Response of Winter Wheat to Delayed Sowing and Varied Nitrogen Fertilization

Common wheat is one of the most important cereal crops in the world. In cultivation, winter, spring, and facultative varieties of this species are known. In wheat agronomy, timely sowing and optimal nitrogen fertilization are particularly crucial practices, as both significantly impact yield and grain quality. In a three-year field experiment, the response of the winter wheat variety RGT Kilimanjaro to two sowing dates (recommended and delayed by 30 days) and varied nitrogen fertilization levels (100 kg ha⁻¹, 150 kg ha⁻¹, and 200 kg ha⁻¹) was investigated. It was shown that the difference in grain yield between 2021 and 2023 amounted to 0.74 kg ha⁻¹. The application of 200 N kg ha⁻¹ significantly increased the Soil Plant Analysis Development (SPAD) index and Leaf Area Index (LAI) compared to the variant with a delayed sowing date and a nitrogen dose of 100 kg ha⁻¹. Yield components (number of spikes per square meter, thousand grain weight) and grain yield were highest when wheat was sown at the recommended date and with the application of either 150 or 200 N kg ha⁻¹. The number of grains per spike significantly varied between the variant with the recommended sowing date and a dose of 200 N kg ha⁻¹ and the variant with a delayed sowing date and a dose of 100 N kg ha⁻¹. The lowest grain yield was obtained at a 30-day late wheat sowing date when applying 100 N kg ha⁻¹. The protein content in the grain was primarily influenced by nitrogen fertilization. Therefore, it can be concluded that delaying the sowing date of winter wheat by 30 days results in a decrease in grain yield but can be compensated by increased nitrogen fertilization. The most favorable economic effects were achieved with the application of 150 N kg ha⁻¹ at the recommended sowing date. Considering that high doses of nitrogen fertilization can have adverse effects on the natural environment, research in this area should be continued.