Managing Drought Risk on Lentil Using Deficit Irrigation in Arid Zones

Grain legumes (pulses) are important crops for global food security, especially in developing countries. They also play an important role in enhancing sustainability through intensification and diversification of agricultural production systems. Meanwhile, the deficit irrigation strategy is one of the most important options for reducing water losses and maximizing water use efficiency in arid zones. A 2-year field experiment was conducted in the Agricultural Research Station, Higher Education Complex of Saravan during the growing seasons of 2018 and 2019. The experiment was split plot based on a randomized complete block design (RCBD) with four replications. The main plots included four levels of irrigation (60, 80, 100, and 120%). Subplots were two different landraces from Iran for lentil crop (Baluchestan and Kurdestan). The results revealed that the effect of deficit irrigation was significant on grain yield, biological yield, harvest index, and water use efficiency. Apart from the landraces, with increasing water consumption, the grain yield of control treatment (100%) grew by 107% in comparison to 60% irrigation treatment, but this elevation was not significant at 120% level in comparison to the control treatment. Further, 120% irrigation treatment led to reduction in water use efficiency. The highest water use efficiency (2.9 kg ha-1 mm-1 ) was obtained in 80% irrigation treatment with 10% reduction in grain yield compared with control treatment. The highest harvest index was observed in the interaction of Baluchestan zones × 80% water treatment (0.24). Although the interaction of Baluchestan landrace × 80% water treatment had 10% grain yield lower than control treatment, its biological yield decreased by 27% compared to control treatment, which eventually led to 20% rise of the harvest index. Thus, our study revealed that deficit irrigation was a useful method to protect the water resources and could be used in cultivation of other plants in arid zones.