In light of the scarcity of irrigation water, extreme wastage of water, saline soils, and the dominance of traditional water management methods, the presented research transpired in 2020 in the Directorate of Agriculture, ALHashimiya area, Hilla City, Iraq. The latest study aimed to investigate the effects of subsurface drip irrigation system (SDIS) and flood irrigation system (FIS), with three drip irrigation distances of 18, 20, and 22 cm on two rice (Oryza sativa L.) cultivars, i.e., ‘Tarm Hashemi’ (TH) and ‘Daillman Mazandarani’ (DM). The irrigation systems (SDIS and FIS) significantly impacted the growth and productivity traits of the rice crop. The SDIS ensures the addition of an appropriate amount of water to the plants by keeping wet the root zone without wasting water compared with the flood irrigation system. The interaction of rice cultivar Tarm Hashemi, SDIS, and drip irrigation distance (DID of 18 cm) resulted in the best performance for root growth traits, i.e., root length and root fresh and dry weight (17.66 cm and 1.80 and 0.85 g, respectively). It also provided the highest plant vigor index (PVI), biological, and grain yield (71.15 cm, 1,747.23, and 608.26 g.m^-2, respectively). Cultivar Tarm Hashemi proved superior to cultivar Daillman Mazandarani in managing the morpho-yield traits. The subsurface drip irrigation system during the growing season helped increase the productivity of the rice crop compared with the traditional irrigation system. Compared with FIS, the SDIS not only improved and enhanced the growth and grain yield, but also saved abundant water and nutrients.

Keywords: Rice (Oryza sativa L.), cultivars Tarm Hashemi (TH) and Daillman Mazandarani (DM), subsurface drip irrigation system (SDIS), flood irrigation system (FIS), drip irrigation distance (DID)

Key findings: The study focused on achieving the best growth results for the rice (Oryza sativa L.) crop, with the highest productivity emerging with the subsurface drip irrigation system and the planting distance of 18 cm. The reaction of rice cultivar Tarm Hashemi (TH) to the subsurface drip irrigation system gave the highest studied characteristics compared with the rice cultivar Daillman Mazandarani (DM).