Effect of Seedbed Types and time of Vine Harvesting on Shoot and Tuber Yields of Sweet Potato [Ipomoea batatas (L.) Lam.] in South-south, Nigeria

A field experiment was conducted at Rivers Institute of Agricultural Research and Training (RIART), Rivers State University, Port Harcourt, Nigeria with the objective of evaluating the influence of seedbed types and vine harvesting time on shoot and tuber yields of sweet potato and make recommendations for optimal and sustainable production. The treatments consisted of three seedbed types (ridge, flat, and mound), and four vine harvesting time (8, 12, 16 and 20 weeks after planting). The experiment was laid out as a 3 x 4 in factorial arrangement fitted into a randomized complete block design (RCBD) and replicated three times. The results revealed that planting of sweet potato on ridge produced the highest root tuber yield followed by mound seedbeds; planting on flat seedbed produced the highest shoot (vine) and lowest tuber yields. While planting on ridge seedbed and harvesting the vines 16 weeks after planting (when about 80% of the growth phase of the plant was completed) produced optimum shoot yield which could be used as fodder with no significant effect on root tuber yield. In general, vine harvesting during active growth phase of the sweet potato plant seriously depressed tuber yield more than it affected shoot production. These results therefore stand as our recommendations for sweet potato production in the South-south zone of Nigeria.