Effects of Soil and Foliar Application of Zinc Sulfate On Yield and Quality Parameters in Hazelnut

Zinc (Zn) fertilization plays a crucial role in hazelnut production by increasing yield and fruit quality. Zinc is an important micronutrient for hazelnut plants and that Zn content contributes to increased fruit set and improving hazelnut quality. In this study, the effects of the application of soil Zn, foliar Zn, and combined soil Zn and foliar sprays on the improvement of productivity and quality parameters of hazelnut kernels were investigated. The results showed that the application of S1 (1.1 kg Zn ha⁻¹, soil) increased yield and quality compared to the control. A similar increase was also obtained with foliar application of Zn. With the application of S1+F1 (1.1 kg Zn ha⁻¹ soil +0.3% Zn foliar sprays), the highest yield and quality parameters such as nut weight, kernel weight, kernel percentage, nut size and kernel size increased, and the number of blank nuts and defective kernels decreased. In contrast, efficiency increased in applications S2 (2.2 kg Zn ha⁻¹ soil) and S2+F1, but quality, such as nut weight and kernel size, deteriorated. The amount of Zn in the soil application and the timing of foliar application contribute to the improvement of quantitative and qualitative traits that are crucial for future sustainable hazelnut production.