This study evaluated the impact of sowing dates on the growth, yield, and nutritive quality of three corn cultivars including Gwangpyeongok, Dacheongok, and Shinhwangok. Plant height and total yield components declined with delayed sowing across all cultivars. Gwangpyeongok achieved the highest plant height (289 ± 14 cm), grain yield (9,108 ± 82 kg/ha), and total yield (18,973 ± 2,560 kg/ha) at the April 29 sowing. Dacheongok recorded the highest stover yield (17,227 ± 137 kg/ha) and total yield (22,236 ± 1,053 kg/ha) on May 13. Shinhwangok reached its maximum total yield (19,158 ± 604 kg/ha) at May 13 but showed the sharpest declines by May 16. Nutritional quality also deteriorated with later sowing. In stover, crude protein (CP) declined to 3.58% in Shinhwangok at May 16, accompanied by a rise in neutral detergent fiber (NDF) to 69.9%. In contrast, Dacheongok maintained stable CP levels (5.27–5.60%) and the lowest fiber fractions. Gwangpyeongok exhibited the highest stover CP at April 29 sowing, along with the lowest NDF and acid detergent fiber (ADF) contents. Grain CP was highest in Gwangpyeongok (8.1 ± 0.4%) and Shinhwangok (9.6 ± 0.9%) at April 29, while Dacheongok showed its maximum grain CP (8.0 ± 0.3%) at the same sowing date, coupled with relatively low fiber content. Overall, the findings highlight that timely sowing is crucial for achieving both high yield and optimal nutritive quality in maize. For Gwangpyeongok and Dacheongok, sowing from late April to mid-May provided the best balance between yield and nutritional quality. In Shinhwangok, the highest stover, grain, and total biomass yields were obtained at the May 13 sowing.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Experimental field
    2. Corn cultivations
    3. Data analysis
    4. Statistical analysis
Ⅲ. RESULTS
    1. Growth and yield of different corn cultivars at differentsowing periods.
    2. Nutrient content in stover of corn cultivars at differentsown dates
    3. Nutrient content in Grains of corn cultivars at differentsown dates
Ⅳ. DISCUSSION
Ⅴ. CONCLUSIONS
Ⅵ. ACKNOWLEDGEMENTS
Ⅶ. REFERENCES

• Ki Choon Choi(Forage Production System Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea) Corresponding author
• Jeong Sung Jung(Forage Production System Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• Seung Hak Yang(Forage Production System Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• Ilavenil Soundharrajan(Forage Production System Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Republic of Korea)
• Jae Hyuk Kim(Department of Agriculture, Korea National Open University, Seoul 03087, Republic of Korea)
• Ouk Kyu Han(Department of Crops and Forestry, Korean National University of Agriculture and Fisheries, Jeonju 54874, Republic of Korea)
• Hyo-Shim Han(Department of Biotechnology, Sunchon University, Suncheon 57922, Republic of Korea)