EFFECT OF FERTILIZER COMPOSITION AND APPLICATION TIMING ON GRAIN YIELD AND QUALITY OF WINTER WHEAT

Under irrigated farming conditions, the effects of integrated application of mineral fertilizers (NPK), organic materials (well-decomposed manure - FYM), and biostimulants, as well as split nitrogen application across phenological stages (split-N), were evaluated for winter wheat in terms of grain yield and quality. In 2024, field trials were conducted in the Zafarabad and Dustlik districts of Jizzakh region. The achieved grain yield ranged from 6.2 to 7.5 t/ha; in production-scale experiments with the cultivar Grom, a maximum yield of 7.5 t/ha was recorded. Economic calculations indicated a net profit of 3.12–12.97 million UZS/ha. Split nitrogen application (3–4 splits) combined with late-season foliar feeding at the anthesis stage, consistent with findings from global meta-analyses, increased grain yield by an average of 3–8% and grain protein content by 4–9%. Organo-mineral integration (e.g., 10 t/ha FYM + ≈26 kg P/ha) and balanced potassium supply improved nitrogen use efficiency and the technological quality parameters of the grain. The obtained results demonstrate the potential to achieve actual yields above the national average for Uzbekistan (≈4.6–5.2 t/ha).