Effects of Sowing Date on the Yield Performance and Quality Traits of Maize Hybrids Under Sustainable Agricultural Practices

Cereal cultivation is influenced by the interaction among genotype, climatic conditions, and cultivation technology—factors that determine yield level, yield stability, and grain quality. In the context of climatic variability, identifying efficient and sustainable cultivation strategies is a priority for modern agriculture. This study aimed to investigate the effects of sowing date, maize genotype, and growing-season environmental conditions on the stability and quality of maize yield in a soybean–wheat–maize crop rotation. A field experiment spanning five consecutive growing seasons (2021–2025) was conducted at the Agricultural Research and Development Station Turda, Romania, using 11 early and semi-early maize hybrids. Three sowing dates were established according to soil temperature: 6 °C (E I), 8 °C (E II), and 10 °C (E III). Analysis of variance indicated that year, sowing date and their interaction (Y × S) exerted highly significant effects on grain yield and all quality traits (p < 0.001), highlighting the substantial influence of interannual environmental variability. Yield generally increased with higher soil temperature at sowing, with E III showing favorable productivity and comparatively stable performance across environments. Sowing at 10 °C also generally favored protein and oil accumulation, whereas fiber content showed no consistent response among years. Overall, the results demonstrate that sowing time should be assessed together with seasonal climatic conditions to support stable maize yield and grain quality under variable environments.