Nitrogen Fertilization and Its Effect on Silage Maize Quality in the Context of Sustainable Fertilization Practices

Sustainable agriculture, particularly efficient nitrogen management, is essential for maintaining soil fertility, improving crop quality, and reducing the environmental footprint of agricultural production. This study evaluated the effects of reduced soil-applied nitrogen and foliar application of the nitrogen–sulfur fertilizer Nitron-S on the quality of silage maize (Zea mays L.). A field experiment was conducted using a single-factor design with four fertilization treatments differing in nitrogen supply and foliar fertilization intensity. The silage maize cultivar Farmmortiz was grown under uniform manure application (30 t ha−1) applied in autumn. The control treatment received the full soil-applied nitrogen rate, whereas experimental treatments received 50% of the conventional nitrogen dose supplemented with foliar Nitron-S at doses of 20, 40, and 60 dm3 ha-1, applied twice during the growing season. After harvest, plant yield and selected quality parameters were determined, including dry matter, crude protein, sugars, starch, ash, neutral detergent fiber (NDF), acid detergent lignin (ADL), ammonia fraction, and organic matter digestibility (VOS). Fertilization treatments significantly affected most quality traits. The highest Nitron-S rate increased starch concentration (up to approximately 30% under N4) but also elevated ADL content (by about 25%) and slightly reduced VOS (only by about 1–3%. Partial replacement of soil-applied nitrogen with foliar nitrogen–sulfur fertilization improved the nutritional quality of maize silage and reduced nitrogen input. This approach may contribute to more sustainable maize production.