Interactive effect of potassium and zinc application on oil yield of sunflower

Several initiatives have been made in Egypt to increase the overall production of oil crops, especially sunflower and to close the gap between edible oil production and demand. Field experiments were conducted during the main seasons of 2022 and 2023 ​at the agricultural research station of National Research Centre, Nubaria, Egypt to investigate the effects of potassium nitrate (0, 20, 40, 60 ​kg K₂O fed⁻¹) (fed ​= ​feddan ​= ​2.4 ​ha) and zinc sulfate (0, 25, 50, 75 ​ppm Zn) on growth, oil yield, nutrients components and chemical composition of sunflower. Results indicated that application of potassium nitrate has a promoted effect on chlorophyll content, growth parameters (Head weight, head diameter and 100 seed weight), protein content, oil yield as well as nutrient content under all applied levels. The data also showed that the highest significant increase occurred with the soil application of 40 ​kg fed⁻¹ potassium nitrate combined with 75 ​ppm Zn foliar spray. Meanwhile, the lowest values were obtained at the control treatment. Therefore, the current study detected that potassium soil addition at 40 ​kg K₂O fed⁻¹, besides foliar application with 75 ​ppm Zn are important to improve the growth, macro-micronutrient, seeds and oil productivity of sunflower crops. Oil yield and nutrient content exhibit a strong positive correlation, with a correlation coefficient of 0.903 for N, 0.94 for P, 0.962 for K and 0.966 for Zn. This indicates that a higher nutrient percentage is associated with higher oil content of sunflower. Study underscores the importance of comprehending the interplay between potassium and zinc treatments in sunflower plants to enhance growth, yield, and oil production effectively. Understanding these relationships can lead to optimized cultivation practices and improved outcomes in sunflower farming.