Evaluation of the agronomic characters of three sweet potato varieties for intercropping with soybean in Makurdi, Southern Guinea Savannah, Nigeria

J.A. Idoko, P.O. Osang, M.O. Ijoyah

Plant Science Archives 1(1), 31-43, 2016.


Field experiment was conducted under rain-fed conditions at the teaching and research farm of the University of Agriculture, Makurdi (7.140N and 310E) Nigeria during the 2011 and 2012 cropping seasons, to investigate the effect of intercropping three varieties of sweet potato and soybeans on the performance of sweet potato and soybeans. The experiment was a 2×3 split plot laid out in a randomized complete block designed in three replications. Main plot consisted of cropping systems. (sole sweet potato), sole soybeans and intercrops of sweet potato with soybeans. Sub plot consisted of varieties of sweet potato (CIP440037, CIP44014 and NRSP/05/007C). Growth, yield and yield components were determined for sweet potato and soybeans. There was significant (p<0.05) reduction in number of branches and vine lengths of sweet potato across varieties as a result of intercropping in both years of the experiment. Similar reductions were observed in number of roots per plant and marketable roots due to intercropping. Sweet potato variety NRSP/05/007C recorded the highest yield (15 tons/ha), number of roots/plant (4.67) and number of marketable roots when intercropped with soybeans. Intercropping significantly reduced the number of pods (30%) of soybean per plant and the grain yield (44%). All intercropping combinations of sweet potato varieties with soybeans had land equivalent ratio (LER) greater than unity (LER>1.00) indicating yield advantages. Highest percentage land saved (23.05 and 32.57) were obtained when soybeans was intercropped with sweet potato variety NRSP/05/007C in both seasons.