Effect of Cutting Height on Dry Matter Yield and Nutritive Values of Giant Stargrass Over-seeded with Italian Ryegrass Sward in Cool-season Subtropical Okinawa, Japan

Abstract

Italian ryegrass (Lolium multiflorum Lam., IR) was over-seeded to giant stargrass (Cynodon plectostachyus (K. Schum.) Pilger, GS) sward for obtaining complementary herbage production in cool-season of subtropical Okinawa, Japan. We evaluated effects of two levels of cutting height (5 and 15 cm) on the dry matter yield and nutritive values of the over-seeded GS sward. The significant effect of cutting height on dry matter yield was only observed in GS pure sward, resulting in the lower yield for the 5-cm cutting height. Pure and over-seeded IR swards provided higher yield than the GS pure sward. Although the crude protein content was not significantly different among the pure and over-seeded swards, in vitro dry matter digestibility was about 20% higher in the pure and over-seeded IR swards than the pure GS swards. In the over-seeded swards, crude protein yield and digestible dry matter yield were highest among the observed swards in 15-cm and 5-cm cutting height, respectively. The results suggested that 5-cm cut GS sward over-seeded with IR might be one of the effective management practices for obtaining the high yield with quality herbage in cool-season of subtropical Okinawa.