Interactive effect of soil types, seed source, and burial depths on seedling emergence, survival, and growth of Haloxylon salicornicum: implications for habitat-specific adaptations

In arid environments, understanding the interaction between soil type, seed source, and burial depth of seeds is vital for optimizing germination and seedling establishment. This study investigated the effect of these factors on the seedling emergence and growth parameters of Haloxylon salicornicum (Moq.) Bunge ex. Boiss. Soil and seeds were collected from three distinct habitats: wadi plains (WP), sand dunes (SD), and mountain slopes (MS) of Thadeq, Riyadh, Saudi Arabia. In a fully factorial reciprocal pot experiment, seeds and soil of each habitat were interchanged, with seeds sown at four burial depths (0, 1.5, 3.0, and 4.5 cm). The seedling emergence and early seedling growth parameters of H. salicornicum were assessed. The results showed significant interaction among soil type, seed source, and burial depth (p < 0.05). Pearson correlation analysis showed a strong positive correlation of germination indices and growth parameters with key soil parameters such as organic matter percentage (OM), CaCO3, HCO3, water holding capacity (WHC), and available macronutrients (NPK). The results suggested that H. salicornicum showed different emergence rates due to significant variations in soil texture, OM, NPK, and WHC. WP-Soil had the best seedling emergence percentage (GP), emergence rate, and germination energy (GE), which were highly correlated with coarse sand and silt+clay content. Furthermore, seedling emergence, survival, and growth were depth-dependent. The maximum GE and other germination indices were recorded in the seeds at the top layer, while the survival and growth were best depicted at shallow depth. Additionally, the growth parameters varied along the different soil types and were positively correlated with soil texture and WHC. The results emphasized the importance of soil traits and burial depth in seedling emergence, survival, and establishment of H. salicornicum in arid ecosystems. These findings give crucial insight into habitat-specific restoration strategies, which facilitate the conservation and sustainable management of H. salicornicum in desert ecosystems.