternative for managing carrot irrigation and improving water productivity.