Abstract

Ipomea batatas (sweet potato) yield vary widely among farmers due to improper ridging and planting orientation. This study was to establish the proper ridging and planting orientation, so as to enhance constant reliable yields among sweet potato producing farmers. The objectives of the study were to compare vine length and to determine root yield, central root diameter and root length among different ridge heights and planting orientations. A 3 x 3 factorial in a completely randomised block design with 3 replications was used. Ridge height had levels; 30, 40 and 50 cm while planting angle had levels; horizontal 180°, inclined 45° and vertical 90°. Vine length was measured at 3, 6, 9 and 12 weeks after planting and root yield, root diameter and root length were measured at harvesting. Data was analysed using M STAT C for variance between treatment means. The results showed interaction effect (p = 0.05) of ridge height and planting angle on the vine length, root diameter, length and yield. Lower ridges produced longer vines than higher ridges. Decreasing inclination of cuttings also increases vine length. Root diameter decreases with increasing ridge height while root length increased as ridge height increased. Medium ridge height (40 cm) with inclined planting angle may be recommended for higher root yields and horizontal planting angle on low ridges can be used to produce rounded swollen roots.

Key words: Ridge, height, planting orientation, sweet potato, vine, yield.