Abstract
Sustainable quality herbage production is related with defoliation management of the dwarf variety of late heading type (DL) of napiergrass (Pennisetum purpureum Schum.) in northern Kyushu, Japan. The optimal closing date in autumn for sustainable use and the optimal defoliation stage for maximizing quality herbage production with silage processing were ascertained for DL napiergrass transplanted in Shimabara, Nagasaki Prefecture in late May in 2004, 2005, and 2006. Closing dates were set at two levels in mid-late October and mid-late November for plants established in 2004 and 2005, showing higher winter survival for mid-late November closing-cut. Nutritive values and fermentation quality of round-bale silage were examined at three growth stages based on plant length in 2008 for plants established in 2004 : at or below 110cm, 120cm, and above 130cm. Results show that harvest at the 150cm of plant length is the optimal for making good quality silage processing, with maintaining high dry matter yield and good plant quality. Suitability for two sites on Kyushu’s main island and two sites on remote islands was examined for June or July transplanting in 2007, showing high winter survival at 95%.
