Cowpea Yield Response to Sowing Dates and Irrigation Intervals

Four soil profile pits were dug under differing cropping systems at Nigerian Institute For Oil Palm Research (NIFOR) experimental plantations in Benin City and chemically analysed. Cropping systems were sole oil palm, oil palm with cassava, oil palm with plantain, and oil palm with coconut. Samples were collected at 0 – 20, 20 – 40, 40 – 60, 60 – 80 and 80 – 100cm depth and analyzed for K, P, Ca, Mg, C and N. Sole oil palm gave the highest soil P, Ca, OC and pH within 100cm. The N and K were generally inadequate. Intercropping reduced nutrients up to 100cm depth. Nutrients reduced with soil depth