Agrochemical analysis of irrigated gray-brown (chestnut) soils in the Ganja-Dashkasan Economic Region, Azerbaijan, during 2022–2024 revealed low levels of plant-available nutrients, including ammonium and nitrate nitrogen, available phosphorus, and exchangeable potassium. As per national classification, these soils had poor supplies of essential nutrients and need application of mineral fertilizers to maintain soil fertility and ensure optimal growth and productivity of sunflower (Helianthus annuus L.). This study evaluated the effects of balanced nutrient supply on the growth and yield of sunflower under irrigated conditions. Field experiments conducted were in a randomized complete block design (RCBD) with three replications. Nitrogen, phosphorus, and potassium fertilizer applications were at recommended rates using split applications. The results showed mineral fertilization significantly increased leaf area. The largest leaf area was evident under the N120P120K120 treatment. Furthermore, balanced fertilization improved physiological activity, resulting in an enhanced plant growth and a higher yield performance.

Keywords: Sunflower (Helianthus annuus L.), mineral fertilization, nutrient management, irrigated soils, crop growth, yield performance

Key findings: In sunflower (H. annuus L.) growth traits (leaf area and physiological processes) and yield, the highest improvement was successful by using the fertilization treatment of N₁₂₀P₁₂₀K₁₂₀.