Effect of Varying Nitrogen and Micronutrient Fertilization on Yield Quantity and Quality of Sunflower (Helianthus annuus L.) Achenes

Abstract

Sunflower is a good alternative crop in rotation, even in light soils. This is due to the changing climate, economic factors and the need to reduce agriculture pressure on the environment. In this field experiment, the effect of soil nitrogen doses (60 and 90 kg ha−1) and additional foliar fertilization (B, Cu, Fe, Mn, Mo, Zn) on selected plant characteristics, yield and quality of sunflower achenes was assessed. The single-factor experiment was conducted in 2020 and 2021 on Luvisol soil. It was shown that a higher nitrogen dose had a positive effect on plant biometric features, protein content in achenes, as well as LAI (leaf area index) and SPAD (soil plant analysis development) indices. Additionally, the applied double foliar spraying resulted in an increase in yield components and quality of achenes. Sunflower yielding depended on the interaction of weather conditions with fertilization. In the first year of the research, high yields were obtained after applying 60 or 90 kg N ha−1 in combination with double foliar fertilization (3.68 and 3.65 t ha−1, respectively). A significantly lower yield was recorded after applying only the 60 kg N ha−1 dose. This was not statistically confirmed in the second year of the study, with a higher average yield of 3.79 t ha−1. Economic calculations showed that the optimal option was to use 60 kg N ha−1 together with single or double foliar fertilization. Fertilizing with 90 kg N ha−1 in combination with micronutrient spraying was the least profitable.