Yield Comparison between Conventional High Ridge Cultivation and Large Ridge Cultivation in Relation to Conventional Vine Planting and Tuber Seedling Transplanting of the Sweet Potato Cultivar ‘Murasakimasari’

Abstract

Two field experiments were conducted using the sweet potato cultivar ‘Murasakimasari’ with both conventional vine planting (CVP) and tuber seedling transplanting (TST) to estimate yield properties under large ridge (LAR) cultivation with two rows in a ridge and compared with the conventional high ridge (CHR) cultivation method. The LAR shapes were LAR1 (ridge height [RH], 35 cm; ridge distance [RID], 180 cm; ridge bed width [RBW], 120 cm; ridge shoulder width [RSW], 90 cm; and furrow, 60 cm) and LAR2 (RH, 35 cm; RID, 160 cm; RBW, 100 cm; RSW, 70 cm; and furrow, 60 cm) in 2008, and LAR3 (RH, 35 cm; RID, 160 cm; RBW, 110 cm; RSW, 80 cm; and furrow, 50 cm) in 2009. In 2008, the LAR1 and LAR2 cultivations were not superior in root tuber yield to the CHR cultivation. In 2009, we investigated the yield properties by including the planting density factor (2.222, 1.852, and 1.500 hills m^-2) within the ridge cultivation modes (CHR/LAR3) and planting modes (CVP/TST). The lowest root tuber yield was obtained in the LAR3×CVP×1.852 treatment (3784 g m^-2). With respect to the two-factor interaction between ridge modes (CHR/LAR3) and planting modes (CVP/TST), the lowest yield was obtained in the LAR3×CVP treatment (4079 g m^-2), and under LAR3 conditions, the yield was higher under TST (5169 g m^-2) than under CVP at the 1% level. These results suggested that the TST method might be suitable, while the CVP method would be unsuitable, for the LAR3 cultivation. The results obtained in this study could be useful for future studies on ridge shape for sweet potato cultivation.