The objective of this study was to assess the effects of gypsum application on dry matter yield (DMY), mineral content of alfalfa (Medicago sativa L.), and soil properties in reclaimed tidal land in South Korea. The experiment was conducted in Seokmun, located on the west coast of South Korea, which is reclaimed with approximately 70 cm depth of degraded island soil. Treatments consisted of a control with no gypsum application (G0), 2 ton ha-1 (G2), and 4 ton ha-1 (G4) of gypsum application. The first harvest was carried out when the alfalfa reached 10% flowering, and subsequent harvests were conducted at 35-day intervals. Over the three-year experimental periods (2019-2021), the total DMY of G2 treatment was significantly higher than those of G0 and G4 (p<0.05). Although both G2 and G4 gypsum application treatments lowered soil pH, the G4 treatment increased the electrical conductivity (EC) content of the soil. Additionally, gypsum application affected the mineral contents of alfalfa, resulting in reduced concentration of sodium (Na) and Magnesium (Mg). Therefore, this present study suggests that a gypsum application rate of 2 ton ha-1 is optimal for improving alfalfa dry matter yield and mineral balance, as well as enhancing soil chemical properties in reclaimed tidal land in South Korea.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
Ⅲ. RESULTS AND DISCUSSION
    1. Weather condition
    2. Dry matter yield
    3. Soil properties
    4. Mineral contents in alfalfa
Ⅳ. CONCLUSIONS
Ⅴ. ACKNOWLEDGEMENTS
Ⅵ. REFERENCES

• Doohong Min(Department of Agronomy, Kansas State University, Manhattan, Kansas 66506, USA)
• Sourajit Dey(Department of Agronomy, Kansas State University, Manhattan, Kansas 66506, USA)
• Kyung Il Sung(Department of Animal Life Science, Kangwon National University, Chuncheon 24341, South Korea)
• Byong Wan Kim(Department of Animal Life Science, Kangwon National University, Chuncheon 24341, South Korea) Corresponding author
• Jinglun Peng(College of Pastoral Agriculture Science and Technology, State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou 730020/730000, China)
• Myung Kyo Kim(School of Business, Hanyang University, Seoul 04763, South Korea)
• Rudra Baral(University of Missouri Extension, Columbia, Missouri 65211, USA)
• Ji Yung Kim(Department of Agronomy, Kansas State University, Manhattan, Kansas 66506, USA)