Research on Nitrogen Management in Winter Wheat Cultivated on Chernozem Soil for Yield Optimization

Nitrogen is one of the most essential nutrients for agricultural crops, and optimizing nitrogen fertilization enables the achievement of high yields and improved quality. In this context, the aim of the study was to identify the nitrogen form that significantly influences wheat yield, as well as the cultivars that respond positively to specific form of nitrogen fertilization, in order to provide recommendations regarding cultivar selection and the appropriate technological approach for chernozem soils in southern Romania. Over a period of three years (2021–2024), 36 winter wheat cultivars were tested under three distinct fertilization conditions: nitrate nitrogen, ammonium nitrogen, and nitrate + ammonium nitrogen, each applied in three different rates: 120 kg/ha a.s. (active substance), 150 kg/ha a.s., and 170 kg/ha a.s. The comparative performance of each cultivar relative to the others was evaluated using the Newman-Keuls multiple range test. The coefficient of variation (CV) of the obtained yields was used to determine yield stability, and its correlation with yield levels allowed for the identification and recommendation of cultivars that simultaneously demonstrated high yields (above average) and good or moderate stability. Among the tested cultivars, Sacramento was identified as the most productive, showing statistically significant superiority compared to both controls under all nitrogen fertilization treatments.