Growth Attributes and Pod Yield of Four Cowpea (Vigna unguiculata (L.) Walp.) Varieties as Influenced by Residual Effect of Different Application Rates of Farmyard Manure

Field trials were conducted in 2005 and 2006 rainfed conditions at the Institute for Agricultural Research farm, Samaru to test the pod yield response of four cowpea(Vigna unguiculata (L) Walp) varieties (IT93K-452-1, IT90K-82-2, IT97K-499-35 and IT96D-757) under four rates of residual farmyard manure, FYM (0, 5, 10 and 15 t FYM ha-1) using split plot design and three replication. Residual FYM significantly enhanced soil chemical composition. Taller plants with longer pods were observed in plots supplied with 10 t FYM ha-1. Plots supplied with lower rate of 5 t FYM ha-1 had plants with more leaves and branches and higher pod yield. Variety IT93K-452-1 and IT97K-499-35 were taller while IT93K-4542-1 flowered and matured earlier. Bigger pods were produced by IT90K-82-2 and IT96D-757. IT97K-499-35 had the highest pod yield. IT93K-452-1 exhibited the least growth. IT97K-499-55 grown in plot supplied with 5 t FYM ha-1 t produced the highest pod yield ha-1.