Effect of Potassium silicate and organic fertilization on vegetative traits of some ornamental shrubs under salt stress

The experiment was conducted in lathhouse belonging to the Babylon Agriculture Directorate Khanfara Nursery from November 2024 until October 2025. To study the effect of Potassium silicate and organic fertilization on vegetative traits of some ornamental shrubs under salt stress, the experiment included three factors: salt stress (three salinity levels of irrigation water, 3.6 dSm⁻¹, designated S1, S2, and S3); the second factor, humic acid at three concentrations (0, 5, and 10 g.L⁻¹, designated H1, H2, and H3); and the third factor, potassium silicate spray (52.8% silicon dioxide, SiO₂) at three concentrations (0, 150, and 200 mg.L⁻¹, designated Si₁, Si₂, and Si₃). The research was conducted as a 3x3x3 factorial experiment with a randomized complete block design (RCBC). With three replicates, the arithmetic means were compared using the least significant difference (LSD) test. The results were as follows: The salt stress treatment at a concentration of 6 ds m⁻¹ resulted in the lowest average height for Tecoma and Rose of Jelly plants (123.33 and 118.33 cm, respectively), the lowest number of leaves (32.72 and 45.72 leaves per plant, respectively), the lowest leaf area (2871.33 and 1904.21 cm², respectively), the lowest stem diameter (144.17 and 1.75 cm, respectively), and the lowest number of branches (6.16 and 6.44 branches.plant-1, respectively). The humic acid spray treatment at a concentration of 10 g L⁻¹ was excelled, resulting in the highest average plant height for Tecoma and Hibiscus (140.91 and 147.93 cm, respectively). The average number of leaves was (45.48, 65.11) leaves/plant, the average leaf area was (5748.33 and 4348.12 cm²), the average stem diameter was (194.68, 2.16 cm), and the average number of branches was (7.94, 9.14) branches.plant-1. Regarding potassium silicate spraying, the treatment with a concentration of 200 mg.L-1 resulted in the highest average plant height (140.97, 147.39 cm), average number of leaves (44.48, 62.17) leaves/plant, average leaf area (4405.53 and 3448.41 cm²), average stem diameter (183.69, 2.11 cm), and average number of branches (8.98, 8.84) branches.plant-1. The triple interaction coefficient was recorded between (Without salt stress + spraying with humic acid at a concentration of 10 g.L -1 + spraying with potassium silicate at a concentration of 200 mg.L -1) Highest average for the studied traits.