Cutting Interval Effects on Dry Matter Yield and Nutritive Value of Alfalfa under Rainfed Condition in South Korea

Background: This study aimed to evaluate the effects of cutting interval on alfalfa (Medicago sativa L.) production and nutritive value in the central region of South Korea under rainfed conditions. Methods: Alfalfa was sown using a drill seeding method at a rate of 20 kg ha-1 on March 18, 2020. The experiment followed a randomized complete block design with three cutting interval treatments (28-, 36- and 48-day intervals). A regression model was developed to analyze both accumulated dry matter yield (DMY) and average crude protein (CP), as well as average relative feed value (RFV). Result: Accumulated DMY at 48- and 36-day intervals appeared higher than the 28-day interval (P less than 0.05). In terms of nutritive value, the 48-day interval resulted in significantly lower CP, compared to the other cutting intervals (P less than 0.05). RFV of 28- and 36-day intervals were significantly higher than the 48-day interval (P less than 0.05). The crossover of the linear regression model between accumulated DMY with average CP and average RFV indicated a cutting interval of 32-day, respectively. Taken together, the field study and regression results support a recommended cutting interval of around 36 days, which is about two weeks shorter than the conventional cutting interval under rainfed conditions in the central region of South Korea.