The effects of sowing seasons and chemical, organic and biological fertilizer sources were explored on morphological traits of dragon’s head (Lallemantia iberica Fish.) in a field experiment based on a randomized complete block design in three replications and six treatments. The fertilization treatments included organic fertilizers (vermicompost, manure, and humic acid), biological fertilizer (Thiobacillus mixed with sulfur), chemical fertilizer (macro NPK), and control (no-fertilization). The recorded traits included leaf area index, plant height, number of flower cycles per plant, number of achenes per plant, number of seeds per plant, 1000-seed weight, number of auxiliary branches, plant diameter, and the uptake of nitrogen, potassium, phosphorus, calcium, and sodium. The results showed that the winter sowing outperformed the spring sowing by a wide margin and results obtained for morphological traits were significantly higher than those of the spring sowing. The fertilization of the plants in both sowing seasons, especially in the winter sowing, improved yield and yield components. The uptake of N and K was not influenced by the sowing season and fertilizer type, whereas the uptake of P, Ca, and Na was influenced by these factors but with a slight difference. It can, so, be inferred that the uptake of nutrients in dragon’s heads is less influenced by the environment. Overall results indicated that the improvement of morphological traits in the ecological conditions of Azerbaijan region (Iran) was most notable for winter sowing of dragon’s heads with the use of Thiobacillus and vermicompost fertilizers.
