Arid and semi-arid regions, which cover a large proportion of Iran’s rangelands, are among the most vulnerable ecosystems due to low precipitation, high evaporation, and uneven rainfall distribution. These conditions result in increased surface runoff, reduced soil infiltration, and severe limitations in water resources. Implementing strategies such as rainwater harvesting techniques and soil amendment treatments has the potential to enhance soil moisture retention, minimize evaporation losses, improve water-use efficiency, and ultimately support the sustainability of vegetation cover. In the present study, the effects of different rainwater harvesting methods and soil amendment treatments on the establishment and growth of two rangeland species, Aellenia subaphylla and Artemisia sieberi, were evaluated in the desert rangelands of Jajarm, Iran. The experiment was conducted as a factorial arrangement within a randomized complete block design with four replications. Three rainwater harvesting methods including crescent-shaped catchments, pitting, and contour furrows, were tested in combination with soil amendment amendments including two levels of acrylic clay nanoparticles, Glomus intraradices, Glomus mosseae, Glomus fasciculatum, straw mulch, two levels of zeolite, and a control. Vegetation parameters such as establishment rate, canopy cover, plant height, and major and minor diameters were measured during the first year after establishment. The results showed that A. subaphylla achieved the highest establishment rate (71.21%) under the contour furrow method, while A. sieberi recorded its highest establishment rate (86.11%) under the pitting method. Conversely, the crescent-shaped catchment resulted in the lowest establishment rates for both species. Soil amendment treatments did not exhibit significant effects on either species. Significant differences among rainwater harvesting methods were observed in terms of major and minor diameters for A. subaphylla, and in major diameter and canopy cover for A. sieberi. Overall, the findings suggest that while rainwater harvesting methods play a critical role in improving the establishment of rangeland species, long-term studies are required to fully evaluate the impacts of soil amendment treatments.