Sulphur fertilizer can be used as a soil amendment in semi-arid region. The current field trial aimed to study the effect of different levels of various sulphur fertilizers (control: no sulphur application, utilization of 25 or 50 kg S from single superphosphate: P+S25 or P+S50, 25 or 50 kg S from the elemental form: S25 or S50, 25 or 50 kg S from zinc sulfate: Zn+S25 or Zn+S50) on growth and qualitative proprieties of safflower in west of Iran. The application of sulphur increased vegetative growth components such as plant height, first capitulum height, stem diameter, and the number of lateral branches. The highest rate of vegetative growth was obtained with the application of zinc sulfate. Chlorophyll content increased by 21-24% with zinc sulfate compared to the control. The widest canopy was recorded under the conditions of the use of Zn+S50 and P+S50 (a 53% increase). Regardless of the amount of consumption, the highest plant dry weight was obtained with the use of Zn+S and S. Utilization of the high level of zinc sulfate and elemental sulphur by increasing the number of capitula, number of achenes in capitulum and diameter of capitulum improved achene yield (by 17%). The highest amount of achene oil was achieved by S50 and the application of P+S50 was in the second rank. However, consumption of all levels of S or Zn+S and P+S50 caused a significant increase in achene protein content. The highest amount of oleic acid, stearic acid, and palmitic acid was obtained with the use of Zn+S. Altogether, under farmyard applied conditions, elemental sulphure and zinc sulphate significantly improved safflower performance due to its high S content, slow S releasing property and low leaching. Application of elemental sulphure and zinc sulphate in semi-arid areas should be seriously considered.
