The optimal determination of seeding rate is critical to minimizing uncertainties about the large variations observed in forage quality and productivity when alfalfa is cultivated under different geographical areas and growing conditions. The objective of this investigation was to provide information about the proper seeding rate according to harvest timing for alfalfa cultivation in the Northern regions of Korea. Alfalfa was sown in September 2018 at a seeding rate of 20, 30 or 40 kg/ha and harvested four times in 2019: May 3, July 2, September 11, and October 13. Regardless of seeding rate, alfalfa plant height was longest at the third harvest (113 cm) and the shortest in the last annual harvest (43.8 cm). However, seeding rate had no effect on alfalfa plant height at any harvest. Forage relative feed value was increased in the first cutting but decreased in the third cuttings as seeding rate increased. However, seeding rate had slight effect on alfalfa forage quality components at the second and fourth cuttings. Total annual DM and crude protein production (in 4 harvests) was greater at higher seeding rates. Plots seeded at a rate of 40 kg/ha produced on average 1,257 and 2,620 kg/ha more forage (DM basis) than those seeded at a rate of 30 or 20 kg/ha, respectively. Forage DM production at the first, second, third, and fourth harvests accounted for 36.1, 24.0, 27.1, and 12.8 % of total annual DM production, respectively. Overall, small differences were seen when alfalfa seeding rate was different but maximum forage DM production (in four harvests) was detected when seeding rate was 40 kg/ha. These data could be useful to the alfalfa growers by allowing them to make more accurate trade-offs between seed price and the expected magnitude of forage yield gains in order to select the best seeding rate.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Experimental location and alfalfa management
    2. Measurements
Ⅲ. DATA ANALYSIS
Ⅳ. RESULTS
    1. Forage component quality
    2. Alfalfa forage productivity
Ⅴ. DISCUSSION
    1. Forage productivity
    2. Forage quality components
Ⅵ. CONCLUSIONS
Ⅷ. REFERENCES

• Kim Jong Geun(Graduate School of International Agriculture and Technology, Seoul National University/Research Institute of Eco-Friendly Livestock Science, Institute of Green Bio Science and Technology, Seoul National University) Corresponding author
• Jeong Eun Chan(Graduate School of International Agriculture and Technology, Seoul National University)
• Li Yan Fen(Graduate School of International Agriculture and Technology, Seoul National University)
• Kim Hak Jin(Research Institute of Eco-Friendly Livestock Science, Institute of Green Bio Science and Technology, Seoul National University)
• Ahmadi Farhad(Research Institute of Eco-Friendly Livestock Science, Institute of Green Bio Science and Technology, Seoul National University)