Performance of Sweet Potato and Soybeans as Affected by Cropping Sequence in the Northern Guinea Savanna of Nigeria

A field experiment was conducted to study the performance of sweet potato and soybeans under different cropping sequences during the raining seasons of 2007, 2008 and 2009 in Bauchi, Nigeria. The cropping sequences consisted of sweet potato transplanted 1 week after soybeans (+1), sweet potato transplanted 2 weeks after soybeans (+2), sweet potato + soybeans planted simultaneously (0), sweet potato transplanted 1 week before soybeans (-1), sweet potato transplanted 2 weeks before soybeans (-2), Sole sweet potato (Ssp) and Sole soybeans (Ssb). These were arranged in randomized complete block design with four replications. Percent production of tubers and pods as well as tuber and grain yields of component crops were significantly increased (p = 0.05) by the cropping treatments in all the three seasons of this study. However, same parameters do not statistically differ from one treatment to another in each season, except in percent tuber production with sole sweet potato in both 2008 and 2009 as well as in tuber yield with sole sweet potato in 2009. Therefore, component crops can be sole-grown or adopt sweet potato transplanted a week or 2 before soybeans-sequence for better tuber and grain yields.