Silicon can significantly enhance crop productivity, especially in semi-arid areas which exhibit low organic matter content, leading to insufficient water retention and nutrient imbalances that can negatively impact crop yields. In current investigation, we assessed the positive influences of nano-silicon and various fertilizer treatments on Carthamus tinctorius yield and morphological traits. The treatments included the spraying of 0.0- and 20-mM nano-silicon in combination with fertilizers, including a control group, 90 kg‧ha-1 NPK (nitrogen, phosphorus, and potassium), and organic manure at rates of 15 and 30 t‧ha-1 which were tested at Maragheh (37°23′N; 46°14′E), Iran. Principal components (PC) analysis revealed that PC1 and PC2 described for 50% and 20% of the observed variation, respectively. A positive association was observed among straw yield, seed yield, height of the first branch, and harvest index. The NPK treatment with 20 mM nano silicon resulted in high seed yield, while the usage of 30 t‧ha-1 organic manure with 20 mM nano-silicon showed increased morphological and yield components. Cluster analysis of measured traits and treatment combinations generally supported the results of the PC analysis but revealed some differences, particularly in the separation of organic manure fertilizers based on consumption levels. For achieving sustainable farming goals, apply 30 t ha-1 of organic manure with 20 mM nano-silicon, improves biomass and yield components. This study underscores the positive impact of nano-silicon on safflower growth and emphasizes the potential benefits of its foliar application in conjunction with NPK or organic fertilizer to enhance Carthamus tinctorius performance in upland semi-arid regions.
