Assessment of intercropped sweet corn (Zea mays var. saccharata) and vegetable cowpea (Vigna unguiculata (L.) Walp) using competitive indices in the derived savannah of south-eastern Nigeria

摘要

Field experiments were established in 2009 and 2010 cropping seasons at Federal College of Agriculture project farm, Ishiagu, Ebonyi State, Nigeria to assess the biological and economic productivity of intercropping sweet corn with varying plant populations of vegetable cowpea using additive series technique in the derived savannah of south-eastern Nigeria. The experiment was laid out in a randomized complete block design (RCBD) with three replications. The plot size was 3 m x 3 m (9 m2). On the average over both cropping seasons, sweet corn intercropped with vegetable cowpea, especially at the highest cowpea population gave higher yield advantage in terms of total land equivalent ratio, (1.41), crop yield equivalent for sweet corn (4.71 t ha-1) and vegetable cowpea (2.03 t ha-1), total gross monetary returns (6,763.88 US dollars), monetary equivalent ratio (1.13), and monetary advantage index (2,308.81 US dollars). Therefore, for maximum financial returns, intercropping sweet corn with high vegetable cowpea populations is important because of enhanced productivity of the system, bonus yield and improved protein intake of the farmers from the cowpea component. Keywords: Sweet corn, vegetable cowpea, yield, biological and economic productivity.