Assessment of Wood Ash Application on Yield Advantage Indices of Maize and Lima Beans in an Intercrop

Alternate planting combinations of maize (Zea mays L.) with lima bean (Phaseolus lunatus L.) using wood ash as soil amendments were compared with the sole planting of each crop during the late 2014 and early 2015 planting seasons at the Teaching and Research Farm of the Federal University of Technology, Akure. The experiment in each season adopted three patterns of intercropping using ash as a soil amendment and laid out in a Randomized Complete Block Design (RCBD) with three replications. The experiment comprised 10 treatments: Sole planting of maize amended, sole planting of maize unamended, sole planting of lima beans amended and sole planting of lima beans unamended. Others were; 75:25 maize-lima beans amended, 75:25 maize-lima beans unamended, 50:50 maize-lima beans amended, 50:50 maize-lima beans unamended, 25:75 maize-lima beans amended and 25:75 maize-lima beans unamended. Wood ash was applied two weeks after planting at the rate of 2.4 kg (4 tons per hectare) to each plot. The combined yield advantage in terms of land equivalent ratio (LER) indices was greatest (1.95) in the case of 3 rows of maize and 1row of lima beans intercropping arrangements. Competition indices (CR) for all crops in all intercropping arrangements were more than 0.1 indicating that both crops were equally competitive. However, crop aggressivity (A) showed that maize was more dominant than lima beans due to plant population. Costs and returns analysis revealed that maize and lima beans intercropping at all proportions were more profitable than their corresponding monocrops.