The study of crop response to water deficit is important in areas where water resources are limited. This study was carried out over the period 2008-2011 in order to study the effect of water deficit on the productivity of berseem in the Tadla region. Four water regimes (100 %, 80 %, 60 % and 40 % ETc) were compared under both flood and drip irrigation techniques. Observations were made on the soil, biomass at each cut and root system. The results showed that the average annual maximum yield obtained was 16.2 t.ha-1. Reductions in yields by applying 60 % of water inputs are 40 % and 42 % in 2009/10 and 2010/11, respectively. The contribution of cycles without irrigation to annual biomass yield varies from 35 % under 100 % ETc to 52% under 40 % ETc. Water use efficiency of berseem over the over the entire crop period is 3.37 kg.m-3. The maximum average yield obtained under drip irrigation was 15.7 t / ha. It was obtained with a water supply of 411 mm which allowed a saving of 57 % of water supply versus flood irrigation technique. 

Key words:  Berseem, water stress, flood irrigation, drip irrigation, water use efficiency, Morocco.