Effects of Seeding Rate on Dry Matter Yield and Weeds of Guineagrass (Panicum maximum Jacq.) New Extremely Late Cultivar ‘Umaku’ as a Summer Annual Grass

Abstract

The Guineagrass new extremely late cultivar ‘Umaku’ is expected to replace existing tropical grasses in frosty areas because it does not reach the heading stage when cultivated as an annual grass in frosty areas and because it can be used as high-quality forage. This study was conducted to clarify the appropriate seeding rate of poor initial growth ‘Umaku’ as an annual summer grass from the perspectives of dry matter yield (DMY) and weed control. The DMY and weed mass of ‘Umaku’ were compared with those of rhodesgrass ‘Katambora’ as control at seeding rates of 0.5 to 4 kg/10 a using broadcasting. Results show that ‘Umaku’ had no heading or lodging at first cut in either of the investigated two years. Moreover, DMY showed similar or greater values than those of ‘Katambora’. The weed mass of ‘Umaku’ at first cut at both years was significantly less than that of ‘Katambora’ (P<0.05). The weed control effect of ‘Umaku’ was superior to that of ‘Katambora’. Furthermore, because the weed ratio was 5% or less at the seeding rate of 2 kg/10 a or more, a seeding rate of around 2 kg/10 a is recommended to allow for adequate weed control.