Quantitative Assessment of Deep Root Irrigation Efficiency for <scp> <i>Haloxylon Ammodendron</i> </scp> Establishment in Desert Ecosystems

ABSTRACT Wind erosion control is critically important in arid regions like Iran, where challenges such as limited precipitation, high temperatures, and substantial evaporation hinder vegetation establishment. This study examines the effects of deep root irrigation using PVC pipes and sand donut systems, compared with traditional surface irrigation (with a uniform 15 L water volume), on the morphological characteristics of Haloxylon ammodendron to enhance its establishment in Qom Province, a desert region of Iran. Over a six‐month period (May to October), various plant characteristics were assessed, including height, root depth, aerial and root biomass, trunk diameter, growth index, and canopy diameter. The results showed that while the sand donut treatment did not significantly differ from the control in most plant traits, the PVC pipe irrigation led to substantial improvements. Specifically, plants irrigated with PVC pipes exhibited increases of 47.98% in height, 55.38% in root depth, 34.40% in trunk diameter, 66.92% in aerial weight, 95.61% in root weight, 28.27% in canopy diameter, and 37.92% in growth index compared with the control. Moreover, the wider canopy formed by the PVC treatment effectively reduced wind speed, which is crucial for mitigating wind erosion. This effect was most pronounced in the PVC treatment, followed by the sand donut treatment, and then the control. Wetting pattern analysis revealed that deep irrigation with PVC pipes achieved a wetting depth of 100 cm, which was 40 cm deeper than surface irrigation. Considering Iran's water scarcity challenges, this study recommends adopting deep root irrigation with PVC pipes (12.5 cm diameter and 55 cm height) to optimize water use efficiency and enhance vegetation establishment, thereby contributing to sustainable land management in desert ecosystems.