Effect of Seeding Date and Varieties of Italian Ryegrass on Forage Yield and Quality of Early Spring-seeded at Paddy Field in Southern Region

Italian ryegrass is generally cultivated by a winter forage in a paddy field, the harvest season overlaps with rice transplantion in some cases. In addition, farmers can miss the optimal seedtime for Italian ryegrass because of the rainy season. Therefore, this research was conducted between October 2012 and June 2013 in Kwangjin, Korea to examine the effect of spring-seeding on the yields and quality of Italian ryegrass for the determination of an alternative if the optimal seedtime is missed. This trial consists of four different seeding dates (15 February, 25 February, 5 March, and 15 March) and three varieties (Kowinmaster, Kowinearly, and Green farm). The Italian ryegrass varieties Kowinmaster, Kowinearly, and Green farm were sown on February 15. The heading date of each variety showed from May 12 to May 9 and interval time of five days but the Treatment of March 15 planting date showed three days interval. The Kowinmaster variety, planted on February 15, was 93.0 cm taller on March 15 with a height of 105.7 cm. The Kowinearly and Green farm varieties planted on February 15 were of a similar height on February 25 and received a poor lodging score when planted quickly. The dry matter (DM) yield of the Kowinearly planted on February 15 was high but that of Green farm was low at 6,609 kg/ha and a difference was not shown between the varieties. The DM yield was different for those varieties planted on February 15 and March 15 (P0.05). The crude protein content (CPC) of those varieties planted on February 15 showed an average of 8.8%, while those that were planted on March 15 showed an average that was about 2.3% higher at 11.1%; furthermore, the latter also showed lower acid detergent fiber (ADF) and total digestible nutrient (TDN) contents, by 2.1% and 1.5%, respectively. The relative feed value was about 5.9% higher, depending on the seeding date, as well as being slower and showing less difference between the varieties. According to this study, Italian ryegrass planted in a paddy field of the southern region of Korea on February 25 will produce a high-quantity yield with nutritive value.