Time of introducing component crop influences productivity of intercropping system

Field experiment was conducted at National Horticultural Research Institute (NIHORT), Mbato Sub-station, Okigwe, Imo State, South-eastern Nigeria in the 2012 and 2013 cropping seasons to establish the most appropriate time to introduce component crops in cocoyam/cowpea mixture. Five different planting schemes (two and four weeks before, two and four weeks after and same day) and two cowpea genotypes (climbing Akidienu and erect IT97K-499-35) were used. The component crops were grown in monocultures to assess the productivity of the systems. The experimental design used was a completely randomized design with three replicates. Growth and yield of cocoyam and the cowpea genotypes increased significantly (P<0.05) when either of the component crops was planted earlier than the other. Intercropping reduced significantly (P<0.05) cocoyam yield by 0.7 − 74% in IT97K-499-35 and 22 − 80% in Akidienu. Sowing the cowpea genotypes the same day or before cocoyam resulted in over-yielding of cowpea, whereas sowing Akidienu and IT97K-499-35 after cocoyam caused pod yield reductions of 64% − 73% and 32% − 59% on average, respectively. Cocoyam planted two weeks before IT97K-499-35 produced more satisfactory yields of the intercrops than the other planting schedules with LER, LEC and ATER of 2.15, 1.03 and 1.57, respectively.