Evaluation of some extra-early- and early-maturing cowpea varieties for intercropping with maize in southern Guinea Savanna of Nigeria
Agriculture and Biology Journal of North America
Two field experiments were undertaken between 2008 and 2009 at the Teaching and Research Farm of the University of Agriculture,Makurdi and at the National Root Crops Research Institute Sub-Station, Otobi (both located in Southern Guinea Savanna agro ecological zone of Nigeria) to evaluate fourteen improved extra-early-and early-maturing cowpea varieties in sole and in intercropping systems. The work aimed at assessing the productivity of these cowpea varieties and competitive interactions with
... he maize component as well as the profitability of cowpea/maize intercropping systems. The first experiment was laid out in randomized complete block design with three replications in each of the two locations. IT04K-221-1, IT03K-316-1,IT03K-324-9,IT03K-351-1,IT00K-1217, IT98K-692, IT99K-377-1, IT03K-378-4 cowpea varieties proved superior to the Ife Brown(check) in number of pods produced per plant, dry pod weight and grain yield, and therefore were selected for further investigation under intercropping .Grain yield advantage of IT04K-221-1 over Ife Brown was370.69%.The selected cowpea varieties, along with the Ife Brown(check), were intercropped with maize in split-plot experiment laid out in randomized complete block design with three replications at Otobi for two seasons.. Intercropping depressed the number of branches per plant and the dry grain yield of cowpea but did not influence the number of pods per plant, number of seeds per pod and the pod length of cowpea. Maize grain yield reductions resulting from intercropping varied from 49.26% to 72.41%, depending on the cowpea variety. Intercrop advantages measured by land equivalent ratio, area x time equivalency ratio; land equivalent coefficient indicated that IT04K-221-1, IT03K-316-1, IT03K-324-9, IT98K-692 and IT00K-2117 proved most productive under intercropping. Competitive indices (competitive ratio and aggressivity) showed that cowpea was the more competitive component of the intercropping. Sole cowpea had a mean net benefit of -N560.00/ha, while intercropped cowpea gave a mean value of N 11330.00/ha, implying that growing extraearly-and early-maturing cowpea in sole systems would result in losses. Intercropped IT04K-221-1 produced the largest net benefit (N 42425.00/ha), while IT03K-378-4 gave the lowest (-N 16300.00/ha).