Comparative effects of direct seeding and transplanting on rice yield and water productivity under different irrigation methods

Abstract Water scarcity and soil degradation pose major challenges to traditional rice. This two-year field study (2019–2020) in northern Iran evaluated the potential of direct seeding as an alternative to transplanting to reduce water. The study examined four different irrigation methods (sprinkler, I 1 ; flooding, I 2 ; wet & dry, I 3 ; tape, I 4 ) and three cultivation techniques (direct seeding, C 1 ; direct seedling, C 2 ; traditional transplanting, C 3 ). The experiment followed a randomized complete block design with three replications. Throughout the season, applied water, yield, yield components and water productivity were measured and calculated. Overall, the results indicate that the direct cultivation method of rice (C 1 and C 2 ) consumed significantly less water than the traditional transplanting method (C 3 ). However, the direct method also resulted in a lower rice yield compared to the traditional method. The highest yield (8206 kg/ha) was recorded in I 2 C 3 . In C 3 , changing from I 2 to I 1 , I 3 , and I 4 , led to yield decreases of about 14 %, 9 %, and 11 %, respectively. The highest water use was recorded for I 2 C 1 (12 490 m 3 /ha). Transitioning from I 2 C 3 to I 4 C 2 led to a 24 % decrease in yield and a 45 % decrease in water consumption. In this scenario, physical and economic water productivity reached 0.9 kg/m 3 and 0.45 $/m 3 , respectively. The study suggests that direct seeding of rice, compared to the traditional method, can significantly reduce non-beneficial water usage. To address the reduction in yield and adopt water-saving methods, it is important to offer encouraging incentives.