Two field experiments were conducted during the spring season 2020 in Karbala governorate to study the effect of irrigation systems, irrigation intervals, biofertilizers and polymers on some characteristics of vegetative growth and potato production. The results showed that there were significant differences in the values of the average plant height due to the effect of the double interference between the irrigation system and the improvers, The height of potato plant under any irrigation system was superior when adding conditioners compared to the control treatment, as it reached 48.56, 58.00 and 64.33cm when adding polymer, biofertilizer, and polymers+ biofertilizers, respectively compared with the control treatment of 44.64cm in the surface drip irrigation system. While it was 51.74, 58.19 and 64.67cm in the treatments of adding polymer, biofertilizers and polymers+ biofertilizers, respectively, compared with the control treatment 41.51cm under the sprinkler irrigation system, Also, there were significant differences in the values of average root lengths as a result of the effect of the double interference between the irrigation system and the improvers, as the potato root lengths under any irrigation system excelled when adding the improvers compared to the control treatment, It reached 36.29, 41.94 and 49.37cm when adding polymer, biofertilizers and polymers+ biofertilizers, respectively, compared with the control treatment 31.28cm at surface drip irrigation system. While it was 35.94, 40.69 and 48.14cm when adding polymer, biofertilizer, and polymers + biofertilizer, respectively, compared with the control treatment of 30.33cm at the sprinkler irrigation system, There were significant differences in the values of the total yield as a result of the effect of the double interference between the irrigation system and the conditioners, as the total yield of potato tubers under the two irrigation systems exceeded when adding the improvers compared to the control treatment, It reached 25.31, 28.86 and 36.90 μg ha when adding polymer, biofertilizers and polymers + biofertilizers, respectively, compared with the control treatment 17.21 μg ha at the surface drip irrigation system.
