Responses of sunflower biomass subjected to different water replacements and NPK sources

Sunflower is an important agricultural crop with high water demand for optimal development. This study aimed to evaluate the physiological responses of sunflower plants subjected to different irrigation levels and NPK fertilizer sources under protected conditions. The experiment was conducted in pots placed in a greenhouse, with controlled water deficit via lysimeters and application of various doses of NPK fertilizers, in both mineral and organomineral forms. The variables analyzed were fresh mass, dry mass, and water content of the floral capitulum. Results showed that irrigation levels between 103% and 125% led to greater accumulation of dry matter in the leaves and stems. In contrast, increasing NPK doses reduced leaf and stem dry mass, possibly due to toxic effects at doses exceeding crop recommendations. Organomineral fertilization demonstrated a positive effect on the development of leaf and stem biomass. Further studies are recommended to explore the use of alternative natural fertilization strategies in sunflower cultivation.